4hp22 [revving]

[Notae30]

did not know till about yesterday that their is a probelm revving in netrual or park after going into a gear. is it truly that big of a probelm? trans isnt slipping nor running bad. but now im super worried about my transmission. i want to keep the auto trans. but want to boost and already gathering parts. will this mean i cant use launch control/etc without manual swapping? is there any other auto trans that will fit and be fine at 300-350 hp?
to clarify its a 88 535i with eco sport and 1/2/3
feel like an idiot now after learning this.

[gadget73]

Not sure when they finally fixed this, but there is a seal that was revised to fix this problem. If yours hasn't been done, probably would be smart to do it before it cooks.

https://www.europeantransmissions.com/B ... W.bull.htm

second entry talks about this.

[Notae30]

Not sure when they finally fixed this, but there is a seal that was revised to fix this problem. If yours hasn't been done, probably would be smart to do it before it cooks.

https://www.europeantransmissions.com/B ... W.bull.htm

second entry talks about this.

thank you

[Hit Man X]

Being an '88 you should have the updated pump with the A clutch (forward clutch) bleed off valve. This came along with serial number 175000 area. Yes, Teflon seals smarter. Superior makes a shift spring for these that firms up TCC lockup and shifts. You also remove an orifice in the channel plate and drill a tiny hole in the A piston. Orifice removed to make up for the internal hydraulic leak.

Modern friction material helps with torque capacity, you just need line pressure (to an extent) to keep from slipping.

When I build them to put behind a turbo M30 (like my 745s) I always do the six clutch A drum, late OD planet and OD sprag at minimum. Step further is an HP24 gear set from B to F clutch. All drops in and you receive an extra B clutch and extra C1/C clutch in addition to larger planets and a heavier C1/C sprag.

Hell, I would use the 24's A pack and pump with my 745 bellhousing (yes all bolts up) but I cannot find a damned torque converter to fully engage the pump. I need a 745 diameter one with the snout from the M70.

Why the 24's pump and A clutch? The frictions are 5" versus 3.9. Huge difference in torque capacity. If you are crazy, beta test a seven stack of the 3.9" A clutches. You use the thinner steels (1.2mm I think) and stack up with a wave plate at end. The pack is static in all forward gears so I cannot see it not working. I plan to on my next build in the 11/84 745 unless I sort the converter issue.

[Mike W.]

Being an '88 you should have the updated pump with the A clutch (forward clutch) bleed off valve. This came along with serial number 175000 area.
...

Wow. I've been in them a couple of times and know a little bit, but Hit Man X really seems to know his stuff.

[Notae30]

Being an '88 you should have the updated pump with the A clutch (forward clutch) bleed off valve. This came along with serial number 175000 area. Yes, Teflon seals smarter. Superior makes a shift spring for these that firms up TCC lockup and shifts. You also remove an orifice in the channel plate and drill a tiny hole in the A piston. Orifice removed to make up for the internal hydraulic leak.

Modern friction material helps with torque capacity, you just need line pressure (to an extent) to keep from slipping.

When I build them to put behind a turbo M30 (like my 745s) I always do the six clutch A drum, late OD planet and OD sprag at minimum. Step further is an HP24 gear set from B to F clutch. All drops in and you receive an extra B clutch and extra C1/C clutch in addition to larger planets and a heavier C1/C sprag.

Hell, I would use the 24's A pack and pump with my 745 bellhousing (yes all bolts up) but I cannot find a damned torque converter to fully engage the pump. I need a 745 diameter one with the snout from the M70.

Why the 24's pump and A clutch? The frictions are 5" versus 3.9. Huge difference in torque capacity. If you are crazy, beta test a seven stack of the 3.9" A clutches. You use the thinner steels (1.2mm I think) and stack up with a wave plate at end. The pack is static in all forward gears so I cannot see it not working. I plan to on my next build in the 11/84 745 unless I sort the converter issue.

thanks alot man. really helps.

[Hit Man X]

Glad it helps guys. I have only built 6-8 of these so certainly not a bigtime svengali on them, but sort of figured out what works and what does not.

Oh, and stop using OD when in the city. It beats on the E drum when F clutch applies.

Also, 745 spec 3HP22s have near identical gear sets as the V12 cars and usually you can pick up them for hardly anything. They make for a great budget HD unit to install into a 4HP22 case.

[richardb]

Lots of great info in this thread. I can confirm that the neutral or park revving can ruin the transmissions.

1984-1987 models were also prone to transmission failure when smog checked by revving the engines at high idle for several minutes. My 533i's transmission was replaced in 1994 at BMW for free because of this.

"...BMW will repair the transmission free of charge for a period of 10 years from date of the original purchase or 100,000 miles..."

I'll check the number on my trans plate, I wonder if it was updated with the revision being that it was replaced in 1994.

[Mike W.]

1984-1987 models were also prone to transmission failure when smog checked by revving the engines at high idle for several minutes. My 533i's transmission was replaced in 1994 at BMW for free because of this.

I had an 84 733 which I had smogged a couple of times. In Calif at least the smog techs seemed to know about it and only tested it at idle, not idle and 2500 as was the standard at the time.

I forget if it's already been mentioned, but supposedly if left in park after being off more than 30 seconds, and not moved out of park, it would not cause a problem. Not that I'd be willing to make that test...