UN013 transaxle rebuild

Rob Bromfield

GT40s Supporter
I have recently acquired a UN013 transaxle (in bits) which being a hands on kind of guy (which is shorthand for "can't leave anything alone but gotta pull it apart to see how it works" etc, etc) I'd like to overhaul and upgrade.
Is there any info out there (apart from the ubiquitous Haynes manual) to help me?
Anybody have any hints/tips?
Where's the best place to get the parts?

Thanks in advance
Rob (This time I may've bitten off more than I can chew but what the hell how else do you learn?) Bromfield
ROB a man who may be worth a call and knows all about un1 type boxes is chris cole of mach 1 transmissions in telford a very nice chap and has built about half the un1 boxes out their his number for work is 01952222155 i know for a fact hes very bussy around eight or nine boxes to rebuild over the winter but worth a call he probably could supply parts as well

Rob Bromfield

GT40s Supporter
I must agree with you Chris Cole is a very nice chap and very busy at the moment.
I spoke with him last week about LSD (the diff not the drug)
and a long fifth gear.
I'd like to get some practice in reassembling the transaxle using the old components before I order the new parts but because Chris is so busy I don't want to disturb him with questions that are probably blindingly obvious. For instance the Haynes manual says that when replacing a gear you put the two halves of the needle roller cage on to the shaft first and then place the gear over them. I tried this but soon found that this isn't as straightforward as the manual says (not a big surprise) so what's the trick?
"when replacing a gear you put the two halves of the needle roller cage on to the shaft first and then place the gear over them..... so what's the trick?"

thick grease will hold stuff in place during assembly

Some other trans assembly tricks

When installing the two shaft assemblies into the case or case half, we're talking the input shaft and the counter shaft with all the gears installed, set them together on the bench and tie a shop rag around the center to hold them together and in position for assembly.

when assembling gears on shafts hold the shaft vertically in a vise using cardboard or brass jaw covers to pad the vise jaws. I even have some aluminum padded vise grip jaws.

Always use brass hammer, brass punches and mallets when working on tranny's, never a steel hammer.

You can use a press to assemble and disassembly shaft assemblies when necessary but sometimes it's easier/quicker to use a brass punch, bet never pound on gear teeth edges, always at the base of the gear.

Be careful of gear teeth, while they are very hard they are also brittle and can easily be chipped, typically when prying with a screwdriver. If you do get a small chip it doesn't necessarily mean the gear is junk but it will cause a tic, tic, tic, when the tranny is spinning. You can fix this by using a carbide bit die grinder to take the sharp edges off the chipped area.

After the case halves are put together, hold them together with about 3 bolts and bench shift the tranny running through all the gears and spinning the input shaft while watching for correct output shaft operation. It's easier to check at this point than after the trans if fully assembled and installed in the vehicle.

You can be tricked at this point if you've got a syncro that's was pushed hard onto a gear during assembly. The trans will seem to be locked in gear when it's in neutral. You have to apply a moderate amount of twisting force on one shaft while holding the other stationary to break the syncro loose. You can avoid this by making sure the syncros are all loose right before assembly.
...been reading this with interest...it all seems like black magic to me.....
Lots of admiration for those of you tackling a gearbox yourselves, I'd love to do it but don't trust myself.
My experience on these boxes is that a lot of people told me how they could do it.I only experienced the best ROI trough one guy who was dealer of Renault Racing Alpines in Belgium(retired) and Chris Cole who solved by bad investments of the past thanks to Frank Catt.


Rob Bromfield

GT40s Supporter
Thanks for the advice guys.
I went back to the bench last night and the gears went together as smoothly as anything! How I was having trouble I don't know!
Now that the gears are done all I need to do is sort through the pile of other parts and reassemble them in the right place in the right order /ubbthreads/images/graemlins/wink.gif