In a message dated 7/9/00 5:55:10 PM Pacific Daylight Time, CLLLSLS@aol.com
writes:
> Hey everybody,
>
> Swapping out the TH350 and 3.08 10 bolt in my '79 Silverado for a 700R4
and
> 3.73 gov-loc 12 bolt. I'm sick of "one tire fires" and no snot off the
line.
>
>
> The 3.73 unit I have came from a 76 chev 1/2 ton. One carrier bearing and
> one
> axle bearing were shot so I've gotten all new axle and carrier bearings
and
> axle seals. I'm thinking I should pull the pinion out and check the
bearings
>
> and atleast replace the pinion seal seeing as how I've got it down this
far.
>
> The Haynes shop manual I have does not give very detailed info at all
about
> rebuilding rearends. I've never actually personally had a rear down this
far
>
> and neither have any of my shop groupies I rely upon for advice. I do
gather,
>
> however, that messing with the pinion nut is a delicate procedure, not to
be
>
> taken carelessly.
>
> Can any of you tell me how I should go about removing and reinstalling the
> pinion and also, I've always understood that shims are necessarry for
proper
>
> gear alignment. I've seen guys set up rearends before, I understand the
> principles, I even have some prussian blue from who knows where, but I've
> never done it myself.
>
> I didn't pull any shims out of this rear when I tore it down. just two big
> thick precision washers(one is ruined from the bearing spinning on it). Is
> there some sorta "shim kit" I need to get to put this thing back together
> right?
>
> Please help! Thanks,
>
> Dustin
> '79 Chev 1/2 ton short wide
> 50 & 53 GMC 1/2 tons
> 48 GMC 3/4 ton
> 48 GMC 1 ton
Dustin,
I've set up a few rearends, I'm suprised you haven't found any shims, but
I've not done a "gov-loc"...least I don't think I have....did you look
between the carrier bearing and the carrier? Also, when you pull the pinion,
they may be under the race in the housing as well.
Best thing would be to get the GM shop manual or a MoToRs that covers your
year model, the exploded views are priceless.
To remover th pinion, you'll first have tpo remove the carrier..remove the
pinion nut, and then pull the pinion gear out from where the carrier side is.
If you notice shims behind any press fit races....take the old race and
file it some so it will slide in and out of the housing, or the inside of the
bearing so it will slide off and on the carrier or pinion (where ever a shim
would be behind a press fit) to use as a "test" fixture"....quality bearings
(Timken, BCA, etc) are all cut to within .001 of each other and the races
rarely wear unless the bearings were run dry
Set up the pattern starting with the old shim stacks first, then once it's
right, put all the new bearings and races in, and recheck the final
patterns....do you have a crush sleeve on the pinion? If so, talk to a rear
end shop and ask about a spacer for a crush sleeve eliminator, then you'll be
able to set the pinion pre-load via shims, and not worry about the crush
sleeve losing it's "crush" over time.
Use a non-locking nut for the initial pinion setups and get a NEW pinion
lock nut for the final assembly.
Since you're able to read the contact pattern, the only "special tools"
you'll really need are a 0-40 in/lb torque wrench and a mounted dial
indicator to check backlash with...once you get the feel of the backlash
setting and the correct pinion pre-load, you probably not even use them again
until the final check.
If you're really unsure of the pinion depth and can't make sense of the
contact pattern, give me a holler, I found a website (that I have saved
somewhere) that sells "unviversal pinion depth gauges) for $99.99 plus
shipping, pretty good deal.
Mike
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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