P38A Transmission Change

So today’s the day for finally swapping out the ZF22 gearbox on my P38.

So far so good. Prop shafts removed, crossmember and exhaust section removed.

Multiplugs and selectors disconnected.

About to attempt taking the transfer box and gearbox out in one, using engine crane and jack for support. Stopped for a coffee first, top bolts on the bell housing look like they could be a challenge.

Update at next coffee break!

End of day one, and have the gearbox and transfer box out (took them out as one piece.)

Replacements are currently separated, so question is... is it easier to put the gearbox and transfer bod back in together, or separately?

Thanks to @jamesmartin for suggesting the use of an engine crane the other week. That definitely made the removal much easier than it would have been just using a jack!

I've put my manual box in as one twice now. Not sure if the HP22 is trickier. If you're struggling then get it almost there and then nip it up with the bolts to pull it the last bit in.

Re-assembly question.....

Is it best to bolt the torque converter on to the flex plate (attached to the engine), then slide the gearbox on? I can't see any other way.

Or am I missing something, and the flex plate / flywheel should be able to come off the back of the engine?

Endeleus said:

Re-assembly question.....

Is it best to bolt the torque converter on to the flex plate (attached to the engine), then slide the gearbox on? I can't see any other way.

Or am I missing something, and the flex plate / flywheel should be able to come off the back of the engine?

Click to expand...

thats a sure way to break the oil pump
t/c must be full fitted to the box then box offered to the engine ensuring t/c doesnt slip forward, you should ensure the distance t/c securing lug sits from bell housing face is 1-2mm greater than the distance rear if drive plate sits from rear face of enginge, t/c is bolted to drive plate once box is fitted and t/c should spin freely and need to be pulled up the 1-2mm when fitting the securing bolts

I just re-fitted my auto box yesterday using my crane through the driver door to stop the convertor
slipping forward, I screwed a piece of timber across the bell housing to hold it in place then dragged
it unit underneath & got it into a good position ready to lift straight in, I jacked the engine up at the front
to tilt it down at the rear & it went straight in easiest box ive ever fitted.

Got it all bolted in filled with oil & started the engine it now has drive but the fluid is pi$$ing out
the new cooler pipe from the little red cap on the cooler fitting wtf bloody bleeding all over the drive
sickened me now

jamesmartin said:

thats a sure way to break the oil pump
t/c must be full fitted to the box then box offered to the engine ensuring t/c doesnt slip forward, you should ensure the distance t/c securing lug sits from bell housing face is 1-2mm greater than the distance rear if drive plate sits from rear face of enginge, t/c is bolted to drive plate once box is fitted and t/c should spin freely and need to be pulled up the 1-2mm when fitting the securing bolts

Click to expand...

Thanks. Lunch break, then out to give it a go. Have taken the round cover off the hoke in the bottom of the bell out a longer bolt in one of the holes, which stops the torque converter movjng more than about 3mm.

Going to put the box in first, using engine hoist and strop round the back, and jack under the front. Have put a couple of 4” threaded rods in the back of the engine to locate. Building up strength over lunch, then the moment of truth.

Well day 2 didn't go quite as well.... Got everything lined up, then found the torque convertor had slipped, so all needed to come out again.

Back to the drawing board for a future weekend. Any tips of getting the torque converter lined up with the oil pump would be greatly appreciated.. I found it a right sod, even on the bench.

I think the next attempt is going to be with gearbox and transfer box together, after making a bracket to mount to the four mounting bolts at the back of the gearbox (for the crossmember mounts). During yesterday's efforts, I manager to acquire a 12T high-lift trolley jack, so thinking now is to make up a cradle to fit that, and go for everything in one go..

Endeleus said:

Well day 2 didn't go quite as well.... Got everything lined up, then found the torque convertor had slipped, so all needed to come out again.

Back to the drawing board for a future weekend. Any tips of getting the torque converter lined up with the oil pump would be greatly appreciated.. I found it a right sod, even on the bench.

Click to expand...

It's a PITA.
The manuals show it being done with the box horizontal & a couple of threaded handles screwed into two of the bosses on the front of the TC. It does work, but I'd suggest removing small children & those of a sensitive disposition who might not appreciate the swearing from the area before attempting!
Last time I did my RRC (more or less the same box & TC) I hung the box vertically from an engine crane & lowered the TC onto the shafts. Went on instantly & easily. BUT there is likely to be a bit of fluid spillage from the TC unless it's a brand new one as they can't be fully drained. Best to try & tip out as much as you can.
As mentioned above, the TC must be fully seated & checked by measuring from a straightedge laid across the front of the bellhousing to the front of any of the bosses on the front of the TC. Mine's 51mm, full list here:
https://www.ashcroft-transmissions.co.uk/automatic-gearboxes/zf4hp22eh.html

I made up a small T shaped piece of metal which bolts to the threaded holes on the bottom round cover & sticks up inside to hold the TC in position.