banging auto

[Blanca]

Ever since I changed the ATF to Dexron II I have had some really big thumps from the transmission on changing, mostly in 2 to 3. Not something I experienced before changing ATF. As there are several Dexrons am I using the right one?

I recently had the Quibo, gearbox mounts and centre prop bearing replaced too.

[martauto]

I did hear that these auto boxes like the earlier stuff but cant help you with which, sorry.

Mart.

[Blanca]

Anyone who can?

[30316]

As far as I know all Dexrons are interchangeable. Dexron II was replaced by Dexron III probably in 90s. Are you sure the banging you hear is the auto box and not something come loose in the prop shaft area since you had some work done there?

[DanThe]

What fluid were you using before? Dexron 2 is old stuff and I expect you would have a hard time finding it, Dexron 3 is far superior and replaces pretty much any type of Dexron 2 from what I understand

Are you 100% sure you have the correct quantity in there?

[Blanca]

Hi Dan,
It had the original fluid in from what I gather from the previous owners service book,
Dexron II is on Amazon and listed as suitable for the E30.
As for quantity I may have a bit too much but not a lot, best advise was the worst that would happen is it would blow out any access.

I might shell out and get some Dexron III but of course it is difficult to get all the old stuff out without stripping the converter and draining that.

[Blanca]

As far as I know all Dexrons are interchangeable. Dexron II was replaced by Dexron III probably in 90s. Are you sure the banging you hear is the auto box and not something come loose in the prop shaft area since you had some work done there?

The noise is why I changed all the stuff.

[30316]

Hi Dan,
It had the original fluid in from what I gather from the previous owners service book,
Dexron II is on Amazon and listed as suitable for the E30.
As for quantity I may have a bit too much but not a lot, best advise was the worst that would happen is it would blow out any access.

I might shell out and get some Dexron III but of course it is difficult to get all the old stuff out without stripping the converter and draining that.

Too much fluid is also not ideal as it starts to froth as I understand it. You can never get all the fluid out as some will always stays in the torque converter. A few changes will eventually replace the old fluid. If you stay with Dexron and ideally the same make it will flush all of it out. It is also recommended that only fluid changes is not enough, you need to replace the filter as well. For that you need to drop the sump pan. Also with autos absolute cleanliness is vital.

BMW dealerships have a special equipment for changing which pumps fluid into gearbox may be under pressure to replace all the fluid which also goes through the torque converter. This process uses a larger quantity of fluid than the sump holds.