I just picked up a 95 Cutlass Supreme with a 3.1L and a 440-T4 transaxle and it won't shift into overdrive. It gets up to third and doesn't go anywhere. Has anyone had this problem? I'm going to flush the tranny, do a filter and fluid change, and throw in some Lubegard for good measure and see if it is a fluid transfer problem that might be due to old burnt fluid and clogged passages, but in the meantime, is this a common problem for the 440-T4? If so, is there an easy fix or am I going to have to throw in a tranny?

Thanks!

Welcome to the forum!

I'm far from the resident transmission expert, but it sounds like you may have something sticking inside that new fluid, filter, and Lubehard would take care of. How many miles are on that transmission? Do you drive it hard? How are your vacuum lines looking?

When the real gearheads get here, they'll probably have better advice.

Welcome to the forum.. While waiting for help, why dont u post an Intro of yourself in the New Members Section? Go ahead and make yourself at home in the Lounge. Nice to have u aboard

well you either have something gummed up and sticking or you have lost your 3-4 clutch and the rest will soon follow and do you mean a 4t40 trans?

a 95 cutty supreme regardless of motor should have a 4T60E with PWM TCC operation.

4th gear will get locked out if the PCM sees too high of a tranny fluid temp, which is a common issue due to insufficient factory cooling, i highly reccomend some type of external trans cooler piped in addition to the factory one built into the radiator.

I'll have to check the manual when I get a chance, but if 1 threw 3 work fine, I don't suspect clutches. Could be a bad solenoid. If it was clutches it would still shift, but slip. Have the car scanned for codes, some trans codes do not trip a light. Post those up and we will be able to help more.

4th would require shift solenoid A to be engaged.

1st requires A and B though....

Well here'* an update.

It is in-fact a 4T60E, I'm not sure how I got that wrong. I just bought it under the assumption that the tranny was bad or at least was not shifting past 3rd. I got the car, put a bottle of Seafoam Trans Tune in and drove it home. The car shifted alright, a little clunky, but went through all gears and overdrive. It didn't like low speed downshifts but I presume that might be due to having old fluid in there that'* lost all ATF properties. I'm going to drain the transmission and replace the filter and refill it with some good clean fluid, maybe synthetic, and put in some Lubegard and see how it goes. The previous owner said that it was stuck in 3rd and wouldn't shift into 4th/overdrive on the highway intermittently and then the last few weeks would not shift up at all. I experienced none of that and the trip home was about 60 miles on the highway. I'll post what I find when I take the pan down.

sweet deal.

if you're still having downshift issues, you could probably look at the vacuum modulator or it'* vacuum line as a culprit.

I made some suggestion on another thread you or others might find helpful....

My 3 cents worth: https://www.gmforum.com/showthread.php?t=297299...