Transmission works when cold, but not when warmed up?

AHARTLEY

MEMBER
2005 BUICK LESABRE
3.8L
6 CYL
2WD
AUTOMATIC
230,000 MILES

I'm looking at a 2005. I'm told the transmission fluid is black. The car moves when cold but not after it warms up.
I've not actually seen the car yet, just asking questions.
I think that if the oil is brown and smells burned it's beyond a fluid and filter change.
Advice, I could be interested in buying this anyway.

Friday, April 4th, 2025 AT 4:00 PM

5 Replies

STEVE W.

MECHANIC
15,234 POSTS

Yeah, black fluid and the lack of motion when warm is an indicator that the fluid is gone, and the clutches are very worn. It also means that the seals in it are worn and damaged, so they don't work once the fluid gets warm. If the rest of the car is in very good shape and the engine isn't making noise and using oil a rebuild of the transmission would likely solve the movement issue. The thing there is that the state of the fluid and the wear in the transmission could indicate that the engine wasn't maintained very well either. Hard to tell without opening it up and checking it over.

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Friday, April 4th, 2025 AT 9:58 PM

AHARTLEY

MEMBER
118 POSTS

Yes, overall upkeep.
If I bother to actually go look at it, and if the price is right. Price will be the first hurdle for me.
Of course, there are several other things I would want to look at, but this was just a "word of mouth" starter type of thing.
One of the first things for me would be, Is the oil black.
I know to check the upper and lower plenum, the sub-frame bushings.

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Friday, April 4th, 2025 AT 10:25 PM

STEVE W.