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Differential identification

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JoeOtero Avatar
JoeOtero Joe Otero
Lexington, Kentucky, USA   USA
1963 Triumph TR3B
1968 Triumph GT6 MkI "Cali"
1972 TVR Vixen
Greetings follow forum members..

I'd like find more information about the differentials I have.. One is a spare that came with my car (has number stamped top side). The differential which is currently part of the running gear does not... It does however have a number off to the left side.. (see pics below.)

I've searched the site and the internet and have not found any information.. Any help would be appreciated..


Cheers
Joe Otero

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charleyf Silver Member Charley Fitch
Redding, California, USA   USA
1962 Triumph TR4
1963 Triumph TR4 "MR.T"
Joe,
The first photo is of a TR3 rear axle likely a 1960. Rear axle numbers were not recorded with the car but seem to closely correspond with the commission number of the cars. The second photo is a part number. The other thing to check about your rear axle is the gear ratio that is within the axle. I do not believe there is any external numbering for what lies within. However, I have heard that there was originally a dab of color paint that coded the ratio. The axle could be a 3.7 to 1 ratio which is the most common or could be a 4.1 to 1.
Charley

TR3driver Randall Y
Confusion, Los Angeles, USA   USA
Of course, even if you find the dab of paint, it doesn't prove someone hasn't changed the gears. When TS13571L came to me, it had 4.1 gears installed (and no overdrive).
The 3.45 gears from some of the PI cars will also fit in the TR3 axle (which is what I eventually plan to use).



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

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JoeOtero Avatar
JoeOtero Joe Otero
Lexington, Kentucky, USA   USA
1963 Triumph TR3B
1968 Triumph GT6 MkI "Cali"
1972 TVR Vixen
could it be some differentials didn't have a serial number stamped? I did find another number on the right side facing the back plate..

I found a post by Randall back in 2013
"the easiest approach is to lock one wheel (pile something against it) and count how many times the drive shaft turns for exactly 10 turns of the other wheel. The differential action will double the ratio, so if you get 18.5 turns at the driveshaft, it is a 3.7; 20.5 turns means it is a 4.1."

And at first it was like patting my head and rubbing my stomach at the same time... LOL... So, I recruited my wife to help.. she counted 18.5 revolutions when I stopped at 10revolutions with the wheel... So, its a standard differential... but why no stamp.. oh well.. I'll have to check the spare too at some point..

Thanks for the input Charlie and Randall!

Cheers
Joe Otero



Edited 1 time(s). Last edit at 2017-01-02 04:30 PM by JoeOtero.


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TR3driver Randall Y
Confusion, Los Angeles, USA   USA
In reply to # 1424253 by JoeOtero could it be some differentials didn't have a serial number stamped?
I've seen several that have no sign of a serial number. Some gearboxes too. My conclusion is that they just weren't too careful about stamping them.



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

JoeOtero Avatar
JoeOtero Joe Otero
Lexington, Kentucky, USA   USA
1963 Triumph TR3B
1968 Triumph GT6 MkI "Cali"
1972 TVR Vixen
Well, still waiting for my tub and chassis to be done (sent to metal cleaner)... I started cleaning the differential today... As stated earlier in this post there was no serial number... Well, that is until I started cleaning it.. See attached pic.. seems this differential was stamped on the housing not the top ridge as expected.. appears to be TS82573... I'm trying to find out if this is period correct for a TR3B...

Anybody have any thoughts?


Cheers
Joe O


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TR3driver Randall Y
Confusion, Los Angeles, USA   USA
I'm no expert on TR3B, but that's sure darn close. I believe axle serial numbers more or less followed commission numbers, and the last TR3A was TS83572 in Oct 61.

Plus, I know there was a gap of roughly 2000 in TR3A commission and engine numbers before TS50,000; not sure if they put that gap into axle numbers or not. If they didn't put a gap in rear axle numbers (and didn't restart for TR3cool smiley, you might even have the original axle!



Randall
56 TR3 TS13571L daily driver
71 Stag LE1473L awaiting engine rebuild
7? Stag awaiting gearbox rebuild

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JoeOtero Avatar
JoeOtero Joe Otero
Lexington, Kentucky, USA   USA
1963 Triumph TR3B
1968 Triumph GT6 MkI "Cali"
1972 TVR Vixen
In reply to # 1491982 by TR3driver I'm no expert on TR3B, but that's sure darn close. I believe axle serial numbers more or less followed commission numbers, and the last TR3A was TS83572 in Oct 61.

Plus, I know there was a gap of roughly 2000 in TR3A commission and engine numbers before TS50,000; not sure if they put that gap into axle numbers or not. If they didn't put a gap in rear axle numbers (and didn't restart for TR3cool smiley, you might even have the original axle!


Thanks Randall.. Much appreciated. I'm pretty sure that its a 2 in the fourth position of the serial number... Not real easy to see it... That would make it 999 earlier than the last TR3A I guess... Does that make sense for a TR3B?


Cheers
Joe O

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