I have a 1995 Buick LeSabre Limited with 130,000 miles on it. When I picked up the car it leaked oil and trans fluid out of every gasket so I look the time to change all the fluids and seal up the leaks with new gaskets.

I changed the trans fluid, filter and properly purged the system from the transmission cooler so I am confident I got everything out of the torque converter. The car no longer leaks and I have put about 500 miles on the car since I got it.

I finally took it for a long trip on the highway. I noticed that if I take the car up to 60 mph and get it into overdrive, THEN slow the car down to 50 mph while it is still in overdrive and press the accelerator lightly the car will jerk and not accelerate smoothly up until it hits 60 mph again. It feels like the trans is trying to down shift from overdrive to 3rd gear.

If I floor the car it down shifts to 3rd gear with no problem, this only happens if I am going up the hill or gently apply the accelerator.

The car has no CEL light and I replaced the plugs and wires. The problem is definitely in the trans and only occurs between overdrive and 3rd gear.

Any idea?

I would start with checking the TCC solenoid switch. There'* a write up in techinfo about it. Might be a bit different from the write up but close. Sounds like the TC is going in and out of lock up.

Great write up, I figured this would be an internal solenoid switch or vac issue.

So test and possible replace or adjust, if not it looks like I have an internal solenoid issue

Thanks for your help, I will let you know how it goes

https://www.gmforum.com/showthread.p...olenoid+switch

I don't see it being a shift solenoid because there are only 2 of them, and you get each gear by a combination of the 2, forth is 1-2 on and 2-3 off. If 2-3 was the problem you would have issues with 3rd, if 1-2 was the problem you would have problems with first and reverse. If it was your PCS then all gears would be slipping a bit. The only other issue would be your 4th gear clutches.

Could the fix really have been that easy?

I pulled off the cover under the dash to inspect the TCC and brake light switch. I could not remove either of them with a 1/8 turn and folks in my office were looking at me funny laying on the floor of my car.

I notice that my TCC switch has a vac line and yours was totally electronic. I popped the hood and found the only vac line between engine and the firewall was disconnected and heavily dry rotted. I reconnected the hose and the problem seems to have resolved itself



dh2

Ya, it can be that easy. Good eye finding that. As I said, what you described didn't fit with a internal problem. Your Torque converter simply wasn't locking up.