Howdy y'all.

I bought a cross pin diff from Minispares in the UK. When my mechanic fitted it up to the side gears, he was worried that it all felt pretty notchy. I emailed Minispares. They said they'd had a few with this problem, so they sent out some new planet wheels (8 weeks later). When my mechanic fitted them up today, he said it was a bit better, but still not very smooth.

I've emailed my contact at Minispares. His reply read:

"Hi Matt, we’ve given a few of these diffs to our gearbox builder which were almost impossible to turn by hand and all of them were perfect after running them in a small distance, I don’t think a new diff would be any better so I would suggest you try that diff first on the road (it should free up almost instantly).

Kind Regards

Gavin King
Purchasing / Technical Adviser"

What do you all reckon? Should I chance it with this diff or try to get my money back and get something else? I don't want to end up with bits of diff swimming in the oil in my freshly built engine. This is the last thing that has to be done before the engine goes back in the car.

All advice welcomed.

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Cheers, Matt

Don't be fooled, Gruhms is not my real name.

Minispares used to use genuine Rover planet/spider gears in these diffs, but they are NLA now I think.
Maybe their current gears are not as well made as previously...?

Another cause of notchiness and stiffness is side gear thrust washers that are now too thick. This pushes the side gears into the planet gears.
On recent standard diffs I've rebuilt, I had to shorten the centre spacer by .005-.008" to allow for this thckness change.. It is a PITA how manufacturers change material thickness on this sort of stuff.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

As the Doc says, check the output shaft thrust washers. The early ones are 0.035" and the late ones are 0.048".

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The best thrust washers were the flat bronze ones, used in 3 synchro boxes. If ya dismantle any, grab these washers.
Unlike the fibre ones, they don't die and break up after long periods in dirty Mini oil/sludge.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Thanks fellas. I think we're just going to take a bit off the thrust washers and go with it. I'd like to have some kind of guarantee it's not going to stuff my engine, but that's not how the mini game works.

I'll just have to drive with my fingers crossed.

_________________
Cheers, Matt

Don't be fooled, Gruhms is not my real name.