Tranny trouble

[matuva]

Yesterday, a buddy told me he is experiencing trouble with his tranny.

Being on a 1995 K1500 Silverado, I believe the tranny is a 4L80E.

Problem is:

his wifey was cruising in D. Slowing to engage on another road at a cross, she realised the tranny looks like the TCC stays locked.
She continued slowing down and then heard a strong noise, whilst the TCC disengaged.

Now, the trans works fine, shifts up and down perfect if you select position 3. If you put on D, he says the truck is sluggish. He can't tell me if this is because the converter is slippering, or if it is like the TCC immediately lock in higher speed.

Any thought?

 

[bk95td]

Most auto trannys with lock-up have a fail-safe that will unlock the converter at around 5 mph if for any reason the electronics don't unlock it. A sticking TCC solenoid could do that. A scan tool should tell if the ecm is commanding TCC.
This place sells high quality kits with all the internal electronics for around $150 http://www.electricaladvantage.net/4l80esolenoidmasterkitwinternalharness.aspx
This is a thread I did on the install of one of the kits:http://www.thetruckstop.us/forum/showthread.php?29925-Installing-A-Electrical-Kit-In-A-4L80E

 

[matuva]

Thanks for the input and the links Barry

 

[3500GMC]

X2 on the stuck TCC solenoid.

 

[Chief915]

X3

 

[orrum]

Grounds? Thats all I really am allowed to speculate on. Newbie here but to me sounds like mine when the ground strap came loose and it was a slow struggling dog.

 

[matuva]

I checked for codes and found DTC 68 Trans component slipping. :skep:

converter? sensor somewhere else?....

 

[bk95td]

The ECM compares the engine rpm with the input rpm and output rpm. Any mismatch in speeds indicates a slip somewhere. The TCC solenoid is a common failure.
When I put the complete kit in my tranny , all I really needed was the 1-2 shift solenoid. At over $50 for fluid alone, I didn't want to have to dump out all the fluid again to replace another component. My main wiring connector was weeping badly also. Everything in there is 16 years old and run in pretty hot conditions.
Check for filings built up on the input speed sensor and output speed sensor. They are magnetic and attract metal filings. Doesn't cost any thing but time. Only takes a couple minutes to clean both.