zf auto reverse intermittent when hot

[themildbunch]

Since being given my diesel auto I've changed the ATF twice and had to adjust the throttle and kickdown cable...

Since the second ATF change (the ATF was pretty dark no totally black but old) it doesn't always get reverse when hot, after a run but will after a bit of a pause or moving the selector about a bit... After that getting reverse is ok again. Changes seem ok and I can't sense any slipping..

I haven't cleaned or changed the filter yet.

I used Dextron II on both occassions - Is this a common issue, caused by too high or too low pressure or temp or something else more 'terminal'?

I thought with auto boxes if the filters were getting clogged then any 'stickyness' usually got better as the oil warmed...

[docchevron]

a slightly over filled box can give some varied effects to how the box perfoms..
Worth changing the filter though, I doubt it's evre been done, they usually get neglected and even a partally clogged filter can cause all manner of oddities.

Also worth checking is the cable adjustment, if the quadrant doesn't quite engage strange things can happen

[themildbunch]

Thanks for that - yes it was a little over filled - i've drained some out and will double check when hot..

The other intermittent issue which is more worrying is it slips when sometimes when in 1st or low and accelerating hard from lights etc.. Seems like it goes into neutral / slips then when you let off the gas a little back to normal again... Kickdown seems to function normally at higher speeds though

This was an almost free car which had a described kickdown problem when bought but seemed to be just a very slack throttle cable and badly setup kickdown cable... Hope the box hasn't been damaged by too low a pressure or something..

[docchevron]

it's possible. If they are left to slip for a long time it does tend to kiil them, obviously.

Is the kickdown cable definitely adjusted right?

[kiwi]

Reading this got my interest since I now have an Auto to my collection.

Where are the filters located on the autobox you talk of? I changed the auto fluid recently but not any filters though, i did not think there was any.

Talking of the adjustment, one thing I still can not get sorted is being able to lock to gear positions 1 and 2, the display on the lever is slightly out so not sure if thats just coincidence or part of it?

Of course wifes car she wont let me near it so doing a proper diagnostic run on it is proving challenging.

[themildbunch]

it's possible. If they are left to slip for a long time it does tend to kiil them, obviously.

Is the kickdown cable definitely adjusted right?

I'd forgotten actually that this problem had existed for the seller too who wanted rid quickly for other reasons:

http://www.bxclub.co.uk/forum/viewtopic.php?f=1&t=15117

I hadn't noticed it as that bad but then I've been driving it more since the lucas pump episode on our TD.

When I got the car it was super slow and hardly moved on the motorway - no kickdown at all. The throttle cable looked new but not setup well.. the anti stall setting on the Bosch pump was much too low - I adjusted the throttle cable using the clip on the plastic adjuster and this fixed that but then the kickdown adjustment needed resetting. I did this using the RBSmith scans of the workshop manual:

http://www.thegreatbear.net/ebay/citroe ... manual.PDF

Pretty sure the kickdown is about right now, checked the measurements when hot and kickdown works pretty well and easily. In fact since getting the kickdown measurements just right it seems to slip slightly more easily in 1st now but you can pretty much drive it for months without slipping as long as you don't want to get away in a hurry or drive around Totterdown's hills extra fast!


Vale Street, Totterdown - Bristol by MG/BS4, on Flickr

Haven't done the filter yet but the PDF manual linked above seems to make it pretty straightforward and clarifies which bolts are which - Looks like you need to change the whole filter block and other gaskets. Doc, do you get a filter kit for this or just wash them out in petrol?

[themildbunch]

Just spoke to JPAT and the sump gasket and new filter are about £7 each so I think I'll get these and do this job too and change the fluid a third time be interesting to see what's in the filter and stuck on the magnets...

[docchevron]

I always change the filter, until they get to £1000 each it isn't worth taking a chance really, autoboxes are precious little things!

You'll likely find a fair bit of build up on the magnet, especially if it's been slipping for a long time.
Any way of rigging up a tacho and doing a stall test? That will give a fair indication of whats going on within..
I know that hill well!

[themildbunch]

That sounds like a fun test to do when the kids are running around!

I have one of those digital laser tacho's...

Think I'll do the filters first and try the stall test later - Is the the stall speed the same as the 'Locking Speed' of about 2200 rpm quoted in the workshop manual?

[docchevron]

lock speed is for the lock up clutch, but yeah, anymore than 2200RPM and you have problems.
No more than 10 seconds at full load either, the box gets incredibly warm stall testing it.

[Geoffrey Gould]

There is 1 band that has an external adjustment, worth a check. The little crimped sleeve on the kick-down cable has been known to be in the wrong place.
Anorak time All the bolts have torque settings.
G