[TR] Replacing or rebuilding TR3A differential

Dave MacKay dave at mdmackay.ca
Thu Jul 2 10:24:00 MDT 2020


The pinion gear in the 3.7:1 differential of my 1960 TR3A (s/n 68639L) broke
a couple of teeth so that now I need to rebuild the differential and replace
the crown and pinion gears. I’m intimidated by the repair because it looks
like the repair requires more expertise that I have and because the TR3
service manual specifies special Churchill tools that I don’t have and that
seem to be unavailable.

The idea of replacing the differential rather than rebuilding it holds
considerable appeal. I’d welcome any suggestions from the list about
- Where I might be able to source a working diff to replace mine with?
- Any readily-available rear ends that I might be able to swap in (e.g.,
from another model or make of car)?

If a replacement isn’t feasible, I’d appreciate input from the list about:
- Shops/mechanics that have experience rebuilding Triumph differentials
- Where I could buy/rent/borrow the special Churchill tools that the service
manual specifies
- Alternatives to the Churchill tools (S101, M84, S4221, S103, M70, TS1,
M85, S132/2)
- Advice about other tools that will be needed (e.g., what size press) or
outside services that would make the job easier

Of course any tales from those that have been there/done that would also be
welcome.

Thank-you,

Dave MacKay
1960 Triumph TR3A, s/n 68639L
near Toronto, Canada


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