5 speed box change and issue

[T3Aljezur]

Ok, before anyone else says it, I know, I know should have checked first
Anyway have just put in an ajp? box onto my AHU Tdi in my Doka
I had lunched my 4 speed but it was a bit abused and ancient
Anyway, my issue is it now jumps out of 5th when you apply anything like a bit of throttle. You can hold it in.
It's not a huge issue as most of my stuff is local, but would like it to work
I had sourced a 5 speed stick and associated bits to connect to the front of the main link to the box, above the spare wheel
It would not fit, completely different, so I used my 4 speed changer.
I can select easily all the gears, inc reverse, so I don't think this is the problem
Is there any adjustment to the links I can try first before pulling the box out and doing the syncro hub, which I believe along with the selector fork is most likely the issue.
Scuse the ramble and many thanks for any forthcoming assistance, and again, call in if your passing, Aljezur, Algarve that is
Dic

[Aidan]

worn mainshaft bearing / worn gear carrier allowing the input shaft to move forward under load, 5th gear moves away from the synchro and pops out, what was the drain plug magnet like ? Sludgy stem = big bearings worn

[California Dreamin]

Aidan is very knowledgable and I would take what he says as a good indicator .....he is the gearbox specialist on our forum.

Martin

[T3Aljezur]

all sounds feasible. exactly what it's doing.
Have not removed the drain plug yet but expecting sludge etc
gearbox changes smoothly and has no real noise
Aidan, obviously I'm here, your there.
I have a friend who used to build formula ford gearboxes and is happy to help me do the work
What parts would you recommend get done, for this issue, and generally for a 27 year old box.
Could you supply these parts and at what cost
Many thanks
Dic

[Aidan]

it could be linkage but generally if 1st and 3rd are ok then the throw of the linkage must be ok, worn engine and gearbox mounts could cause movement of box in certain conditions too - so check it over and drop the oil, if the plug is heavy then rebuild time
Get a copy of the Bentley manual and print out the relevant gearbox section and pass it to your mate and strip the box, then send me an email with a list of what you want for the rebuild _ I replace over £300 worth of bearings, synchro rings, seals, gaskets, fittings etc... as the minimum, you may chose not to, depending on what else you need to replace, eg fifth gear and the synchro slider may need replacing if they have been coming out of gear for a while and the fork may need replacing if it has been held in for a long time - that's another £100 of good used parts straightaway, but without having the lumps of metal to examine I can't say what you will need

[T3Aljezur]

excellent thanks for that Aidan
What you say makes perfect sense
I am going to replace mounts anyway, but my trailing arms need doing first along with 1001 other things, althought having the tdi makes it all worth while.
I have a bentley already so no worries there.
Two questions. How long does it normally take to source the necessary parts. I intend keeping the van, so spending now on the box I think is prudent.
Also, would the linkage I am using have any effect ie the 4 speed shifter set up and not the fie speed one
I'll send you a copy of the 5 speed stuff I have and maybe we could arrange something if they are any good to you
Thanks again
Dic