Am in the middle of taking Gearbox to pieces (1st gear syncro is unwell !!). Have basically got box stripped (It's a later unit - circa 1986 - model G28/10) - all the guts are now out of the case , and I'm starting to strip the components down ... BUT ....

How on earth does one hold the mainshaft from turning when trying to undo the rather large and tight nut which is at the end of the shaft ?? (looks similar to the nut on the earlier boxes which is "further along the shaft" !!) - we have de staked it as best as we can ... but it seems kinda tight !!

If I had a spare dead gearbox , I can see how I could possibly make a special tool by welding a bar onto a sliding sleeve and holding using that ....but I don't !!

ta in advance

 

I think you're looking for Porsche tool # 9142 and 9143(?)


There are some pics of me attempting to use it in post #21 of this thread:

https://rennlist.com/forums/928-foru...-pictures.html

Here's a better pic from the WSM, page 35-9:

 

Good info Rob but he has a Borg Warner box so it is different.

 

I had a similar problem holding the splined shaft during strip-down of a large outboard. I have a woodworking shop, so I:
- Cut a square piece of fir about 4" x 4" x 2 1/2".
- Drilled a hole thru the block (the short way) slightly smaller than the O.D. of the splines.
- Sliced the block thru the hole into two parts, so each part had a semi-circular opening on one edge.
- Put the block around the splined shaft, then clamped the block hard in a large vise. This pressed the fir into the splines without damaging the splines.
- Used a large wrench to loosen the nut while the vise and wood block safely held the splined shaft.
- Tightened the nut on the shaft using the same method.

I don't know how well this would work with your transmission shaft, but it sure looks safer than using a pipe wrench...

 

There is separate special tool pair for '85-95 gearboxes too. Info is in WSM.

 

I guessed that ... all we need now is a link to a workshop manual !!

(I have hard copy of older one with the "wrong tool" mentioned above in it)

The hole in the wood idea is exactly what I was planning to do next !! (After brief visit to local dealer to see if they have anything I could borrow .... not holding my breath)

cheers

 

http://www.2010.cannell.co.uk/manual...s_porsche.html

 

Great - thanks for that .... at least I know I was trying to hold it in the correct place ..... onto plan B !!

 

Just to kill this one - Plan B was to make my own tool .... pictured if it works .
Visit to local gearbox "fixer" to get scrap item out of a Merc Vito Van .. all I wanted was something with the correct teeth on it ... cost £5 , then to local blacksmith to heat and form a holder .... £15 all in for material and labour.
Back home , a few good tacks with the mig ... bit of paint
Worked a treat

Gearbox now built and tested .. and internal modifications (contrary to popular opinion in places on here) .. appears to have worked.
Will stay quiet until stopwatch proves point (or if it does not .... I'll just lie low ! )