4L60E Messed up? Help Within

[Ginger]

Written by Dok Erik Von Broski

This will be of some help:



1. Slow, slipping or no reverse: low/reverse clutches are worn out, fluid leak in the reverse apply circuit, or broken sun shell. It is possible to remedy a fluid problem by removing the check ball from its cage in the case in the rear of the trans may help (must remove valve body), or adding a high-viscosity additive such as Lucas Transmission additive or other seal restorer product.

2. No 3rd or 4th gear: 3-4/direct clutches are worn out. Remove & Replace.

3. Sudden grinding noise with no prior warning primarily in 2nd gear, behavior in reverse may be abnormal; sun shell is fractured. R&R. Try not to run or drive or further damage could result.

4. No 2nd or 4th gear. 2-4 band is slipping. Servo seals may be damaged (can be fixed without removing trans. Otherwise, 2-4 band is worn out. R&R.

5. Trans shifts into gear harshly, 3rd gear starts, manual 2nd available but no 1st, no 4th, and no TCC lockup: No power to transmission, or trans is in limp-home mode. Check wiring, and make sure transmission electrical connector is plugged in. Easy fix.

6. No 1st or 4th available: shift A solenoid failed. Easy fix in the pan.

7. No 2nd or 3rd available: shift B solenoid failed: Easy fix in the pan.

8. No TCC lockup: Brake pedal switches improperly adjusted (always on), TCC solenoid failed (easy fix in the pan), TCC clutch worn out (must remove trans and replace TC).

9. TCC always locked: TCC apply solenoid circuit shorted to ground, TCC solenoid blockage (easy fix in pan), or TC broken (must remove trans and replace TC).

10. 1-2 Shift shudder at WOT; delayed or abnormal 1-2 shift: 1-2 accumulator piston cracked or stuck cocked in the bore. Easy fix in the pan.

11. Horrible noise in 4th and feels like the brakes are on: overrun clutches are applying due to a cracked or leaking forward piston. Overrun clutches will be worn out after 30 seconds of this behavior. Can be safely driven in D. R&R.

12. Soft shifting, gradual performance degradation: Leaking boost valve; clogged EPC filter screen, leaky seals. Transgo kit fixes first two without removing trans. Seal restorer may fix last problem, but probably R&R.

13. No forward movement in OD or D, but L2, L1 and R work: Forward sprag is broken. R&R. Try not to run or drive the car or further damage could result.

14. Extremely harsh shifts from P or N, normal shifts at WOT: EPC (Electronic Pressure Control) solenoid failed. Easy fix in pan.

15. Loud bang, grinding sound, loss of all gears, and a binding driveshaft: snapped output shaft. R&R.

16. Trans seems noisy when moving in 1st and Reverse, noise goes away instantly if you shift to N: Reaction planetary is worn out due to high miles or insufficient lubrication. Not a critical failure, but not a good sign either. R&R.

17. No movement in any gear: pump failure, or total loss of fluid. R&R, or refill pan and find the leak. If out of fluid, avoid running the engine until the trans is refilled to avoid pump damage. To check for pump failure, check fluid level with the engine off, then start the engine and recheck fluid level. If level does not go down when engine is running, the pump is broken.

18. Trans does not upshift out of first, speedometer reads zero at all times: VSS failure. Easy fix on rear of transmission.

19. Transmission does not shift automatically, only manually. Swap in a known-good PCM, check wiring, check other sensors.

20. 1-2 shift is delayed and harsh, may not shift into OD: Check TPS for smooth and linear electrical response over the entire range of motion. If not, replace.

 

[350VortecSSCT]

What about when it shifts, it makes a squeaky belt sound? wierd...

 

[Sully]

is number 1 slow reverse?

I think i fall under number 1 but not sure. I'm having issues doing 60. Sometimes the truck will shift between two gears trying to find the right one for that speed, but then it stopped doing that and just flat out couldn't do it. Giving it more gas just made it rev higher no difference in performance. Sounds like a slipping clutch to me I'm assuming thats the the torque converter. Then I get it back home (limping) and go to back down my driveway and nothing. The motor just revs. If I'm interpreting the first one on the list right, then I will go get some Lucas and see if it helps any. I did notice that the tranny seems to be leaking from the dipstick. My fluid levels are in the middle of the cross hatching.

 

[killagmc]

my trans lost second completely and instantly but still worked perfectly other than that whats that sound like. i know nothing about transmissions other than replacing them.

 

[dopeskater]

mine slips really bad in 1L. kinda makes a bit of grinding in reverse and doesnt move in D or OD when im not moving. once i get moving i can shift into drive or overdrive and get it to shift and if i floor it and it hits high rpms it just misses the gear? i was just gunna try to replace my tranny unless its a cheap or easy fix? let me know how much you think repairs could be. i think this is 13 in your list thanks

 

[MOBS]

I have the 4L80E in my 96 and it's just started today doing some weird stuff too.

1) When shifting from OD to D it makes a screaming sound like a hi-speed grinder wheel against steel and it also does it when shifting back to OD from D....does not make the sound once in either gear, just the transition of shifting....does not make the sound when driving either, only when manually shifting between those gears sitting still or rolling down the road. Doesn't seem to matter what gear it's in while driving(1st, 2nd, 3rd, OD).

2) It lost OD but has no slippage and had no slippage previous to losing OD, the only thing it did was sometimes it would feel like it's surging or jumping either back and forth between D and OD or the TC lockup was engaging and disengaging back and forth rapidly.

Not only is this a 4L80E, but it's the 6.5L, so it kinda rules out some of the issues mentioned above like the TPS. It also had an issue upon hard acceleration that would cause the rpm gauge to go down upon pressing the pedal down over halfway. It's got alot of little things wrong like that, I dont remember ever having a diesel with this many problems.

 

[slamd97step]

i have a 01 4l60e third flares up before it shifts seems to do it more often if its cold .the tranny just had brand new clutched put in it i bought the tranny with a blown third gear supposely .the tranny i originally had in my truck did the same thing and also second shifted pretty firm .i swapped valve bodys between the two and still acted up.i think both have the same problem.any thoughts?thanks

 

[92GMC]

i have no OD or D and it wont automaticly shift out of first. how do i replace the foward sprag? i dont have a clue what it is or what it does lol.

 

[Chris]

Find a reputable shop to rebuild it for you.

 

[SilveradoGuy85]

Mine in my 98 Silverado would shift really hard into 2nd after being on the highway for a few miles or going on a dirt/gravel road. I could stop it by pulling over, cutting the truck for for a few seconds and then cutting it back on. When I did that it would shift perfect. It also had just started to get where it would start off sluggesh for maybe 2 minutes then it would stop, it also would only do it the first time of starting up of the day, not every time I stared the truck.

First I went to Autozone for them to scan it for free, but of course it gives all this BS of what it could be. I then called a transmission shop and he said to bring it by so he can put his computer on it, he also said he wouldn't charge anything. Well, the only thing that came up was a bad mass air flow sensor. At first I wondered how that could cause the transmission to do that, but then I remembered how everything is wired together with the computer. Well I changed that out this past Monday (6/27) week this past week and so far so good with fixing both problems, even after test driving it on the interstate for about 30 miles and still shifted perfect after coming off the interstate and starting from a stop off the ramp. The old MAF sensor looked like it was the original one, especially since I've had it since '04 and this was the 1st time changing it. I did keep the receipt from the MAF sensor just in case it starts back up, even if it does I might keep the new one on there anyways.

So from now on I'm not going to Autozone or any other place where they use a diagnostics machine like Autozone has that doesn't specifiy what the trouble code is. Hopefully that transmission shop is willing to check my computer even if the transmission isn't giving problems.