Citroen XM Forum

Those manuals are for SAAB and Eagle cars and I'm not sure of the age version. If known good valve blocks only have a single spring then I wouldn't worry.

Deans thread on his 4HP18 rebuild might be useful.
viewtopic.php?f=9&t=677&p=6392&hilit=4hp18#p6392

Many thanks Will and it was helpful to see Dean's earlier thread although I am still undecided about where to put the double spring, ie in the 2 or 3 valve! With regards, Matthew T.

Put it back where it came from, those drawings in the manual look wrong to me, but regardless, it worked fine until it didn't so just put it back as you found it.

D

Thanks for that Dean and I shall do as you suggest with the springs. I am now not sure whether to retry the original block or fit the spare, since in both cases all the main valves were thoroughly checked and found to be moveable. Perhaps I will start with the original block as I can fairly quickly check and change if required! With regards, Matthew T.

If it were me i would put the spare in, only because it will rule out the valve block, if it is not the valve block then, unfortunately, i would be questioning the forward drive clutch drum, not sure why it would choose this moment to break if it has but these things happen.

Fingers crossed the valve block swap cures it.

D

A lack of forward drive could be caused by an internal leak from any of the components that are pressurised when first gear (but not reverse) is engaged, for instance if an o-ring seal has failed.

I think only the specialist would be able to advise on that one unless someone spent a few hours studying the manual and even then may not have the experience to pick up on any potential fault, at a clance 1st gear selection uses the FWD clutch in common with all FWD gears and the low/rev clutch, which reverse also uses.
I dont think there is much in terms of seals between the valve block and clutch pack itself however i cannot remember ow the fluid is routed down the drive line to each clutch, it could be the slave seal in the clutch pack has popped rather than the basket breaking on the clutch retainer ring groove but the end result would still be the same, box out and strip down.

See what happens with the valve block swap anyway, we shall keep our fingers crossed for you Matthew.

D

I am definitely tempted to try both valve blocks Dean as the switching is quite a simple task once the battery box etc are removed. If there was a failed clutch presumably I would have some debris in the oil? The possible pressure leak to which Mike refers would I assume again point to the valve block or governor and I understand there are very few O rings and seals. Obviously I hope the valve block is the issue after my recent work, but I have also been reflecting on my mechanic's advice to revisit the governor. I noted in a further section of the manual that a leak from the governor outer metal seal can additionally cause loss of forward drive (see attached). Is it possible the seal may have broken during the fitting of the governor I wonder and I did experience some resistance, which I assumed was due to engagement of the splines? Regards, Matthew T.

The stator is part of the governor, is it not, or have I misunderstood the manual advice? Regards, Matthew T.

Yes the stator is the Governor, not sure which is the correct terminology, i did have copncern about your governor with the rubber seal in place of the metal one, wonder if the ring lands had worn and so the metal item was replaced with a rubber item to take up the wear.

Im a little sceptical though as this would not work fine and then suddenly not work but worth a look over ripping the box out.

If the FWD clutch drum had broken or the sela gone then you would have no debris in the oil, the clutch would not drag, or may not, it just would not engage in the first place although looking at other failures last night this seems unlikely in your case as in most cases the clutche do drag and fret the drum releasing metal debris if left unchecked for a length of time, again, i am short on experience in this respect so couldn't really say.

D