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700r4 TCC issues ?

1402 Views 0 Replies 1 Participant Last post by  fast68
ok my 91 s-10 truck has recently developed a wierd issue when at cruising speed above around 45 or so.

it seems to be hunting around a couple hundred RPM up and down randomly at cruise speed and then it goes away for a few miles then comes back and does it a bunch more.

its not a gear it is in 4th gear and stays there just fine

it seems to only be a couple hundred rpm and as if the TCc is locking and locking back in again over and over for some reason.

i put in another fuel pump in earlier today to make sure it wasnt the fuel pump/pressure fluctuations doing it possibly, and well nothing changed..

it always starts right up instantly and runs perfect and strong.

one thing i did recently was replace the old toasted 191k miles original 02 sensor in which was bad according to code reading of the ALDL connector and it was horrible on fuel mileage in which is all better now it uses next to no fuel on trips and the exhaust doesnt burn eyes anymore.

before i replaced the sensor the trans did have a gear shift hunting issue where it wasnt sure whether it should hit 4th gear or not, at lower speeds, lower throttle position. and has been this way for a long time and from what ive seen posted it seems to be a common issue on these and many ppl experience it.
i dont know if its related possibly ?

CEL never lights up now anymore at all ever after replacing the 02 sensor.
no codes.
all good and perfect otherwise.
i took it on four separate 25 mile trips yesterday along the freeway and it did just fine other than this up/down rpm thing most of the time

what do you think ??

im gonna unplug the TCC and test that i guess. hmm.

i dont know what else it can be,

update: ok well i unplugged the TCC connector and it doesnt do this anymore at all, up down hunting is completely gone. i was always suspecting something to do with the TCC and i guess i was right.

is it going to be ok to drive it on the highway this way ?

if not then why not ?

maybe the converter clutch is worn ?

thanks for anything
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