Buick Lasabre Transmission

04 Buick with 94K flawless miles, couple of days ago, shifting somewhat rough. Driven 200 miles since then, shifting ok. Any of you transmission experts give me a prognosis, or advice, ?? Transmission has never been serviced.

you kind of answered you own question, depending of climate and surroundings, enough dust/etc can collect in trans to start to plug filter, bouncing around might move the clog around in fluid...i would have everything changed/check for piece of mind,,,it might be a relay for shifting,,

It is a great thing what clean oil and a clean filter will do for a hydraulic system.

It's hard to say since most transmissions are electronically controlled nowadays. My daughter had a Mustang that the torque converter lockup solenoid failed. It wouldn't unlock and when you tried to stop it was just like a straight gear, it would choke the engine. As has already been suggested, the filter may need changing. I had a 64 Dodge years ago that stated acting up when the weather cooled down. I pulled the pan and I swear, there was at least an eighth of an inch of sediment in the pan. Cleaned it up, new filter and fluid and she was good to go.

I had an '03 LeSabre. My son the mechanic printed out a bulletin that told about an electrical connection (plug) that would corrode and give failing transmission symptoms. Plugging and unplugging the plug was often enough to refurbish the connection. My '03 once acted like it had been shifted into neutral and coasted nearly to a stop when it started acting normal again. Only did it that one time.

Here's some of the text from the bulletin:

Applies to 1992-1994 Buick LeSabre Hydra-matic 4T60-E (RPO M13)

Condition:

Some owners may experience one or more of the following intermittent conditions:

Loss of drive (neutral condition) on highway while in fourth gear.

Erratic upshifts and downshifts at steady throttle angles without a malfunction indicator light (service engine soon) illuminated.

First and second gear only (no third or fourth gear)

First and fourth gear only (no second and third gear)

Cause:
These intermittent conditions may be caused by an intermittent short to ground on the "A" or "B" shift solenoid wiring between the ECM/PCM and the transaxle or an internal electrical condition in the transaxle. In most cases, these conditions are not caused by a hydraulic or mechanical condition in the transaxle. end of text

I don't want to imply that I'm a transmission mechanic. I know absolutely nothing about them.

Chased similar symptoms on my Stepdaughter's LsSabre...changed the fluid and filter which will probably fix yours, but it didn't help in this case; it would not shift into O/D then if you goosed it enought the Converter would eventually lock up and not shift back down at stops...couple days later I was fiddling with it got an check engine light...code said TPI (throttle position sensor) was at the U pull it getting parts for my Ramcharger project and grabbed a TPI outta a salvage LaSabre put it in and damned if the tranny wasn't shifting right. I assume that even though the engine seemed right it wasn't developing enough power to shift right. Read where a guy had the same issue with the MAP sensor on his Ranger...thought it was his Torque Converter

HI Pete,

The ECM (computer) needs to know where that throttle is so that it can adjust the signals sent down to the transmission.

Trouble is, those TPS sensor won't always throw a code (check engine lite won't come on either) when they fail.

Computer uses the engine rpm, the VS signal for road speed, Map sensor for how much load is on the engine, TPS and all the feedback in the transmission to determine how that tranny should respond.

Allan

Hi Larry,

A transmission service sure wouldn't hurt, but that's not what's causing your intermitent rough shift.

Like I told Pete below, there are a lot of things that effect how that tranny reacts.

Over and above all that however, on ANY GM automatic transmission issue, the first order of business is to check that fuel filter.

I'd sure keep an eye on it to see if it happens again and if it does, get it to someone who can throughly check it out.

Allan

DITTO!!!!! Its cheap enoguh to try anyways. Our 01 had 300000 some odd miles before the trans even showed any signs of acting up that wasnt a fuel related issue. Owners manual even says change fluid and filter at 100000, even on the "severve service" section.

Exactly,

If all is hooked up as it should be, there is absolutely NO WAY dirt can ever enter that tranny.

'Sides that, a plugged tranny filter is a completely different symptom anyhoo. :>)

Allan

Thanks everyone for the imput. Will see about the fluid change today. But have a feeling real problem lies elsewhere. I traded off a 98 intrigue when shop wanted 1800 to rebuild trans. Had a feeling later there was very little wrong with it. It was rough shifting when when warmed up good, if you were accelerating agressive.

Sorry - my Buick was a '93.

Drove old LeSabre till it would not go over 20 mph. Changed fluid and one day of driving fixed it up like new. Sometimes the Lord is watching over dummies like me. Dave