Automatic transmission failing (ZF 4HP22)

[ALX3500]

Hey,

I've bought a European 325i from 1987 w/ a automatic transmission. After picking up the car, I drove home calmy for about 40km getting into all gears. When I pulled over for a re-fuel and wanted to drive off afterwards, the gearbox was not providing any traction. I could rev als high as I wanted, I did not get any response from the drivetrain. After a cool down of 15min, the tranmission re-functioned for about 1-2km (shifting up to 4th gear) but failed in the same way afterwards.

Same thing the next day: I drove without issues for about 5km (cold) and then the transmission failed.

Some diagnostics:
- ATF level = fine (relatively high but normal for a cold transmission)
- ATF quality = OK (proper color & no burnt smell)
- Putting 'm into P or N causes a rattling sound when running stationary
- Both D, R & 1,2,3 do not function if transmission fails

Can anyone give me some clues on how to diagnose in a simple manner? I do not have an equiped garage nor te proper experience :)

Thank you!
Alexander

[Morky]

I think my tranny makes the same rattling sound in P and right when the engine is at about 1800-2200 rpm in D. I have no clue what it is :( any help would be good

[whodwho]

Does not sound like your issue but a word of caution with 4HP22/24 transmissions, they have a flaw and you want to avoid r3vving in P&N after being in gear. The issue is after being in gear there can be residual pressure that keeps the forward clutchpack partially engaged and when you r3v it up you can burn up the clutchpack.

The symptom of a fried clutchpack is no forward gears and only reverse will work.

I would drop the pan and check the filter and pan for any excessive signs of metal or friction material

[wilholl]

Does not sound like your issue but a word of caution with 4HP22/24 transmissions, they have a flaw and you want to avoid r3vving in P&N after being in gear. The issue is after being in gear there can be residual pressure that keeps the forward clutchpack partially engaged and when you r3v it up you can burn up the clutchpack.

The symptom of a fried clutchpack is no forward gears and only reverse will work.

I would drop the pan and check the filter and pan for any excessive signs of metal or friction material

^^This^^

And a good service (fluid and filter change) goes a long way with these transmissions. Also, they are sensitive to the right amount of fluid.
The level needs to be almost perfect.

[supermansocks95]

Congratulations! Your trans is fucked! :D

[Morky]

What is the ideal amount of fluid for these trannies?

[wilholl]

Parked on a level surface...
Fully warmed up to operating temp (80degC).
Engine idling, transmission in Park or Neutral (do not rev the engine in park or neutral!!!)
Fluid should be between the top 2 marks on the dipstick

FYI: there are 2 types of dipsticks, short or long
The long dipstick has a lower mark for cold measurements (40degC)

[Morky]

Oh did I mention the car starts to overheat when standing still but it okay once you pick it up to speed? No burning smells though

[wilholl]

Oh did I mention the car starts to overheat when standing still but it okay once you pick it up to speed? No burning smells though

Probably a bad fan clutch

[Morky]

Thanks for the help guys!

[4x4_e30]

They can fail a couple different ways. I got mine back and forth to work for 6 months after "failing" I would manually shift into 1st and drive around till it warmed up, then spin it up to 6500rpm and shift into D and let off the gas then stab it a couple times... It would magically shift up through each gear then continue to work flawlessly until it cooled back down. My failure was due to a neutral rev at the Paul Walker crash site memorial drive. It doesn't burn any clutches out, but will blow the pressure governor apart then the little pieces spread throughout the valve body. The later models supposedly got it fixed but mine was a 1990 and still had the problem.

[Morky]

Anybody know what the best type of fluid to use for a 1990 auto car would be? Would it be different than the manual? It would also be great if anyone had a link to some help on how to change the tranny fluid itself :)

[whodwho]

They can fail a couple different ways. I got mine back and forth to work for 6 months after "failing" I would manually shift into 1st and drive around till it warmed up, then spin it up to 6500rpm and shift into D and let off the gas then stab it a couple times... It would magically shift up through each gear then continue to work flawlessly until it cooled back down. My failure was due to a neutral rev at the Paul Walker crash site memorial drive. It doesn't burn any clutches out, but will blow the pressure governor apart then the little pieces spread throughout the valve body. The later models supposedly got it fixed but mine was a 1990 and still had the problem.

I haven't seen a blown one, it typically is the quad seals(square o-rings) on the governor unit. You can fix this without pulling the trans out as the governor is in the tail housing.

[Morky]

Update: Car works perfectly after a tranny flush :)

[wilholl]

Well there ya go!!
Enjoy