Open Rear Question

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71DartGuy

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This past weekend one of my friends told me about an old trick he used to use on an open rear to help it grip a little tighter. He told me that he used to pull out the spider gears and put extra spacers between the gears and the case. He said it would make it harder for the gears to turn and in turn make it grip a little tighter. I hope I explained this well enough. Has anyone ever done this to an 8.75? I have it out of the housing and figured if it works I may do it while its on the bench. It may be a while til I can afford a sure grip with some steeper gears.
 
Putting extra side gear washers in a 9" Ford was pretty common "poor mans" limited slip. They were put in the side gears and not the spiders. The problem with this set-up is it is very unreliable, you never know when both tires will spin or one will spin.


Chuck
 
Thanks Chuck. I see what your saying about the side gears, that makes more sense. Is it more of a pain in the *** than its worth? I've never taken one of those apart before.
 
I have never done it on an 8 3/4 only a Ford 9". Being the washers index on the side gear it was easier to put them there as opposed to stacking them below the spider gear then trying to keep them all lined up as you rotated then into the housing. Basically what is happening is you making the gears not mesh correctly on purpose and putting them in a bind making extra friction.

I would just put it in as is and just save your dough for the sure-grip.


Chuck
 
First off this could work but will wear out faster than a real posi unit.

In time you could see wear on the side thrust surface of the side gears and mating location in the carrier case.

As far as the gears meshing, this method will force the gears together into a full tooth contact condition (or close to it). This condition may be stronger than what a typical clutch type posi unit does, which is force the side gears apart with springs to provide force on the clutch paks. By forcing gears apart the side and spider gears are engaging at the tips and are more likely to break teeth off.

Some people will remove the springs in a clutch (EATON) type posi unit and shim the clutch paks so they are tight enough to preload them selves and the side gears.

This sort of thing is easiest done with a two piece carrier that splits in half and is bolted together. Tightening the bolts at the end is much easier way to apply preload, than trying to force the spider gears in place simultaneously. I heard it works well on ford rear, is basically a pain with a chevy rear and I have not tried it with a MOPAR rear (since I have a few posi units).

Bob
 
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