TR2/3/3A Lockheed Diff...why is it considered 'weak"...

[karls59tr]

in comparison to the Girling unit? How difficult would it be to swap a tr3 diff into a TR2?

 

[TR3driver]

Ultimately just because the earlier axle frequently breaks; while the later one almost never does (under normal driving anyway, the racers still break them).

The later axle uses tapered roller bearings to carry the side load in corners, which are much stronger than the simple ball bearings used in the early axles. The connection between the shaft and hub was changed to a locking taper that locks tighter over time (making them very hard to separate) instead of straight splines that can wear and work loose. And I believe (not certain) that the half shaft is thicker through the important "overhang" area between the bearing and hub.

Haven't done it myself, but from what I hear, the swap is pretty easy. You'll need the complete assembly including brakes (probably best with the smallest slave cylinders); which then just bolts up to the springs, hydraulic line, and handbrake cable.

I'm sure you know this, but for any lurkers who might not : The rear axle assemblies were of course not actually made by Girling or Lockheed; the names refer to the kind of brakes that were installed at the same time. The early cars had Lockheed drum brakes all round; the axle assembly changed at the same time as they changed to Girling brakes with front discs.

 

[CJD]

The Lockheed axle tends to break at the splines, which is bad. The good news, as I am finding out working on it, is that you can change an axle in not much more time than it takes to change a tire. The hubs can be removed by tapping with a wire wheel mallet. The Gerling axle has to be miked for end float during installation, and it takes a 50 ton press to remove a hub...so it's not a roadside procedure.

 

[martx-5]

The Lockheed axle tends to break at the splines, which is bad. The good news, as I am finding out working on it, is that you can change an axle in not much more time than it takes to change a tire. The hubs can be removed by tapping with a wire wheel mallet.

Depends on where the break is. Here's a video of the 50th anniversary of the Jabbeke TR2 speed run. It's about an hour long, but the broken axle starts at 14:15. They had to remove the diff to get the broken piece out, but it was done in the parking lot. So I guess you can call it a roadside repair.

https://www.youtube.com/watch?v=ZVCEvK3JMng