"carier disk"

[mackgoo]

On the latter tansmissions, starting with say 74 on, on one side of the differential they show a "carier disk". Does any one know what it's function is? Is it a glorified spacer? They still call for 2 bearings so it's not a bearing.

[Jim Sims]

In 1976 the installation of a disk with magnets was made on the 915 differential carrier to provide pulses for the pick-up coil of the electronic speedometer; the changing magnetic field due to the magnets going by generated voltage pulses which were counted to compute speed. This may be the carrier disk you are referring to; I believe it is inboard of the tapered roller bearing and spacer. The carrier disk has clearance slots in it to allow the use of a two arm puller to remove the tapered roller bearing. The puller arms have to fit through these two slots and the tips of the arms may need to be modified by grinding or filing to fit and match the very narrow portion of the tapered roller bearing's inner race that protrudes outside of the spacer. One has to pull against the inner race to avoid damaging the tapered roller bearing during removal and re-installation requires one also push against the inner race. Cheers, Jim

[mackgoo]

Sounds like it. I got those bearings off today. Really pretty easy.

[Jim Sims]

If you're swapping in a new differential carrier or new bearings there's a set-up procedure listed in the factory shop manual; it involves measuring clearance at the housing side cover and bearing/ring gear drag using a beam indicating type torque wrench. Apparently, if the clearance/drag values are out of specification range one has to pull the bearings off and install different thickness spacers and recheck clearance and drag. This is in addition to the pinion set-up shimming procedure. See the factory shop manual. I suspect failure to follow these procedures may result in a noisy differential and/or reduced bearing/gear/pinion life. Cheers, Jim

[Jim Sims]

I looked at the shop manual exploded diagram and the magnetic disk appears to be inboard of the tapered roller bearing but outboard of the shim (there is also a washer inboard of the shim). I also note that the correct ring gear backlash is also obtained by varying these shim thicknesses. One could probably improvise the measurement tooling for the shim measurements for the tapered roller bearings' preload and the ring gear set-up. However, it appears rather difficult to "rig up" a measurement of the pinion face to ring gear center without the special tooling or at least a good used differential carrier that could be machined into a piece of substitute tooling. Maybe someone knows an easy way to do this. Cheers, Jim