[Fot] Broken Diffs

[Chip Collingwood]

Hey Bob,

And happy Thanksgiving. When I was running Fletcher's old car I ran a diff
cooler to help with failures. At the time it was set up with a belt on the
right side stub axle and mechanical pump. If I did it today I would use an
electric pump.
I also burned through a couple rears before I properly matched my
revs...too much pressure on the diff...using it to slow the car instead of
my brakes.
I think I turned some of my fastest times 1:25 at Summit Point but
sacrificed a diff going down the shoot with poor rev matching. I may still
have that pinion with no teeth left around somewhere to remind me.
I really think a cooler would help longevity if you don't currently run
one...and yes any form of LSD, especially a torsen/quafe creates a ton more
heat to try to dissipate...even more fluid capacity is good.

Cheers

On Wed, Nov 21, 2018, 10:19 AM Jack Wheeler via Fot <fot at autox.team.net
wrote:

> Should be a lot of used carriers around?
>
> On Tuesday, November 20, 2018, 11:34:42 PM EST, Robert Lang via Fot <
> fot at autox.team.net> wrote:
>
>
> Hi,
>
> I broke a diff at Thompson back in October and I finally did a
> post-mortem. Looks like a couple of bolts backed out and when the shit hit
> the fan, the 4 or 5 that were still holding on sheared off. In any case,
> lots of metal bits in there. Some of the big pieces bounced around in the
> diff and there's some gouges in the Tran-X center section. The question to
> the group is - assuming that I find no cracks in the center section, it it
> accepted practice to clean off the dings to prevent stress risers and
> re-use it or is this a "tosser".
>
> Speaking of Tran-X, does anyone sell those now or are we limited to Quaife
> and GKN? I see that Rimmer lists both of those units. To be honest, I'm not
> a fan of Quaife because I have to run the rear a lot softer to prevent
> wheel spin in the tight stuff - that kills my times at places like Thompson
> and Palmer (like 1.5 to 2 seconds a lap.) Speaking of GKN, I know nothing
> about them other than "clutch type differential". Feel free to chime in if
> you have experience with those units.
>
> Also, I am nearly 100% certain that I was using new lock washers and Red
> Loctite high strength thread compound, so the bolts backing out was a total
> surprise when I cracked the case open. I was assuming that the pinion head
> had sheared off based on how the car felt when the diff broke. It was BANG
> and done - box full of neutrals.
>
> Off topic - looks like I'm not driving at ButtonWillow, I got a reply from
> Joe Siam that he has nothing available for that date. Oh well. Look like my
> budget is going to gears and stuff anyway... ;-)
>
> c ya,
> Bob Lang
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