Information about revised differentials

[131DHOC]

Hello, as you may know I have yet opened a topic about differentials, as I broke my 1367 twin cam differential. Now, as far as I can see, soucing this part may be difficult. So I opened a new thread to ask: could it be possible to revise the existing differential? Do you know how to find a place that does this stuff? Using the net, I could't find any garage specialized in revising differentials in my town. I have no experience apart my local mechanic, so I'm a bit lost. As my car is a low powered one, it may be possible to repair the old part, as it could be just a matter of bearings and adjusting, not of broken gearwheels. Any suggestion from people with more knoweledge and experience than me could be useful, the car goes well and it woud be a pity to scrap it for just a differential.... thank you.

[miro-1980]

Take few pictures and show us what parts /elements of the diff is broken.

I may have some spares ...

The gears of the diff are not repairable and  need to be replaced AS A SET !!!

The bearings are easily to source.

Will try to help you ...

Miro   

[131DHOC]

Thank you a lot, my mechanic says he has no time nor tools to assembly a differential, it's been lot of years from the last time he did such a thing, I know the gears must be a set, they are paired and carry a sheet with data because of micrometrical precision of the system. I asked two sellers on ebay that are supposed to have some ancient differentials but there's nothing sure. Can you please tell me where should I search for the item number on my old differential? It's still on the car and I can't disassemble it but my mechanic could set the car on the elevator and I could take a picture after removing tar and grease.... thank you.

[jasonh131]

Theo . Did some swoping off gears on his 131 a bit of trial n error to get the backlash right al in situ...

[131DHOC]

Well, finally I had the car repaired, the problem was the broken pinion, had one teeth broken and other ready to follow. I found an used unit, complete and with low wear. Got all the bearings, spacers and seals new, and my mechanic which some years ago assembled differentials for a local fiat dealer did the work. Run 25 kms this afternoon and no noise, no vibrations, nothing. These are the old and new parts....

Broken pinion:


Old differential with loose planetaries:


The "new" one:



Very hard to find 9/40 gear ratio:



Have no pictures of the replacement differential, but it was exactly the same as the old one.
Edit: I found some pictures from the seller:





Tomorrow I'll go more kms and see if it was worth the time and money spent to find this used part. You can get dozens of 10/41 and 12/43 brand new and at very good price but this 9/40 one seems to be very elusive....