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TR2/3/3A Locker Differential- I have one but what is it?

71TR6

Jedi Hopeful
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Earlier today I opened up my differential and was surprised to see a locker in it. The previous owner hill-climbed it back in the 70s so that makes sense and also explains the 4.55:1 ratio I noticed I have.

IMG_1106.jpg

My question to the forum is: The only marking I was able to find on this is #63924. Does anyone know what make this locker is and where I might find some information on it?

Thanks again!
 

CJD

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It looks like a solid axle to me. In other words, it's not a differential at all. Have you been driving it on the street? If so I bet it binds and skids on slow turns...real bear in the parking lot?
 

TomMull

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Since you called it a "locker" it would seem that you've got a pretty good idea of what it is. Not quite a solid axle but not a clutched limited slip either. If it is a "locker" as it appears to be, it is a limited slip with some sort of a ratcheting system. I'm told they are a bit quirky to drive but it won't scrub the tires in the parking lot. I'd at least try it out if I were you. Perhaps one of the racers will chime in.

Tom
 
OP
71TR6

71TR6

Jedi Hopeful
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It is not a welded differential that drives both half shafts at the same time since the unit is a manufactured addition. When I turned one wheel while the other was held rigid, it clicked and locked so that function, combined with the previous owner's comment that he competed in hill climbs in the 70's, lead me to assume it is a locker. Maybe I made a wrong assumption?

The car was parked in a barn in 1978 and was not drivable when I bought it in 2015 so I have no idea on any quirky handling characteristics that might exist due to the locker. From what I've read about these, the understeer when accelerating can cause a little anxiety under the right conditions. Regrettably, the previous owner passed away a couple of years ago so I'm not able to get more details on the car or the handling.

As you mention Tom, I'm hoping one of the racers can chime in on this to provide some insight. I'm just looking for some information confirming what this thing is, who made it, and is it worth keeping installed in the differential.

Thanks,
Ron
 
OP
71TR6

71TR6

Jedi Hopeful
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Yup Tom, that sure looks familiar.

I did a search on the part number I found and was surprised to see one listed on Ebay. The seller posted a disassembled image of the unit that confirms it is a locker design but it doesn't appear to have the pin-style carrier used on modern Eaton units. https://www.ebay.com/itm/Triumph-De...tin-Hillman-Rear-End-63924-63923/233717259163

I also came across some references that Bill Dentinger raced a locker in his 56 Tr3 with a 4.55:1 ratio rear so that further adds credence to what I have is set up for racing. So this now begs the question whether this differential is streetable with my overdrive transmission or is it strictly appropriate for track use?

Ron W
 

mixdenny

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In the late 1960s I had a Speedwell locker from England that looked like that. They were licensed by Detroit Locker. It worked very well. No problems on the street as the the inner axle can under run. The only quirk I ever noticed was an occasional slight bang as the unit locked or unlocked from a stop. Did it once at a turnpike toll booth and scared the toll booth guy!
 

Rod-H

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I checked out the one on ebay and its innards looks to function very similar to how the Powertrax units do. Should do the job quite nicely.

Rod
 
Last edited:
OP
71TR6

71TR6

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Thanks for everyone's posts. I've decided to refurbish another rear axle I have with a conventional 3.7:1 rear end that is a better match to the overdrive transmission I picked up a while ago. I'll probably sell the 4.55:1 with the locker since someone who races can probably make better use of it than I can.

Ron
 

tr6healey

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Thanks for everyone's posts. I've decided to refurbish another rear axle I have with a conventional 3.7:1 rear end that is a better match to the overdrive transmission I picked up a while ago. I'll probably sell the 4.55:1 with the locker since someone who races can probably make better use of it than I can.

Ron

Sent you a PM
 
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