okay I've been bothered by the amount of lateral run-out that I measured in the case in those V
blocks and I decided that I wanted to check it further and so to eliminate any problems caused
by the V blocks I put the bearing cups and the adjuster sleeves on these side bearings and put
it put this differential case with the ring gear back into the differential housing now I did not
put in the pinion gear it's right here so this allows the ring gear to spin freely on its side
bearings and I've got a dial indicator hooked up right here and I'm going to measure the run-out
on the back of the ring gear now by measuring the run-out on the back excuse me of the ring
gear we can see what effect the run out of the differential case had on the installation of the
ring gear and so we're at zero right here which is the farthest wobble towards the pass and that
would be towards the, yeah, the passenger side of the vehicle but as I rotate it around notice I
get clearer up to six a little bit below zero six we've got more than double the amount of
recommended run-out this wobble side to side lateral run-out that we should have and that's
a problem because we have to have the pinion gear mesh and have backlash and blacklash means
clearance between one tooth and the next and the problem we've got is the backlash specification
is five to seven thousandths of an inch with six being preferred and if we have a seven thousands
wobble back and forth in the ring gear as it contacts the pinion gear we're going to have
a backlash variation that's most likely going to be more than mm backlash variation that's
allowed on any gear set and if you try to put it together with more than two thousandths of an inch
backlash variation and variation is that you have to measure the backlash on every single
tooth and compare the highest one to the lowest one and if it's more than two thousandths of an
inch difference it's bad and that doesn't mean it won't drive down the road obviously this
was driving down the road before but what it does mean is that for reliability sake
and noise sake and vibrations sake this thing is going to probably make noise and since it would
it would be once per revolution it would match tire speed it would probably be some sort of a
wah wah-wah-wah-wah type of noise coming out of here we would have to set the backlash really
loose in order to not bind any of the gears when it's when they're at their tightest point so this
is a real concern and if this was a more modern vehicle I would recommend to the owner that you
try to find an another differential case but I'm going I still need to talk to the owner and said
he wants see what he wants to do but I imagine differential cases for 63 Chevrolet Biscaynes are
hard to come by especially ones in good shape but I may be wrong I don't know but this is a
problem that is bringing this reassembly to a halt until I can discuss with the owner what options
there are and what he would like to do so this has been a demonstration of measuring the lateral
run out on the back of the ring gear during the process of installation you can also do this on
disassembly and you should do it on disassembly just to see where it's at especially if you're
going to reuse the ring gear and then as you may be able to see right here there's a missing ring
gear bolt there's two missing ring gear bolts because as we discussed yesterday two of the
bolts stretched and that brings this project to a halt also until we can get some replacement bolts