ZF4HP22 harsh shifting revisted

[pundit]

I've asked this question before but as I haven't found a solution I thought I'd try once again. My 535iA (ZF4HP22) suffers from intermittent harsh shifts. It doesn't do it all the time and often it shifts very smoothly. It appears worse on downshifts as you are pulling up. It tends to hold onto gears and almost fights against the brakes finally downshifting with a clunk through the driveline when almost stopped. But the next time it will downshift and upshift just fine. I'm wondering whether it could be something like a dirty electrical connection to a trans solenoid or a sticking solenoid itself? I recently serviced the trans, Dexron III, new filter and gasket. I have checked the fluid several times and the level is spot on. As it is intermittant problem I am leading towards some kind of an electrical fault which, once correctly diagnosed, may avoid major work. - Any suggestions appreciated.

[Bellicose Right Winger]

Sound like a sticking spool in the valve body to me, but I suppose an intermittent signal from TPS could cause similar symptoms. Is problem more likely to occur with a cold transmission or does it occur after trans has been at normal operating temp for an hour? I'd drain and refill the trans fluid at every engine oil change for the next couple of oil changes. It's cheap, easy to do thanks to the drain plug and made a big improvement in the smoothness of shifts in my '90 535i. In my case improvement was most noticeable on cold trans and small throttle openings, warm shifts and shifts at more then half throttle were always smooth.

Paul Shovestul






I've asked this question before but as I haven't found a solution I thought I'd try once again. My 535iA (ZF4HP22) suffers from intermittent harsh shifts. It doesn't do it all the time and often it shifts very smoothly. It appears worse on downshifts as you are pulling up. It tends to hold onto gears and almost fights against the brakes finally downshifting with a clunk through the driveline when almost stopped. But the next time it will downshift and upshift just fine. I'm wondering whether it could be something like a dirty electrical connection to a trans solenoid or a sticking solenoid itself? I recently serviced the trans, Dexron III, new filter and gasket. I have checked the fluid several times and the level is spot on. As it is intermittant problem I am leading towards some kind of an electrical fault which, once correctly diagnosed, may avoid major work. - Any suggestions appreciated.

[Tiger]

i would start with tranny fluid and filter change... tranny flush is best where you completely change all your fluid... Majority of funky tranny problems are solved with this...I recommends Valvoline ATF for regular dextron...semi-synthetic is Pennzoil Multi-Vehicle... or full synthetic Mobil 1 ATF.

[Kalevera]

Probably just getting worn out if it's never been rebuilt :(

You just bought this car, right? How particular was the PO?

One of the things that you might do is have someone with a scanner see if there are any trans fault codes. I doubt there would be any -- probably just worn parts -- but it's worth a shot, eh?

best, whit