First time doing ATF change myself - any tips?

Hi everyone,

Me again…I’m going to tackle changing the automatic transmission fluid on my 85 Olds Cutlass Supreme, has the V8 305 engine. I believe it’s a 3 speed tranny, have to double check the shape of the trans oil pan and compare to the photos in my Haynes manual.

Just wondering if anyone can offer any tips for the oil change…I’m a bit nervous, don’t want to “hurt” anything or do anything wrong. The car shifts great and runs (mostly) great, and I don’t want to disturb that. But it has 220k kms, and I don’t know when the trans oil has been changed last…

I’m an engine oil change, brakes, and other small jobs kinda guy, to give you an idea of my mechanic ability…but wanting to learn a lot more.



If you can do those mechanic jobs you can do the trans fluid change with no problem, other than the trans fluid being a messier job.
Use a wide pan and leave a bolt in roughly each corner of the pan. Then remove one bolt followed by another. Slowly. This will allow the pan to start tipping and it least makes it not as messy as it could be.

Examine the pan for any debris. A blackish coating can be normal, but you do not want to see brass flakes and spoonfuls of black junk in there.

When you remove the filter make absolutely sure the old rubber seal on the filter comes out with the old filter. Oil the new seal on the new filter and make sure it seats when you push the filter into place.
Add fluid, start it, shift through the gears a few times, and then recheck.

(I would advise that you stay away from filter kits that use cork gaskets. The cork nowadays is pretty lousy and I’ve seen numerous transmission leaks caused by the fluid actually seeping through the cork itself. Use the cellulose ones and do not overtighten the pan bolts. Snug them up and after running it a bit resnug them a bit more.) Hope that helps.

The only difficulty I faced the 1st time doing this was putting the back in. Yes, you guessed it, I took the original off without thinking twice. I hadn’t jacked the car and space was tight so took couple of twists to figure the right position for the filter. Apart from that it was a breeze; Oh and by the way mine has a drain plug that makes life so much easier.

To avoid a BIG mess, try to drop one side of the pan first as OK suggested so you can control the flow somewhat…I leave 2 bolts in, across from each other, then loosen ONE of them so the pan tips down from one side…

Check the bolt holes in the pan for being deformed by over-tightening the bolts. If they are dimpled up, you can support the edge of the pan with a block of wood and hammer the dimples down flat (with care) so the pan mating surface is once again flat…

Wear old clothes, put down lots of newspaper, and keep your mouth closed. :slight_smile:

Thanks for all the tips guys, especially the cork part and the keeping my mouth closed part haha :slight_smile:

I’m picking up the kit today, no cork gasket…will be doing the change tomorrow and I’ll post back to let you know how it went.

Most, if not all, quality brand tranny kits now come with rubberized gasket or rubberized (cork) gasket. You know you have one because the gasket is half-folded inside the box, plus box is small compare to the old cork gasket which had bigger box to accomodate the cork gasket laying flat. The old cork gasket is history. Haven’t seen one for long time.