Tips/How to change Auto Trans fluid

Reubo

Hello all, I’m going to be changing the auto trans oil and the gasket for the trans pan on my 1987 740 turbo and am wondering what people consider good fluid to replace with it, and also how much I will need?

Also wondering if it’s as simple as undoing the drain plug, removing the pan and replacing the gasket and then refitting it all and filling it up with the new fluid, or if there’s much more to it? I will have a more car savvy person with me but he isn’t a Volvo man so thought I should ask on here, cheers.

Massey165

Draining the oil and refilling the transmission with oil is not going to achieve much, removing the pan and cleaning out the muck is a must do. There is no shaft of gear correcting the engine to the transmission, it is the oil that does the work.

This is a 48 year old car, the transmission pan may never have been removed. Completing a full flush is the only way to do this job.ie drain the oil, remove pan etc, and refill the transmission, disconnect the top oil cooler pipe on the radiator, connect a hose to the opening, start the engine, pump out 1.5 L of oil, add 1.5L of fresh oil, repeat this step until the oil being pumped out turns red. Connect oil cooler pipe. Check level. There are many videos on youtube that cover this better than I can explain. This process will take 14 to 16 litres of oil. AS for the oil, check the specs and the manufacturers recommendations.

jamesinc

Massey165 excuse me, I am from 1987 and I am most definitely not 48!

@Reubo drain the pan from the drain bolt, remove the pan, clean it all up, ideally you got a gasket/filter kit in which case replace the filter screen and the two gaskets associated with it also. Coat both sides of the pan gasket with the sealant then reinstall everything. The pan bolts do not need much torque - however much you think it needs, it needs less than that. Watch the gasket as you tighten them, the moment you see it starting to squeeze out sideways even a tiny bit, it's tight enough.

Edit: to remove the pan, you have to disconnect the dipstick tube. This will test your willpower. Do not flinch, do not think "maybe it's seized". The moment you have that thought, the transmission knows it has beaten you. The fitting is ludicrously tight. You'll want a spanner on both sides of it so you don't damage the pan. Make sure the spanners are on properly so you don't round it off. I use two large shifters for this fitting.

The pan should have a magnet inside it, make sure to clean it off too (if the magnet is missing, glue a new magnet on)

I really recommend using Permatex automatic transmission sealant (Permatex 81180) on the pan gasket. It's very easy to over-tighten the pan bolts and then the gasket bulges and it leaks, the sealant makes it much more forgiving.

To flush the ATF, once you're all done with the pan gasket, add new fluid to replace whatever came out when you dropped the pan.

After that, most people disconnect the upper transmission cooler hardline from the radiator, and put a clear tube over it with a hose clamp, then idle the car and let 1L of fluid drain out, then put 1L of fluid in through the dipstick tube. Rinse and repeat that process until the fluid coming out is red and not murky.

You go through quite a lot of fluid doing a flush, expect to use 8-12L.

And yes you really can't get a similar result any other way. The torque converter in particular holds a lot of fluid, and the only way to get the fluid out is to pump it out with the engine.

You can also get a mechanic to do this flush, they do it the same way (except they have a fancier machine that pumps fresh ATF in at the same time as the old fluid comes out).

Remember, 1L at a time! If you start to see air bubbles in the fluid coming out, turn the engine off and fill the pan up again.

I use Penrite ATF FS

Massey165

Sorry James I am an old geezar and the brain only works sometimes. I have used this method on 2 x 940s and subaru outback, used 14 plus litres each time, you can stop at 12 litres and it will still be a far better life for your transmission.

Brad

When you disconnect the trans cooler line from the radiator be gentle. It's easy to break the cooler which is inside the radiator and surrounded by coolant. If it breaks coolant can get into the transmission. Been there done that, and got the strawberry milkshake.

Ramrodfunk

It's true " The fitting is ludicrously tight" on the pan. I found loosening the bolts holding the dip stick to the block relieved some of the tension at the pan
Don't remove the bolts from the block, just loosen.
A new gasket and filter can be found at most Auto shops because the gasket is identical to one used by Toyota. The Toyota model designation for the gearbox is A42D(?) but it's an aisin aw70./71. Image description

jamesinc

The Ryco version of that kit is RTK26