4l80e Strange Behavior..

caddy · February 23, 2008

I´ve got 1995 6.5 turbo diesel GMC Suburban. 230000 driven. I´ve owned this wehicle for two months soon.

Stange troubles appeared after driving few hundred miles. (Means I´ve driven few hundred miles with that now) Tranny does not work as it should. When driving ~50mph the tranny can´t decide which gear to use.. lock on and off.. And wehicle moves then really sticky, does not matter if it´s cold or warm. Revese sometimes does not react to accelerator pedal and sometimes it works fine. Is this kinda solenoid or sensor problem or what? There is only one trouble code, 36 (injection pulse width error(time long)). Does it relate to this problem? PMD/FSD is new and remote mounted. Fuel, oil and air filters are new and motor oil of course. Tranny oil is still the same, what there was, when I bought this Suburban. Oil level is allright.

I had 1994 6.5 ext.cab before and it moved much slicky with no this kinda problems ever.

Any ideas??

My english is not so good, but try to understand me.

I thank You beforehand!

Juho From Finland

xtrempickup · February 23, 2008

that trans is a fully electronicly controlled trans. i should know, I just sold my 95 6.5L automatic ext diesel. they act dependent on the motor. if the motor is functioning properly, as in everything, the trans will act accordingly. i had one that was sketchy and after i got the motor functioning correctly, the trans worked perfectly. hard to diagnose them, but could be solenoid related or could be torque converter related, those go bad in them and cause problems. mine would not lock up sometimes, shudder other times, get stuck in 2nd and other times run fine for weeks. if its been serviced a reputable trans shop should be able to drive it and diagnose what your problem most likely is. thats how i found out the motor function has a lot to do with the trans function on these trucks. That trans is a strong trans, but likes when things are correctly functioning with it

caddy · February 24, 2008

HI!

Thanks for Your ansver!

I`ve thought something like that. It is not necessarily trans` problem.

Where is TP sensor located? May it be the reason?

xtrempickup · February 24, 2008

HI!
Thanks for Your ansver!

I`ve thought something like that. It is not necessarily trans` problem.

Where is TP sensor located? May it be the reason?

honestly a factory shop manual would be your best best to locate stuff on that truck. i sold mine, actually happy its gone. if you dont have a manual yet, get one. are you a member on the diesel forums? good place for a lot of help, it was for me.

http://www.thedieselpageforums.com/tdpforum/

caddy · February 24, 2008

Now I´ve changed trans oil and filter. Oil was really dark, but there wasn´t any metal or other material in oil pan.

I noticed that accelerator pedal have sometimes problems with front gear too.. Engine ran only idle and does not react to acc.pedal. There was a little uphill and that is why truck does not moved forvard even with idle.

This is not trans problem anymore.. There is still no other trouble codes with 36.

xtrempickup · February 24, 2008

Now I´ve changed trans oil and filter. Oil was really dark, but there wasn´t any metal or other material in oil pan.
I noticed that accelerator pedal have sometimes problems with front gear too.. Engine ran only idle and does not react to acc.pedal. There was a little uphill and that is why truck does not moved forvard even with idle.

This is not trans problem anymore.. There is still no other trouble codes with 36.

36 has to do with the PUMP driver which you said you replaced and relocated. have you reset the codes and see if it codes back?