4l60e won't shift to 4th gear

[454hemi]

Hi everyone, I have a problem with my 4l60e tranny in my 96 Chevy Tahoe 5.7L Vortec.

My trans won't shift to 4th gear. When I put shifter into overdrive position and start acceleration trans normaly shifts through 1-2-3 gears. After that RPM goes to 3000 - 3100 but car won't accelerate no more and I get 62 mph and 3000 - 3100 rpm.

In shown in this video.
https://www.youtube.com/embed/t0zkwD9MMd4

In good case when all work fineI have 80 mph at 2500 rpm.

https://youtu.be/hAd4f2r_9sQ
After diagnostic I replaced TPS sensor and brake switch, but problem won't go away.

What could be the problem ?

[davester]

what do you mean by "after diagnostic"?  There were some codes?

[454hemi]

13 hours ago, davester said:

what do you mean by "after diagnostic"?  There were some codes?

I scan my car via GM Tech 2 and found brake switch open circuit trouble code. After that I replaced brake switch to new one.

[carkhz316]

Shift solenoid "A" may be bad. It comes on in 1st and 4th. Yes, that would imply you wouldn't have 1st either, which you may not and the truck could very well be taking off in second gear. The third gear shift you hear could be the TCC locking in 3rd gear in that instance. Barring that, there could be an issue with the 4th apply piston. This is the smaller silver aluminum piston that sits inside the bore of the 2-4 servo assembly.

[454hemi]

3 hours ago, carkhz316 said:

Shift solenoid "A" may be bad. It comes on in 1st and 4th. Yes, that would imply you wouldn't have 1st either, which you may not and the truck could very well be taking off in second gear. The third gear shift you hear could be the TCC locking in 3rd gear in that instance. Barring that, there could be an issue with the 4th apply piston. This is the smaller silver aluminum piston that sits inside the bore of the 2-4 servo assembly.

This theory sounds good.  Could it be that the A shift solenoid gone bad without raising any error code ? 

[carkhz316]

Yes it can fail without throwing a code. It's supposed to trigger a code, but seldom does. A lot of it depends on conditions met.

[burnunit]

Hello all, new member here, I posted this is other sub-section but this thread might be more appropriate.

Did a search but couldn't find a recent thread with similar problems so here we are.

Bought a used 1999 Tahoe with transmission that was supposed to have been rebuilt for my son.

He drove for about 10 months had intermittent issue going into 4th and down to third and back.

Suddenly I get call that its not moving at all, research after the fact tells me limp mode, I figured trans went bad and swapped for one out of a donor that was wrecked, didn't know about limp mode yet.

Swapped in the trans and truck drove better than the rebuild, actually went through all the gears, son went to get inspection but needed to put miles on for computer after it reset.

While driving it suddenly went to having nothing when put into drive, google research lead me to limp mode and this site.

What could cause the trans to suddenly go to limp mode while in the middle of driving?

Bad ecm? or bad shift solenoid?

Looking forward to getting some feedback and hopefully being a productive member to the board

Thanks

Burnunit

[KT Adams]

Hi, new member here 1997 chevy 1500 had trouble with tranny and put new one in now at random times it will randomly shift from fourth gear down to third when it is up to temp and have tried to figure everything out and still came to nothing except for getting to hot on tranny and i just need another opinion on what it may be