4l80e Hard Shifting Problems

4L80e Transmission Rebuild. 4L80E SHIFT CORRECTION PACKAGE (Superior K400-WP ) Shift Correction Package. 4L80E Whines Louder After Hard Runs (1 2) cdub81. if you see no fluid try to drive it with the plug unplugged in reverse. also shifts hard from park into reverse. gm 4L80E trans My truck is an 1989 3500 it is the round hood like the 1990 to 2000 it is a littler hard to find a manual clutch for these. I'd not on my Suburban's 4L80E. i did a couple full manual 4l80e trans for a baja truck a few years ago. I have adjusted all the tables I understand with no luck. Fluid level okay while running, warm, level surface. I have seen several problems with the 4L60e transmission series. We thought this was a high miles problem, but find that it can happen in really hard hot service at any milage. If the Ford style is used, the 2 inputs not used for shift lever position determination can be used for datalogging voltage signals (temperatures, TPS, MAP, etc. 10 GPIO board from Bowling and Grippo when using it with the MegaShift™ transmission controller software for the GM 4L80E transmission (other transmissions may be similar but may require some changes to suit their requirements). If you can't just replace a single solenoid, and you have to replace the whole pack, it could be worth trying to change your transmission fluid first instead. Halfway to destination started shifting hard up and down in all gears. it shifts fine after that until you slow down enough to drop back into first. if you are under hard throttle, the shift is a bit smoother. Mine was $1500 to get rebuilt. I'm picking the car up up this. Names like EZ TCU and Simple Shift made us wonder if these controllers could live up to their hype. I have a 01 2500 HD with a 408 and a T-trim at 12 psi. These vehicles use either a T-700R4(4L60) or an 4L60E automatic overdrive transmission. It shifts very hard through all the gears and especially hard on the 1-2 shift. Buy Shift Rite Transmissions replacement for 4L60E 93-94 M30 Sonnax Update Control Valvebody Shift Rite 4L60E: Hard Parts - Amazon. Gm 4L80e transmission not shifting Hello, I'm a mechanic in the marine corp. Yes you can mate the 4L80E to the NP205 as I did with my 1980 Chevy 4x4 with a 1996 5. Harsh Shifts, P0730. Despite the advantages the 4L80E had over its predecessors, it still came with its problems such as losing the reverse gear and experiencing hard shifts. I pulled the trans and sent it to the transmission builder. 46390B 4L80E Transmission solenoid kit 04-up 4L80E transmission solenoid kit. I've read that some of the numbers in the tables have to be changed or "zero'd" when running a shift kitso I'll have to look in to that morebut right now I need to find someone that can do a tune, or someone that knows whats going on more that what I do(which isn't much) to fix my problemsfirst gear shifts way too early, overdrive shifts late. first out changing the filter will not make reverse come back. An ignition switch that goes bad can cause a false shift solenoid code that comes up on a scanner. You can also find other images like wiring diagram, parts diagram, replacement parts, electrical diagram, repair manuals, engine diagram, engine scheme, wiring harness, fuse box, vacuum diagram, timing belt, timing chain, brakes. You may have to register before you can post: click the register link above to proceed. Simple push button control allows for manual shifting with multiple integrated mechanical and RPM based safety lock outs to inhibit accidental shifting into Reverse or Park. I'd not on my Suburban's 4L80E. and i will say this about additives DO NOT USE THEM once you put the chemical into the transmission it does not stop working until you drain both the torque and the trans. Twitter Facebook YouTube Instagram. Hi all, I recently swapped out the harness and solenoids (solenoid kit) on my 4L80E. Standard gear ratio is the OEM 2. 4L80e Transmission Rebuild. 4L80E Performance Specs The 4L80E is a manual transmission that has a maximum engine input torque of 440 lb-ft and is capable of providing an output torque of up to 885 lb-ft. two problems with the 4l80e one could be line pressure, the other the 80e has a fail safe that wont let the trans shift to reverse if it senses a speed of greater than 8mph. 0L and 230,000 kms or 144k miles. The original owner replaced the trans at 100k and I took ownership at 190k. I'm having shifting problems during hard acceleration from a start and when tring to accelerate when already at a speed when the transmission downshifts. The Performance Automatic 4L80E is a proven street/strip (read: overdrive) automatic designed for big-blocks and high-power small-blocks, and the beloved LS. - GMC 1993 Sierra C3500 question. Login with Facebook. Need help 1993 4L80E won't shift to 4th. Now when at light to mid throttle, the shifting between all the gears is nice and easy almost not even noticeablebut at full throttle, the 1-2 shift delays a bit then kicks like a mule (I mean if you were holding a drink in your hand even with a lid it'd probably spill), 2-3 shift. This will cause intermittent shift problems as well as erratic engine codes. In the 4T60-E there is a PWM solenoid that controls how hard the shifts are, it does this by sort of "cushioning" the speed at which the fluid applies the bands. I picked it up for pretty cheap and it has had this problem since I bought it about 2k miles ago. Reduces Direct Clutch Burn - Up. Bt good newsI think I solved 90% of my problem. dropped the tranny pan and saw a lot of metal shavings. If a trouble code has returned repair as needed and recheck system. Despite the advantages the 4L80E had over its predecessors, it still came with its problems such as losing the reverse gear and experiencing hard shifts. All the shifting is. if your taking it easy, it slams into gear. The computer senses the lack of pressure created by that and increases it to compensate, which is what causes the hard shift. A transmission can prompt a whining noise if the operating system has malfunctioned, the gears are not operating correctly or the transmission fluid needs to be changed. or stuck off) and also P1870 ( Trans. im sure this is a 4L80E transmission and it has a problem with the. Pictured below are just a few of the Updates & Upgrades that go into each 4L80E Transmission. almost to soft. An ignition switch that goes bad can cause a false shift solenoid code that comes up on a scanner. my fluid is clean, no burn smell i drove home from the desert and the tranny was shifting perfectly fine ( this was on a saturday). Harsh Shifts, P0730. When you put the truck in second, it will start out in 2nd like it is suppost to. We also have pan gaskets and filters in the category along with High performance Transmission Fluid. By 1700 rpm problem disappears. In the 4T60-E there is a PWM solenoid that controls how hard the shifts are, it does this by sort of "cushioning" the speed at which the fluid applies the bands. When your transmission slams into gear it can be a sign of abnormal pressures, worn components or even a low fluid level. 4l80e problem symptoms and since my trans warn lamp doesn't work I have to do some good hard thinking. Pictured below are just a few of the Updates & Upgrades that go into each 4L80E Transmission. The answer is the PCM is in complete control of every aspect of when and how the 4L60E shifts, Line Pressure and Lockup. 4l80e shifting problems sometimes have to rev 3000 rpm to get from 1st to 2nd. Less is better to a point. My transmission finally gave up and I had to replace my transmission. All the shifting is. No CE codes when I scanned it. Almost scary hard, depending on what rpm you hit it at. How a Transmission Valve Body Works. Re: 2000 Year, Chevrolet, C3500 4L80E Transmission? I have built many TH350's and 4L60-E's in my times. i rebuilt mine myself, with a Compushift controller, 10" FTI converter, and Transgo HD 2 shift kit-other than changing all the bushings, sprags, good clutches, larger front stater bushing and rear anti walk washer, just a basic rebuild and stock hard parts-it was a 2004 unit, so had most of the factory upgrades-im making 569 RWHP, beat on it pretty good so far, guess i'll find the weak parts. Duncan writes: Hi Sajeev, I have a question about a 4L60-E transmission in a 2001 Chevy Suburban K1500. I've replaced TPS sensor and still having same exact problems. The problem started approximately a months after purchasing the vehicle. Less is better to a point. The truck eases around great. Problem may be intermittent: Check TPS for smooth electrical response. a good shift kit and valve body modification will increase line pressure. See our lemon odds and nada odds page to see vehicles with no repairs or vehicles with more than three repairs. Full Manual, Performance 4L80E Transmission, Level 4. Buy Shift Rite Transmissions replacement for 4L60E 93-94 M30 Sonnax Update Control Valvebody Shift Rite 4L60E: Hard Parts - Amazon. Platinum Series Street Smart 4L80E Transmission Kit ; Small Block Chevy,Big Block Chevy and LS: Torque Converter ; Smart Shift Controller ; Dipstick ; Dust Cover ; Mount & Hardware. Have Peace Of Mind, knowing that your new 4L80E Transmission has all the Updates developed by General Motors Engineers combined with the Latest Industry Advancements providing Unparalleled OE Strength and Durability. 81" torque converter) of transmission fluid, Top 30 Common 4L60E Transmission Problems and Repair Below is a list of common transmission problems with the GM 4L60E Transmission and possible solutions to repair. Does anyone know what the problem could be?. Like Glock said, if it also shifts really hard into second, the trans will need rebuilt of replaced. Check the yellow spring inside the accum housing for breakage. 4L80E Performance Specs The 4L80E is a manual transmission that has a maximum engine input torque of 440 lb-ft and is capable of providing an output torque of up to 885 lb-ft. If it sits for a couple hours it will shift normally. The 4L80E I have started acting like the converter was going bad the other day. Jesse Brown, friend on Facebook, then explained to me that there is no such thing as 0% load when using MAP for load indication. trans has started shifting very hard, especially from low to second. I've replaced TPS sensor and still having same exact problems. was it on a street vehicle or offroad vehicle? did you notice any differance in temp? did you leave the speed sensors in or are the plugs nessesary? was there any slippage or hard shifts while shifting under a load, or did you need to let off the throttle a bit? did you find the kit came with most everything needed to convert it to full. Truck has the 6. Late shifts, downshift clunk, 3-4 clutch failure, no lockup, 2-4 band failure, early shifts, 1-2 slide/bump, 2-3 cut loose; reverse clutch failure, 83-87 lets you make T. it shifts fine after that until you slow down enough to drop back into first. The RPMs will jump up but the ****** will not shift. A transmission can prompt a whining noise if the operating system has malfunctioned, the gears are not operating correctly or the transmission fluid needs to be changed. Shifting problems with NP243 Transfer case with the 411 PCM Hi all, Some of you will recall that my Ms Beastly project (8. Flex plate: You will need a flexplate and spacer from ¾ ton GM truck that originally came with a 4L80E. The owner continued driving the vehicle, and has hard shifting. 1998 and up, if vehicle has torque management this kit will not make hard shifts. I have no passing gear, No overdrive and hard shifting from 1st to 2nd. The Transmission Rebuilders Network is the place where the industries best transmission rebuilders work together to help solve the most complex automatic transmission problems. These vehicles use either a T-700R4(4L60) or an 4L60E automatic overdrive transmission. have driven it many miles with this problem but it will still drive anywhere and back. idk how it would compared to my 2011 in hard driving. When the car feels like its taking off from a dead stop in 2nd stop the car. Any Transmission Guru's on the 4L80E. An ignition switch that goes bad can cause a false shift solenoid code that comes up on a scanner. Looking for E Sierra? We feature an extremely large selection of E Sierra and comparable items. If you notice any of these signs, seek transmission service in Madison immediately: A grinding noise when shifting gears; The gears slipping or difficulty shifting; The vehicle surges forward or backwards. Have Peace Of Mind, knowing that your new 4L80E Transmission has all the Updates developed by General Motors Engineers combined with the Latest Industry Advancements providing Unparalleled OE Strength and Durability. It’s in a 2000 suburban 2500 6. Installation is a matter of connecting a power, ground, ignition on, and a handful of other wires and connectors. 4L80E Transmission and Torque Converter. The RPMs will jump up but the ****** will not shift. Just thought i would share some of my experience with the 42RLE and PCM. 4L80e Shifting Problems. I could not even find a used a bad/worn out 4L80E case for $80, I think it was a good find. But upon further diagnoses it is not the converter. ” Nichols from Hughes says, “The 4L80E transmission family is the strongest GM overdrive transmission ever produced and installed in a standard passenger vehicle platform, and is arguably the strongest overdrive. good test to try is with engine OFF, disconnect transmission harness at right rear, and start engine. Symptoms of a Bad or Failing Transmission Oil Pressure Switch Common signs include the vehicle entering "limp" mode, having difficulty shifting, and its engine RPM being higher than it should be. I have a 01 2500 HD with a 408 and a T-trim at 12 psi. you can feel and hear the shift, its a pretty good clunk. Most MAFS problems were caused by K&N air filters coating the MAFS with oil causing the transmission to shift with higher line pressures. Any Transmission Guru's on the 4L80E. After spending about 3 hours internet researching ATF leaks in the 1992 Chev 6. Gm 4L80e transmission not shifting Hello, I'm a mechanic in the marine corp. You may have to register before you can post: click the register link above to proceed. I'm running a '93 4L80e with an Optishift controller. I have been chasing a hard shifting problem in my 4l80e for awhile now. Had got locked out of gear at high rpm many times, missed gears like crazy in that too unfortunately when trying to shift fast. Does anyone know what the problem could be?. It is now widely considered to be the best rendition of the finest overdrive automatic transmission ever produced. Could stop and restart and all would be good for 10-15 minutes then it would happen again. No other obvious electrical issues or performance problems. Progressive, meaning the shift becomes firmer in relation to throttle. 3 L engine (from 2002 Silverado) with a 4l80e transmission shifting hard from 1st to 2nd gear. Despite the advantages the 4L80E had over its predecessors, it still came with its problems such as losing the reverse gear and experiencing hard shifts. There's a good chance it's the neutral safety switch. 2-3 shift feel is somewhat controlled by band clearance (servo clearance). 700r4 shift issue 2nd to 3rd. Transmission will not shift into Drive or Reverse when warm. SHIFT INTERLOCK SYSTEM The shift lock system is designed to ensure the proper operation of the automatic transmission. Nonetheless, the latest parts have been designed with seeks to handle these problems. I have a 2500. Shift problems with 4l80E. The Transmission Rebuilders Network is the place where the industries best transmission rebuilders work together to help solve the most complex automatic transmission problems. Although you may have some of these symptoms / problems with your 4L60E Transmission, the repair solution may differ. PCS wont even talk to you for $600, they are $750. The driver must depress the brake pedal in order to move the gear selector from Park to any other range. The trans has an updated TransGo HD shift kit, drilled to the middle setting. thanks for any help 4l80e shift problems. It also slams into 4th at part throttle sometimes. Movement occurs almost instantly, unless a problem develops. and i will say this about additives DO NOT USE THEM once you put the chemical into the transmission it does not stop working until you drain both the torque and the trans. 2004 Chevrolet Silverado experiencing problems with transmission. Click on our transmssion controller link for more information. The 4L65e transmission that usually sits behind the LQ9 in its truck applications is not the best suited for this job. 10396 State Route 56 E. They should always be checked first if you are having a shifting problem. Need a little advice on a 4L80E repair. These are also known to have a premature failure if the unit hasn't been properly serviced. My 03 Silverado with the 4L60E has a hard 1-2 shift. I've replaced TPS sensor and still having same exact problems. I've checked fluid levels and condition, both are normal, fluid not burnt, nothing abnormal in the trans/engine mounts or u-joints. 2000 3/4 Ton Yukon 4L80e Shifting Issues run every shift is super hard. All gears seems to work. Most MAFS problems were caused by K&N air filters coating the MAFS with oil causing the transmission to shift with higher line pressures. It is only applicable to Jake’s Performance builds and customers. Codes can be cleared by. 3 L engine (from 2002 Silverado) with a 4l80e transmission shifting hard from 1st to 2nd gear. Bt good newsI think I solved 90% of my problem. A delayed engagement in the automatic transmission. It is now widely considered to be the best rendition of the finest overdrive automatic transmission ever produced. #SK 4L80E. The problem is that the lock up clutch goes bad. For a good quality basic controller that will shift and lockup the converter you can get a bauman controller (I've used several) for $600 and to my knowledge thats the cheapest controller for the 4l80e. Shift problem issues can. You Must Know These Common Symptoms of a Bad Transmission Solenoid We highlight the symptoms of a bad transmission solenoid, to help you effectively identify and solve the problems in your car's transmission system. When it shifts it is firm. A transmission can prompt a whining noise if the operating system has malfunctioned, the gears are not operating correctly or the transmission fluid needs to be changed. com FREE DELIVERY possible on eligible purchases. Shop right now. Toll Free (844) 298-6404. ailing transmission. If the Ford style is used, the 2 inputs not used for shift lever position determination can be used for datalogging voltage signals (temperatures, TPS, MAP, etc. I have a problem with my 4l80e transmission. I have a 1999 with a 6. Will a TransGo® Shift Kit® or a Reprogramming Kit™ make a transmission shift hard all the time ? NO, TransGo Shift Kit's® and Reprogramming Kit's™ have progressive shift feel. not temp related. then I still had the problem that the 50kPa at idle was causing a 50% lead reading, so the transmission would shift late and hard. The original owner replaced the trans at 100k and I took ownership at 190k. Just got my F150 project running last thursday the 8th. Well, I'm beginning to think my tranny might be on it's way out the door mechanically, unlike the initial thought of it being something related to the. It shifts very hard through all the gears and especially hard on the 1-2 shift. Shop right now. ez-tcu with 4l80e issues no downshift on WOT, and very hard shift from 1-2. usually with a speed sensor problem it will go into "safe mode" which is only first gear. After swapping it out it shifted terribly hard in all gears, but as I had checked the fluid level in the dark, I later found out the fluid level was way too high. Buy Shift Rite Transmissions replacement for 4L80E 04-UP Updated Transmission Valvebody MT1 Shift Rite 4L80E: Hard Parts - Amazon. 4L80E problem - hard shifting suddenly. I'm picking the car up up this. also if it turns out to be that none of this so far is it i agree with aaron on the tranny flush it will be a bit expensive but its worth it of instead of paying 1300 for a good rebuild of your tranny. No one seemed to have a solution or found a reason for TPS codes. 3 flex plate. The vehicle harness pigtail is provided to address connection issues that plagued some of the earlier 4L80E's. 4L80E trannies are known for their electrical gremlins. Does anyone know what the problem could be?. We also have the best aftermarket 4L80E 4L85E transmission controllers available. Buy GM 4L80E Transmission 1-2, 3-4 (A) and 2-3 (B) Shift Solenoids 91-up - 2 piece: Hard Parts - Amazon. Started a couple of weeks ago with harsh shifts from 1. I've replaced TPS sensor and still having same exact problems. GS-45D Ford C-4 Trans - Gear Shift Indicator Switch: Gear Shift Position Sending Unit for use with our 12 volt LED indicators. When going from park to either reverse or drive it slams into gear. You can also find other images like wiring diagram, parts diagram, replacement parts, electrical diagram, repair manuals, engine diagram, engine scheme, wiring harness, fuse box, vacuum diagram, timing belt, timing chain, brakes. Noticed that the torque converter wasn't locking up when this happens. a manual that you 'power shift' and/or 'pop the clutch' Boy Racer stuff and fine for a boulevard 'car' that is in the 3K-4K lb range. Rpm was also higher than normal when it banged into second gear and lock-up was`nt engageing when it should. Re: 4L80E shifts hard, your thoughts on the fix? Without a good scan tool it will be hard to proporly dianose this. You would think that Toyota would recognize this problem and correct it. Fluid color and smell Slightly dark reddish-brown. This list is merely a guide to the possible solutions. It was fine for a wile and then started to do the hard shifting as did the old transmission. Honda units have a unique problem with their gear position switches. We stuffed the 4L80E into the car using a TCI flexplate and a 10-inch lockup Street Fighter. A Brand New 4L80, 4L80E & 4L85E valve body. In other words it's not mushy despite its small size and high stall speed for street driving. Level 1 Mild to Firm Level 2 Firm to Hard! (most popular) Level 3 Very Hard Tire Burning neck jerking Shifts!. It really comes down to how much work you want to put into it. I kept a known good MAFS in my tool box. General Motors manufactures the Chevy 4L80E transmission, it is the strongest transmission made by GM. Pulled the codes and got P0741 (tcc perform. it shifts fine after that until you slow down enough to drop back into first. I was having the hard shifts between 1st and 2nd, as many others have described. When the vehicle sits on a grade it will roll backwards when in drive. The very first shift in the morning is perfect when the trans is cold. The 4L80E transmission is the advanced progeny of the legendary TurboHydramatic TH400 automatic transmission, and is based heavily on the 400 in both parts and strength, yet featuring an added overdrive gear, a lock-up torque converter and advanced electronic controls. No - showed way overfull when checked while running, hot level surface, like an inch past the top of the full hot line on the dipstick. it still used the lock up soloniod they had a couple of controllers to regulate the tcc. Like Glock said, if it also shifts really hard into second, the trans will need rebuilt of replaced. How is the 2-3 shift? Direct clutch also comes on in. No matter where we comand the 1-2 it wants to go to 6000-6100 hang there for a split second then shift. Simple push button control allows for manual shifting with multiple integrated mechanical and RPM based safety lock outs to inhibit accidental shifting into Reverse or Park. This is another really common problem with the 4L60E. The shift solenoids and lockup solenoid all share the same power supply. The result is greater horsepower and torque capacity. So I think there is some data you'll be able to check. If wired up exactly as the diagram at the bottom of this post you should have no problems controlling your 4L80e. All other gears shift normal. 2-3 shift feel is somewhat controlled by band clearance (servo clearance). Worn fluid equals poor shift quality. I'm putting a 4L80E behind the Isuzu diesel in my silverado. Hard shifts are often caused by higher than usual line pressures in your transmission which could be caused by sticking valves in your valve body or dirty fluid. Let's just say that when the time comes for my built 4L80E,he is going to be heavily involved. All other gears shift normal. The transmission shift solenoid facilitates smooth operation of gears. It is now widely considered to be the best rendition of the finest overdrive automatic transmission ever produced. 4l80E 1-2 shift problem. When it shifts it is firm. The gearing to move such a heavy load is a 2. Tip 2: Shift solenoid A refers to shift solenoid 1-2. Buy GM 4L80E Transmission 1-2, 3-4 (A) and 2-3 (B) Shift Solenoids 91-up - 2 piece: Hard Parts - Amazon. Hot Rod takes a close look at the GM 4L80E Automatic Transmission. Like Glock said, if it also shifts really hard into second, the trans will need rebuilt of replaced. On a truck that weighs +6K lbs and with several tons of trailer hooked up to will have much more stresses placed on the drive train when a shift kit is installed. The answer is the PCM is in complete control of every aspect of when and how the 4L60E shifts, Line Pressure and Lockup. All automatic transmission systems have a valve body which serves as the "brain" of the transmission. Now when at light to mid throttle, the shifting between all the gears is nice and easy almost not even noticeablebut at full throttle, the 1-2 shift delays a bit then kicks like a mule (I mean if you were holding a drink in your hand even with a lid it'd probably spill), 2-3 shift. good test to try is with engine OFF, disconnect transmission harness at right rear, and start engine. Transgo 91-05 4L80E Strip & Extreme Duty Shift Kit. And although you don't know it, I understand everything, including performance modification of the 4l80 trans. ailing transmission. or stuck off) and also P1870 ( Trans. This could easily be done by swapping around the entire engine computer and harness back to a factory style PCM,. Repeat this procedure from a standing start 3 to 5 times. Hard shifts are often caused by higher than usual line pressures in your transmission which could be caused by sticking valves in your valve body or dirty fluid. 4L80E Hard Shifting Jan 25 2012, 5:52am Hi, I have a 1992 silverado with a 4L80E trans. Simply drain and drop the pan and filter and it's right there. will not go into overdrive. That's a good point. 5 Turbo Diesel pickup and finding nothing of interest,. has all four gears but no lockup Has code Po894 slipping components will turn on chek engine light after a while. replaced bulb, also take of battery poles for a minute, and everything works great again, When you startup your rig, and service trottle soon light don,t light up, you know. The truck eases around great. I have a 4l80E and having trouble with the converter not staying locked up while at cruising speeds (70 to 80 mph). thanks Grumpy. GS-45D Ford C-4 Trans - Gear Shift Indicator Switch: Gear Shift Position Sending Unit for use with our 12 volt LED indicators. So I think there is some data you'll be able to check. Hard shifts are often caused by higher than usual line pressures in your transmission which could be caused by sticking valves in your valve body or dirty fluid. Smelled OK, no real burnt smell or anything. A Brand New 4L80, 4L80E & 4L85E valve body. Contact Us. 0Lwith only 115000kms on it over the last couple monthsthe4L80 transmission hasbeenhaving really hard shifts after drivingon the highway for 30-40 min in D4 the engine light comes on and the code p1870 comes up on the. These are the draft build instructions for the v2. The 4L60E transmission weighs 146 pounds dry, and 162 wet. In the mid-late 90's the GM trucks had a common ignition switch failure that would put the trans in default with no codes, sometimes intermittently. The 4L80E service will be $1250, not including any parts upgrades or shipping. It shifts very hard through all the gears and especially hard on the 1-2 shift. Top 30 Common 4L60E Transmission Problems and Repair Below is a list of common transmission problems with the GM 4L60E Transmission and possible solutions to repair. It was a common problem with those trannies. Could stop and restart and all would be good for 10-15 minutes then it would happen again. i changed the fluid and filter and the electric solenoids that regulate the shifting. the problem: 4l80e tranny sometimes slips out of overdive then shifts hard after coming to a stop and taking off. The completed 4L80E valvebody has new shift solenoids and pressure control solenoid. I have a 01 2500 HD with a 408 and a T-trim at 12 psi. Page 2- 4l80e shifting ? LSx Swaps. If a trouble code has returned repair as needed and recheck system. they did a test drive. #SK 4L80E. Chevy did something with the cars pcm and the problems went away. The original owner replaced the trans at 100k and I took ownership at 190k. Pictured below are just a few of the Updates & Upgrades that go into each 4L80E Transmission. I want the hard shifting Trans that don't have a manual valve body. The 4L80-E uses 2 shift solenoids, initially called Shift Solenoid A & Shift Solenoid B, later changed to comply with OBD II (On Board Diagnostics revision 2) regulations to 1-2 Shift Solenoid & 2-3 Shift solenoid. I kept a known good MAFS in my tool box. should go into reverse and in forward would be in 3rd gear all the time. After I have been driving for a while ( especially on the freeway ) it really bangs into gear pretty hard shifting from 1st to 2nd. 4L80E Rebush case, R & R only.

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