help w/ front wheel drive trans?

[86 got boost]

I have a 96 riviera S/C I came to a stop, out of the blue when I pulled forward the trans slipped and shuttered, let off gas and back on was fine, does it all the time now...
but if I shift it manually in 1st or 2nd no problems, only seems to do it in drive and overdrive
reverse is fine, and no check engine light
trans fluid red and full
shifts fine otherwise...
ray

 

[86 got boost]

come on u all cant be stuck on 2004r, theres got to be a trans guru on here atleast...
its a 4T60E trans an nobody had seen or heard this problem before...

 

[gsgns4me]

Have it checked for trans codes even though the check engine light didn't come on. Some of the trans codes don't turn the light on until certian parameters have been met.

First thing that comes to mind is the PWM solenoid or pressure control solenoid failing, provided the thrans has been serviced regularly.

 

[86 got boost]

thanks for the reply,
going to check codes and pressure test coming tomorrow.
I drove today in manual 3rd and it was ok, only did it in overdrive its intermitant.
parked the car for 4 hours... and it acted up on the way home, worked ok in 1st an 2nd...

 

[86 got boost]

pressures were good

pulled code P1647--- boost, evap, TCC enable circuit

 

[gsgns4me]

pressures were good

pulled code P1647--- boost, evap, TCC enable circuit

If you have a buddy a dealer, ask if he would print off the diagnostics for that code and any TSB's related to that code or the symptoms you are having.

 

[gsgns4me]

pressures were good

You used a scan tool to increase and decrease pressures through the solenoid?

 

[86 got boost]

I was able to switch them on an off
turn the tcc off and seemed to be fine it jerked for a split sec. though...
turn off 1-2 shift and from a start its in 3rd gear, so I know there working and vise versa w/ the 2-3 shift
have a friend that works in parts at a chevy dealer
used a gauge to check pressures 79-85 in OD,D,3,2 an 158 to 170 in 1st
readings done all above 1000RPM no higher than 1400RPM

 

[gsgns4me]

My recollections on these has faded, but bits and pieces are fading back in. Kind of hard to remember without test driving, also.

I remember replacing quite a few valve bodies on these when I worked at the dealership for similar symptoms. Too much aluminum to wear out. There were serveral service bullitens giving guidelines on codes that may set and symptoms. GM's fix at that time was to replace the entire valve body (costly). The aftermarket now has repair kits for most of the problems. A local tranny shop probably knows more about the kits.

I also remember replacing quite a few PWM solenoids for similar symptoms, but that may have been on 4T65E's.

Make friends with the tranny guy at the Chevy dealer:tongue:.

 

[86 got boost]

thanks for the help very appreciated!...
ray

 

[Hacksaw]

Sonnax has a TON of valve body fixes for the 4T60E:
Sonnax Transmission, Torque Converter, Performance, Driveline Parts :: Transmission Specialties® :: General Motors :: 4T60-E

Now, the problem becomes WHAT valve train is causing this issue.

 

[Hacksaw]

Does this sound like your problem?:
"Intermittent Loss of Drive" 95-97 cars with 4T60-E (#67-71-64) - GrandAmGT.com Forum

 

[86 got boost]

kind of, but now there is no way I can pull away in OD, if in 3,2, after the 1st manual shifting and take off like grandpa its fine,
its like pulling away in 4th then I get convertor shutter let off and eaze it catches and goes,
now I just manual shift it from 1st.
Watched the temp when this happens and it shot to 240 from stop to stop, "a city block" thats not good so I try not to let it slip at all, kinda broke right now so it has to last. stays at 180' if I shift manually...
but it does sound like a valvebody problem...