<VV> Rebuilt PG installation

Brent Covey brentcovey at hotmail.com
Mon Jan 30 19:38:42 EST 2006


Hi Graham

> mentions the need to determine the required thickness of spacers for the
rear selective
> thrust washer at the govenor gear location when reattaching PG to
differential. Any other
> way to verify the required clearance; or do I even need to worry about
this?

If the units out of the car, its pretty easy to set up.

IIRC the correct clearance is 0.020"-0.035" range. I think 0.025" is about
where I shoot for, basically anywhere in the lower 1/3 of the clearance spec
is pretty good.

What you're looking for is to give the stubby internally splined shaft a
little room to float backward out the back of the transmission before it
bashes up against the governor gear, but not too much. you will want to err
towards the tight end of the clearances the factory suggests for the
quietest transmission operation.

Usually most cars came with two shims, ones about 0.015" and ones about
0.28"- you can measure them with a pair of calipers or compare them to
feeler guages to find which size you already have on hand. Most cars will
work with that stack OK and still be within proper clearance.

To measure the actual clearance you have, stand the Powerglide nose down on
the flat oil pump face with the pump shaft standing up. Place a used gasket
on the back of the case. Next, make a small ball of putty or clay and after
seating the governor gear fully on the splines of the pinion shaft, place it
on the gear facing the transmission (forwards as installed in the car) and
have a helper assist you lowering the differential gently onto the upended
Powerglide. Do two trans to axle bolts up securely diagonally oppsed and
then take it apart carefully. The impression in the clay or putty will allow
you to determine the amount of clearance present and how thick a shim stack
will be needed to get it pulled into spec. If your car came with a 0.015"
and a 0.028 for example you might find two 0.028" shims takes up the slack
fine or if you replaced the thrust washers perhaps two of the thin ones are
needed to increase clearance from original. Other shim materials can be used
as long as they'll stay put and not rub anywhere if you need to fine tune
things and dont have extra factory shims availible.

The reason for doing this with the trans on end is that moves the internal
parts to the front to max out clearance for accurate measurement of the
total play. If your diff is still full of oil its a bit messy if you dont
drain most of the oil first. This is a important clearance to get within
range for a good quiet fast shifting long lived transmission, so its worth
checking it out.

Hope thats some help,
Brent Covey


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