ATF Filter M20 525i

[uscharalph]

So I'm starting to plan out the initial stage in flushing my transmission. My plan is to change the filter, gasket an o-ring and just replace whatever fluid is drained in that process. Then run the car 3-5,000 miles(?) and do it again, maybe this time flushing all the ATF. I'd like to use whatever's the best for my car. I'm not too worried about this cost, but don't want to waste money. Should I say use one type/brand of ATF on the 1st change (Do I need to worry about mixing with what's in there)? And then go to something else when I do the full flush?

Is my transmission the ZF HP22 or the ZF HP24 (Or how do I find out)? I believe the part numbers are the same for the kit in both models.
screen / filter - 24 31 1 218 571
gasket - 24 11 1 217 082
o-ring - 24 34 1 217 437
Are there any other parts I should be ordering?

My engine bay has a dipstick for the ATF so I don't need to fill the ATF from the bottom right?

[Dan in NZ]

It's the 4HP22. The 4HP24 was the strengthened version used with the V12 sevens.

[JonE]

Hi Ralph,
On my 325iC I replaced the gasket, filter and ATF fluid and just used the Dexron III, or whatever it's supposed to take. Worked out pretty well, just make sure you get those bolts torqued correctly, might have to tend to them a couple of times to get it right for no leaking. I think I also had to retighten the dipstick connection nut. I've thought about going with the synthetic fluid next time, but still undecided.
On the 535, shortly after I got it, I just did a drain and refill, again with Dexron III ATF. I let it drain for awhile and measured how much came out and just put that much new ATF back in. checked to level and adjusted until it was right. I think I'll probably do a filter/gasket/fluid change in another 1-2 thousand miles.
Yes, you should be able to fill with the dipstick hole.
Good luck, man.

[uscharalph]

Thanks man, I can't wait till I do this. I almost seems as if since I did the spark plugs, wires, distributor and rotor and switched to Mobil 1 synthetic, the engine is running so great that the transmission is holding it back. I'm probably feeling something that's not there. I've never had any problems with the transmission.

[632 Regal]

I found royal purple to have a full synthetic dex 3 for a very reasonable cost, was like 50¢ more than the regular dex 3.

[JonE]

Jeff,
Is that stuff actually called "Royal Purple"? Good tip, I'll have to take a look. I assume it is ok to mix it as you really can't get all of the old stuff out.
Ralph, next you better get that EAT chip, then you'll be about as good as you can with the M20 engine. I actually didn't notice any appreciable performance difference with the tranny fluid change, maybe just a bit smoother, kinda like after an oil change. Maybe you just "feel" better knowing it's been done!

[uscharalph]

Jeff,
Is that stuff actually called "Royal Purple"? Good tip, I'll have to take a look. I assume it is ok to mix it as you really can't get all of the old stuff out.
Ralph, next you better get that EAT chip, then you'll be about as good as you can with the M20 engine. I actually didn't notice any appreciable performance difference with the tranny fluid change, maybe just a bit smoother, kinda like after an oil change. Maybe you just "feel" better knowing it's been done!
I'm saving money as we speak for the Eat Chip.

[Kalevera]

Royal Purple is good stuff. Inexpensive and excellent quality. We started using it at the shop after Redline started price gouging (aka -- costs us to distribute the stuff, versus being able to recoup costs or make a dime on it).

Ralph, I'd use it over the generic dexron III.

best, whit

[uscharalph]

Royal Purple is good stuff. Inexpensive and excellent quality. We started using it at the shop after Redline started price gouging (aka -- costs us to distribute the stuff, versus being able to recoup costs or make a dime on it).

Ralph, I'd use it over the generic dexron III.

best, whit
So when I do the initial tranny work, changing out the filter etc., I'll only be taking out about 50% of the old fluid. Is it OK to mix Royal Purple with the remaining 50% of old fluid till I do a complete flush?

[Bill R.]

7 to 8 bucks for the atf, besides that any quality brand of dexron III mercon is already 50% synthetic. Thats part of the qualifier for mercon and dexron III, they are considered a semisynthetic. I buy and use castrol dexron III mercon in my car and my customers cars that take it. Its sells for about 2.25 at the most, frequently a lot less when its on sale somewhere.





I found royal purple to have a full synthetic dex 3 for a very reasonable cost, was like 50¢ more than the regular dex 3.

[Bill R.]

torque converter is 7.5 liters, when you change it the specified amount is 3.0 liters, when you change the filter you'll get a little more out of it, probably 3.25 to 3.50 quarts when you fill it back up. You can mix whatevers in there with royal purple or any other brand of dexron/mercon atf.




So when I do the initial tranny work, changing out the filter etc., I'll only be taking out about 50% of the old fluid. Is it OK to mix Royal Purple with the remaining 50% of old fluid till I do a complete flush?