: The 88 is down!!!

07-02-10, 10:17 PM
So my friend with the 88 went on vacation early this morning and broke down 8 hours into the road trip. The temp light would come on when he had it above 65 and go off when he went slower. But then, the car overheated. He stopped and let the car cool down, thats when he noticed a decent puddle of tranny fluid under the car. The tranny and engine were getting hot. He let the car cool down and took off again. Not too long down the road, it got hot and he said there was a pop and the car shut off never to be started again. The oil was hot and the tranny fluid smelled extremely burnt. Its at a shop but they didnt do much and we are bringing it home tomorrow so they wont have a chance to diagnose it, even though I would love for them to do a compression check because I dont have the tools to do so. So here's what I think happened...We swapped the tranny. The donor car was an 82 coupe with 3.42(or close) rear dif ratio. The 88 has 2.73(or close) rear dif ratio. I think the 200r4 from the 82 has a different final drive gear ratio then the stock 200 from the 88, this caused the engine to cruise at a much higher RPM than normal which caused it to overheat. I feel bad because I kind of told him this tranny should work fine for him.

I know there's not much that can be done for the drivetrain now but I hope the tranny isnt toast(though we probably wont use it again). We will be rebuilding the drivetrain in a very, very casual big block olds. May even keep it a roller cam(I'll start another thread) but this will be a little ways down the road. If anybody has any big block olds/small block olds parts they dont need, we will be needing them so please let me know if you have any. Its just sad to see one of the "crew" go down 400 miles away and feels like a slap in the face to pay $500 to get it home. We lost the 87 vin 9 last year to overheating and now this one. The 88 was the best out of the whole crew because it was such a Cadillac in every way. Smooth ride, quiet exhaust, leather seats and such style. It will probably never be the same.

07-02-10, 10:26 PM
Sorry to hear this, but at least she's in the hands of capable people.

The BB Olds will make that car!

07-02-10, 10:36 PM
Too bad it had to happen on a holiday weekend. Good luck getting it squared away.

07-03-10, 02:08 PM
The final drive is the differential.

The stock THM 200-4R has gear ratios of 2.74:1 (first), 1.57:1 (second), 1.00:1 (third), and .67:1 (overdrive), and there isn't a difference between the one used in the 4100 de Ville and the 307 Brougham. The 4100 cars had a lower final drive ratio (differential gearing) to compensate for the 4100's lack of power during acceleration.

07-03-10, 04:13 PM
Interesting. Thanks for the info, now I dont feel so bad. Its on the trailor making its trip back here. So it looks like his cooling system just wasnt up to par for the long trip.

07-03-10, 11:16 PM
I would be interested in seeing where the transmission fluid was leaking from. A problem in the transmission can cause an overheating issue in the engine; the transmission cooler lines run to the radiator and a transmission can get pretty hot when the fluid is low (because of slippage), which can over tax the engine's cooling system.

07-04-10, 12:57 AM
We will be at it in the morning. I'll let you know

07-04-10, 01:19 PM
So it looks to be a head gasket. Sweet smokey exhaust, a lot of pressure in the coolant system, brown coolant and a decent miss. The tranny looks to be leaking from the front seal but I didnt get a good look. The mechanic at the shop thinks that the TV cable wasnt adjusted properly and caused it to get hot.