1999 x308 with ZF5HP24 transmission

car delays going into reverse most times, but not always.
When car starts up it reverses ok in morning out of garage,
but usually after that when selecting reverse it will delay
rngaging and kicks in... not smooth.

I changed oil foilter and tranny oil, but no difference.
Forward is all good.

Whats the problem?..is it the pressure regulator in valve
body, can it be repaired with one of those reaming kits if
I take the valve body out?

regards
Peter

 

You might try replacing the pressure regulator valve with the ZF upgrade first. Not difficult or expensive, but the problems associated with that are usually delayed shifting into 1st, I think.

http://jagrepair.com/images/AutoRepa...%20ZF5HP24.pdf

 

I have this exact same problem. I replaced the drum in my transmission immediately after it failed but not valve body. The jerking in reverse started after the drum replacement. My transmission has been jerking into reverse for maybe 3 or 4 years now, and hasnt gotten better or worse.

 

burmaz
you said you replaced the drum... is that the A drum???
Did you do the job yourself?? Im wondering how difficult it is to take that tranny out comepletely
if need be.
However it is my understanding that the pressure spike that causes the jolting originates in the
valve body. This pressure spike due to bore/piston wear or poor springs causes the pressure/delayed response and the result of it all is a fractured A drum.
I believe the A drum is for FORWARD Drive gears, but B drum is for reverse.

I am aware that there is a sonnax reamers kit that allows you to hoone out the pressure vlaves in the valve body to an oversize valve.. I am not sure if the Main pressure valve controls both foraward and reverse or if it separate. I need more research in the are.. If anyone has knowledge on this , I am all ears.

I believe this is the kit from sonnax, and it refers to the REVERSE B clutch situation on the page
http://www.sonnax.com/parts/1767

Does anyone have experience on it?
regards
Peter

 

It was the A drum that was replaced with a new update ZF replacement drum. A mechanic replaced it. He removed and replaced the transmission to do it. My center muffler was rusted in place so it had to be banged up to get the tranny out.

The A drum was replaced in 2008, I'm guessing about 45k miles ago. Reverse works totally fine in the morning, but when reversing for something like a U turn, it shifts slowly but smoothly into reverse. It will bang into reverse gear if I give it any gas before reverse is totally engaged however.

My transmission also sometimes downshifts slowly into first gear and will rarely bang into first gear if I slow down to a near stop, and then pull away. I just keep mine in sport mode to speed the downshift. I'm sure a valve body replacement would have fixed these issues. I've gotten used to it over the past 6 years though.

My transmission started really banging into first gear when my MAF failed. I had no CEL. It got a lot better when I replaced that.