BMW automatic transmission

When I adjusted mine too tight the cam over centred and it would only shift at 6000 rpm. Granted it was a different car, but once I got it set properly it shifted great, and held shifts I redline.

From Dave's description it sounds like its upshifting way to early - so maybe the shift solenoids need to be looked at instead.

Rabin

Got a chance to take the car out to CORE for a little bit of a shakedown on Sunday afternoon. Allison did most of the driving but I drove just long enough to get a feel for the transmission's characteristics to see if I wanted to continue down the path to getting the automatic to work.

Initial impressions were that it really wasn't all that bad. Flew up the road that cuts the property in half and got pretty close to topping out 3rd gear. Found the suspension a little on the soft side for my liking, but the front will get JVAB 40mm shocks as soon as John finishes the 50mm stuff. On loose surfaces coming into a hairpin, I'd just take the lever and bang it from 3rd to 1st. Gearbox would pull into 2nd just fine, but it would take a rear lockup or low speeds to get it to drop into first. The course was rough on the exit of a lot of the hairpins, so in an effort to preserve equipment, I wasn't trying to fly through them on exit.

Biggest area of concern is that after just one lap, 2nd gear started to just free-rev and if bumped up into 3rd it did the same. Let the revs fall back to idle and put it back in drive and it would get moving again. At first I would've chalked it up to the transmission just not being up to the task of dealing with the power the engine was making because it seemed to happen just as the engine was hitting its sweet spot (~4500rpms)...but it seemed to just do it in 2 distinct places on the track and once at a 3rd location. All three spots were places the car was leaning enough where the inside wheels were getting light. Could it be possible that sloshing in the transmission pan could starve it of oil? (I don't know enough about these things to know if that's a reasonable guess.)

It honestly felt eerily similar to when the rear diff stopped limiting slip on the white BMW, where the car would feel like it was chugging and revving in an uneven manner. However the difference was, once the car had leveled back out it continued to essentially free rev with a barely perceptible forward movement.

Thanks in advance for any thoughts!

Dave

Add one quart oil and test again..

Quote
bttmotorsport
Add one quart oil and test again..

Thanks for the tip Jari! I need to figure out how to make a dip-stick for it.

I did bring some with me but was afraid that over-filling the trans might be even worse for it. Is that a myth? I know with my engines I've been told to go 1/2-1 quart over as sort of a poor mans accusump to help with starvation issues (with both the Evo and BMWs).

Found out from Grant this morning that Chumpcar has an exhibition class for cars that don't meet the $500 rule...hmmm.

Dave

I'd agree with Jari on adding a quart and seeing - but curious what the oil level is now?

The freewheeling in gear is one of the symptoms of a tranny going south on Peugeot's. Eventually you'll have no farward drive at all. I autocrossed my 505 turbo with 4HP22 and never had any issues under cornering load for what that's worth.

The fix / rebuild is a fairly simple fix that's well documented if you had any thoughts on keeping it. Pretty sure you'll 5-sp swap it - but if you do decide to fix it shouldn't be too hard.

I've only got a 4HP22 in a 505 TD wagon which is currently shifting fine, but I've got two spares that I want to play around with when I have some time so I can rebuild / upgrade it for a spare just in case - so I have checked into it pretty well.

A 4HP22 in good shape and the kick down cable set properly is actually a really nice auto transmission - finding one in good shape and set up properly is the hard part.

Rabin

I've got an extra dipstick/tube assembly that screws into the front of the tranny where the cooling lines exit...

Should be the same set up, and then just bend to suit if that helps. Or I can measure the two parts up so you have an idea of where to start with making one.

Rabin

Quote
bean
I've got an extra dipstick/tube assembly that screws into the front of the tranny where the cooling lines exit...

Should be the same set up, and then just bend to suit if that helps. Or I can measure the two parts up so you have an idea of where to start with making one.

That might be a real help! The tough thing is that it appears that when filling the trans from dry or wet requires totally different amounts of fluid, and if my trans is somewhat low, I'm not 100% sure that just draining the pan will give me an accurate measurement.

Currently the car has a dipstick tube and what looks to be a BMW engine oil dipstick with the plastic cut off (where engine oil marks are). What would probably be the most help is to know how high up in the trans pan the oil line should be. Then I can go find something locally that's too long and trim and mark it accordingly.

Thanks!

Dave

I might not be able to tell you the oil level in the pan as easy as I can measure the tube length and the dip stick dimensons. (tube and dipstick are off the spare tranny)

I'll measure the low and full marks from the top of the tube, and then you can compare the tube lengths and change the dipstick marks accordingly if the tubes differ in length.

I'll take some pics of dipstick and take some measurements so you should get damn close at least.

FWIW: http://www.disgruntledgoat.com/content/vehicles/dakar/ZF4HP22.php

Shows the fix for losing drive...

Rabin



Edited 2 time(s). Last edit at 04/15/2013 01:43PM by bean.