UN1 Gearbox drive shaft oil seal / breather

Dave Bilyk

Dave Bilyk
Supporter
My car has a renault un1 gearbox, I notice that it has a small leak from a drive shaft seal (lock ring side), there also doesn't seem to be a breather (both sides are plugged). My two questions are; Is the shaft seal easy enough to change? and is there a specific breather used for this box?

regards
Dave
 

Dave Bilyk

Dave Bilyk
Supporter
I removed the drive shaft and the lock ring / seal today. It was easy enough, I only had to disconnect the top and trailing arms to slide the driveshaft off.
Prior to this, I drifted out the roll pin which came out broken in two pieces. I am now wondering whether the leak is not really the seal, but oil finding its way along the spline and into the centre of the roll pin. Anyone have any comments / experience on this?
I will of course replace the seal anyway.
regards
Dave
 
Andy of the old GTD recommended that these roll pins be instaled with RTV and once installed squeezed More RTV down the center of the roll pin. Any sealing you do will be good.I installed mine that wqy several years ago and to date have not had any leaking or seeping.
 
Dave,

The breather on the UN-1 is located on the bellhousing end of the casing, on the top, just where the bellhousing bolts to the trans. You'll find it has a little plastic one-way valve that hangs loose in the breather hole.

If you can't find it let me know & I'll post a picture.
 

Dave Bilyk

Dave Bilyk
Supporter
Thanks guys,
latest is; I took the seal to the local gearbox repair specialist, he said it looked like new and was unlikely to leak unless the drive hub was worn (it isnt). He also said that he had seen sealant used in the centre of the roll pins and since the roll pin was broken that was the more likely source of the leak.

Which brings me to the more important issue, of why the roll pin broke. I note that it is actually broken in 3 pieces, the third one had fallen out already. The pin has broken at both interfaces of the shaft / drive hub.
On reassembly, I noted that on full droop, the holes in the shaft and hub are about 3mm out of line. So with the pin in, the suspension droop is limited by the drive shaft, and the roll pin carries the full force.
Clearly I need to fix this, the easiest option is to turn the rose joints out another 4mm I will still have enough thread engagement.
So the lesson here is to make sure that there is freedom of movement in the drive shaft over the full suspension travel.
regards
Dave
 
I was told when I got my gear box you should put sealer on the output shaft splines to prevent oil seepage thru them.Hope this helps.
 
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