Diff Lock for C15

[John Stokes]

Hello again all,
I am trying to find out if there were compatible diff locks for Chev diffs in CMP'S. 6.5:1 ratio 16 spline axles 1.735" o.d. 1943. John Stokes

[Tony Smith]

John, do you have a copy of the Chev Maintenance Manual MB-C1? There is some interesting info there regarding the C15 differential that might surprise you.

For other 4x4 CMPs there was a locking differential made by Thornton-Welles that was listed in the parts books as "Optional", but I haven't found any reference to which applications of CMP truck required this option, and certainly haven't seen any surviving units of the Thornton-Welles locker.

[gjamo]

Don,t quotem me on this as I haven,t tried it first hand, but I have been told that C15A diffs are Clark or a close copy. If this is the case Detroit lockers are available from a lot of earth moving apps that may fit.
Graeme

[John Stokes]

Originally Posted by Tony Smith

John, do you have a copy of the Chev Maintenance Manual MB-C1? There is some interesting info there regarding the C15 differential that might surprise you.

For other 4x4 CMPs there was a locking differential made by Thornton-Welles that was listed in the parts books as "Optional", but I haven't found any reference to which applications of CMP truck required this option, and certainly haven't seen any surviving units of the Thornton-Welles locker.

No Tony i do not have the maintainance manual ,what will amaze me about the diffs ?

[Tony Smith]

Sorry to leave you hanging in the lurch like that, John, but I had hoped a Chev afficianado might have stepped in here while I was searching for my MB-C1.

The following is an excerpt from the Chev Maint manual. As far as I know, the C15 is the only CMP, MCP or even WW2 2WD to have a traction enhanced differential fitted as standard. The Manual does provide a description and diagram of the unit, but it is not detailed enough to ID the mechanism. While not a Locking Diff as such, it appears to be a type of LSD, but of which type I don't know. Early LSDs were produced by Eaton as Posi-Locks, and Gov-Locks for smaller applications, but the CMP diff is in a sort of in-between zone between light-duty car diffs and heavy-duty truck/earthmoving diffs, and I don't know what applications were provided for in the early LSDs. It would have to rate as one of the earliest production installations of an LSD in a road-oriented vehicle.

[Lynn Eades]

The last paragraph inplies a Borg Warner type lsd,(as fitted to 70's and 80's Holdens and Falcons) where the side gears, under load, act to lock the side gear to the carrier.The side gear is angled at the back, and wedges into a matching taper in the housing.
Incidentally the Detroit Locker was fitted in the 6x6 Dodge T223 during ww2, and as I understand would still drive one side, when the half shaft on the other side was broken.