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View Full Version : E34 535i vs. 525i automatic transmission



Dash01
10-06-2009, 10:48 AM
Anybody know for sure if the early E34 automatic transmissions are the same between 525i and 535i cars?

Both cars have ZF 4HP22 EH transmission, but are they exactly the same?

Specifically, does the 525i have sport mode the same as the 535i?

How many pins on the 525i computer plug?

I've tried calling a noted ZF expert, but he does not return calls.

ryan roopnarine
10-06-2009, 11:47 AM
Anybody know for sure if the early E34 automatic transmissions are the same between 525i and 535i cars?

Both cars have ZF 4HP22 EH transmission, but are they exactly the same?

Specifically, does the 525i have sport mode the same as the 535i?

How many pins on the 525i computer plug?

I've tried calling a noted ZF expert, but he does not return calls.

i know for a fact that the m20 525i doesn't have the sport mode, and that is the one with the 4hp variant. i think that in that car the transmission is 4hp22h not 4hp22eh like yours, but that is just off the top of my head.

whiskychaser
10-06-2009, 01:30 PM
If the BMW part nos dont match then you have to ring BMW or ZF. I might risk a same year 325 and 525 but thats about it

genphreak
10-11-2009, 07:02 AM
M30 had ZF4HP22EH. Electro hydraulic (think sport mode)
Very probably they had different gearing on M20 4HP22s, (non EH), later 525 had M50 engine and sport mode, but in adding that, they also changed the entire tranny to a ZF5HP18 or a GM variant). E30 M20s had ZF4Hp22 but not EH model. No 4HP22 was supplied in the E36 (this too was M50) AFAIK, but u never really know with BMW production...

Dash01
10-11-2009, 10:38 AM
Thanks, all.

The reason I asked is (as you know from my other tranny posts) that I'm having 4HP22EH problems, and found a 4HP22 from an E34 525i, for $125.

Sounds like the basic 4HP22 won't work, as without the electronic over-ride for sport mode, it cannot properly communicate with the transmission computer.

Since I'll have to take my 4HP22EH out of the car anyway, I may tinker with it. I had trouble seating the TC, per earlier posts.

On installation of the TC, the tubular, tapered input shaft had maybe ~3/8" play in it, side to side, which seems excessive since it is secured by splines at its base (rear) end, and a couple of O rings along its mid-section. Granted, those O rings are a bit compressible, but I would not think that compressible as to allow so much side movement of the front tip of the shaft.

Perhaps I broke the pump (no pressure or flow at the radiator hoses) upon re-seating the engine to the tranny.

Or, perhaps while mating engine to tranny, I pushed the input shaft back (aft) into the tranny just enough to dis-engage the splines from the pump. I've read that the input shaft is secured by a snap ring, and maybe the snap ring dislodged and allowed the input shaft to slide back a bit, just far enough to dis-engage from the pump. If so, perhaps re-seating of the input shaft would fix the problem.

Anybody here ever taken one of these transmissions apart, and know how the input shaft fits properly into the pump? Does my theory about dislodging the input shaft have merit?

bmwrp8
10-11-2009, 01:50 PM
i know for a fact that the m20 525i doesn't have the sport mode, and that is the one with the 4hp variant. i think that in that car the transmission is 4hp22h not 4hp22eh like yours, but that is just off the top of my head.

my car is an '89 525i m20 i have a sport mode and my tranny is 4hp22eh