Box jumping out of 4th

Ok so an actual VW question for once from me. I removed my 6rib box for a rebuilt 3rib with better suited gearing for the Corvair engine and it intermittently pops out of 4th. Sometimes not at all then it might do it 4 times in a row. Sometimes when lifting off and others whilst coasting, generally not when accelerating. I have adjusted the shifter plate both for and aft but still the same issue. The box is fine as it ran in another van perfectly well.

What is the procedure for aligning the shifter and plate as its been so long i cant actually remember.....

The shift bushes were changed last year along with the rods getting cleaned and re-greased so confident all is in order, clutch is new along with bearing etc

do these buses have engine and gear box mounts rubbers? (bit of a nice statement really!) or are they hard bolted in?
if there are soft mounts I'd be checking those.

When I used to work on old Porsche engines you used to get the gear box into second and then loosen off the gear stick assembly, do the same and then re-bolt everything - that was generally a decent starting point

Is the linkage coupling in good order?

Thanks lads, coupling was new a few years ago and looked in good order when the box came out. The 2nd gear adjustment is what I’ve always done, I recently moved the plate forward to see what that would do and the gear shift In general feels much worse and it still jumped out of 4th.

I will resolve this by shifting everything rearwards again and then look at the coupling to box joint

You went from an 091 to a 002….

Did your 091have the original bell housing or was it swapped to an 002 housing? With the OG bell housing a 6 rib box is a bit longer so that may have thrown the linkage length and engagement out??

Great shout. Yes I have the 6rib bell housing with the extra fixings to take care of the heavier motor, coupled to the 3rib box

creationblue said:

Great shout. Yes I have the 6rib bell housing with the extra fixings to take care of the heavier motor, coupled to the 3rib box

Click to expand...

Might just be enough to prevent full engagement.

And hopefully the 6rib input shaft. I would be looking at the engine mounts, to my mind when you lift off then the engine would try to move forwards so could pull it out off gear?

So in theory, move the shift plate back then try and make the gear shaft longer by moving the castle couple a little. Thanks guys you’ve been a great help

Hopefully a bit of fettling will sort it I had the opposite problem when I up graded to an 091 box, it moved the engine further back so I had to elongate the engine mount bolt holes and tweek the tinware so the motor would fit nicely lol

Think I cut the input shaft down by about 20mm but is was so long ago. @Bundy had this 3rib built with better gearing than the 091 so I slotted it in

Bit of an update on this in case it helps someone else, gearbox to engine lower nut was missing and the other lower one loose. May have forgot to tighten them when engine was out last year. I had a bad judder in reverse gear that started after the engine was removed and this is now solved that issue.

Fitted a solid billet gear shift coupling whilst investigating/rectifying the above then went for a drive, It did pop out of fourth on one occasion whilst descending a steep hill but that was it. Swapped the coupling back as it was far to noisy without the rubber inserts and have yet to test again...... Hoping after I have adjusted the shift plate again all will be good...