UN1 gear box repairs

Hi ,I am repairing my GTA gerbox , I am installing a Quaife diff and changing the diff ratio due to big wheels . The diff i am using is out of a R25 UN1-03 but my problem occured when I found that the secondry shaft was worn at the pinion end underneath the large bearing. As the bearing runs directly on the shaft ( no inner part to bearing) the shaft is irrepairable.But if I use the bearing out of a UN5 (Renault Master 89-98)
It has an inner ring ,so I can grind the shaft and fit the new bearing.
Problem is that it is not a standard bearing and I might have to get it from Renault, so what I actualy need is the Renault Part number or a Vin number for a 89-98 Renault Master .

What ratio is the diff changing from and to?

I was wondering about a change too.

[stephendell]

Diff changing 3.44 to 3.89

Have you got a copy of the UN1 repair manual? if not there is a copy in the technical help section.
Go to the last couple of pages which shows a gear/ shaft breakdown with postion numbers. Let me know the number of the bearing & I will see whats what.

The UN1 manual states the 3rd and 4th gear are not removable off the secondary shaft but I have spoken to several people who have. the UN1 bearing is an SNR NU 10705 but I need to replace it with the bearing from the UN5 gearbox providing that no other diameters along the UN1 box are greater than dia 38mm ?

Hi,try Mark@Bearingkits.co.uk 01279793631,they may be able to help.

In the pictures are the only bearings available separately from a UN5,
If you can post the actual dimensions we could check our UK suppliers?

In the pictures are the only bearings available separately from a UN5,
If you can post the actual dimensions we could check our UK suppliers?

http://i200.photobucket.com/albums/aa171/red21t/UN5gear1.jpg

http://i200.photobucket.com/albums/aa171/red21t/UN5gear2.jpg

http://i200.photobucket.com/albums/aa171/red21t/UN5geardiff.jpg

The bearing is dia 80mm od 24mm wide with no inner ring , an external retaining ring and the rollers run on the secondary shaft which is about 42.65mm dia. The UN5 i think is the same but it has an inner ring with an id of 38mm.

At present can't help to much, but you can try this SNR web page
https://www.ntn-snr.com/catalogue/fr/en ... ue/home/ra

Been there