deweirdt

Hi,

Since a couple of weeks I've noticed that the gearbox oil is leaking and that I probably have to replace the seals (I don't know the correct word in english) so that the gearbox doesn't leak anymore.

Now I was wondering what type of gearbox oil I would need. Since it's very important that I'm using the correct type (thickness) for the automatic gearbox.

The car is a cutlass from 71.

Can you also tell me what type of engine oil is required and what type of oil filter I need?

Regards.

joe_padavano

"Seals" would be the correct word.

Automatic or manual transmission? The automatic has a filter, the manual does not. The type of oil is different also.

dan2286

He said its an automatic gearbox.

deweirdt

Yes, it's an automatic gearbox.

Do you think I also need to replace the filter?

Regards

joe_padavano

Ooops, sorry, I missed that.


You should replace the oil and filter every 24,000 mi (40,000 km) or so. Use Dextron III automatic transmission fluid. The seal that needs to be replaced depends on where the leak is coming from. If it's from the front, it could be the front seal or the pump seal. Either requires the removal of the transmission to access the seal. Other leak points (all of which can be repaired with the trans still in the car) are the rear seal, the trans pan gasket, the oil fill tube seal, the shifter arm seal, the governor cover seal, the vacuum modulator seal, the speedo cable drive adapter seals, and the cooler line fittings. You'll need to steam clean the trans and look for the exact source of the leak.

deweirdt

Hi,
The Dextron III I'm not sure that I'm going to find this here in Belgium. Do you know the thickness of that oil? They type or some other specs.

it looks like that the oil is coming out of the bottom from the transmission and the engine. (don't know the correct name in English) but it's the part with the bold to put the oil out of the engine and the transmission.

joe_padavano

Well, Dextron III isn't exactly oil, it's automatic transmission fluid. I'm guessing that most European cars (Opels, for example) use something similar.

Are you sure it's the transmission that's leaking and not the rear main seal of the engine? Trans fluid is red (or pink). If you are seeing brownish motor oil, it's the rear main seal. I'm sure it's difficult to tell exactly what color the oil is, given road grime, but try to collect some on a clean white sheet of paper under the car while it is parked.

deweirdt

When I look under the car I see indeed some sort of red oil. I'm sure it's from the gearbox. When I was checking this I also saw that the seal from the engine (I think I found the word "oil pan") was also leaking.

Both seals are draining in oil. And the oil is coming out of both seals (one engine oil and one gearbox oil).

Can you also tell me how much oil for the gearbox is needed? And also what type of oil I best use for the engine and of course how much?

Greetings

deweirdt

I just went to the shop and they don't have a DextronIII. I need something like 10w40 (this is a type for the engine oil (brand doesn't matter).

Do you know this?

joe_padavano

The engine uses SAE 10W40 (or 10W30 in very cold weather). The transmission needs Dextron II or Dextron III. I've seen ads for ATF DII and ATF DIII in the UK. These are Dextron-compatible fluids. It also appears that Ford-compatible Mercon V is also compatible and meets Dextron III specifications. Exxon and Shell sell this in Europe.

deweirdt

Ok I'll check again in the shop. I hope I can find this here in Belgium.

The SAE10 W40 will not be a problem.

Do you know how much oil I need for the gearbox and for the engine?
Do you have by any change the part number for the oil filter?

deweirdt

Hi Joe,

I found a shop that is selling the DexronIII and DexronII ATF.
Yesterday I changed the seal from the bottom of the gearbox and I'm preparing to fill it up.

Do you know how much full I will need? Is that 1L or 1Gallon? Just to know how much I need to buy.

Greetings

joe_padavano

The transmission uses about 3L of Dextron for a drain and fill. You will need a new gasket and should also change the filter at the same time. Once you fill it, you should follow the proper procedure to check the level - drive the car for a few miles to heat the trans oil and check at the dipstick with the engine idling and the car on level ground. Top off as needed.

The engine uses 4 quarts (about 3 3/4 L) of oil without a filter change or 5 quarts (4 3/4 L) with a filter change.

71CutlassSupreme

OMG!!!! this is the most useful post ever!!!
i just got back from a mechanic, i took my 71 cutlass in because it was leaking red tranny fluid. they had previously done the transmission fluid change, and the mechanic said that the new fluid is probably what aggrevated the seal causing a leak. and the mechanic said that the leak is coming from teh front so that he would have to remove the tranny to get to it. i wasn't sure if all what he was saying was true, but thanks to Joe's post i have no more doubts
out of curiousity. how long would it take to remove the tranny??
the guy quoted me 3-4 hours of work to do the job at $100/hr

ah64pilot

Joyce, what part of Houston do you live in? I live in Kingwood and would be happy to send you to a reputable shop close to me. I work at this shop when classics come in, more than likely I would be the one to work on your car. 3-4 hours sounds about right. I can also do this from home and only charge $50/ hr but I'm tied up this weekend and next.

71CutlassSupreme

oh man, that would be PERFECT!!! i'll shoot you a pm to get further details.

edit:
message sent
hopefully if it went through cuz it's not showing in my sent folder...