Diff. removal and jackstand placement -Snapped output shaft

[SubaruPaul]

Update:
Unit is going to be fine. Axles removed , internals inspected , not much to do but replace the diff. gasket and axle seals. Yes - it was a clean break on that driver's side axle.

Note - we were all curious as to why there is such a bind when rotating the input from the prop. shaft flange. That's supposed to be there at around 7 lbs. of pressure before it breaks loose.

Can someone explain that for me? Is that because these are posi-drive? Or ??? - please educate me. Thanks!

I also noticed that these are typically a 3.9 unless optional gearing was ordered. Same as our old Subarus - 3.90 that is. Datsun guys use our LSD units at the drag strip. FYI

[billwill]

A standard Lotus diff was 3.77 as fa as I know.

I never heard of a 3.9 in this context. Try counting the teeth again ?

[paddy]

The 3.9 ratio was standard on the early cars. Robinshaw and Ross says it was on all S1, S2 and very early S3.

Paddy

[oldelanman]

Note - we were all curious as to why there is such a bind when rotating the input from the prop. shaft flange. That's supposed to be there at around 7 lbs. of pressure before it breaks loose.

Can someone explain that for me? Is that because these are posi-drive? Or ??? - please educate me. Thanks!

There should not be a high resistance when you rotate the input flange, if there is it's likely that either the differential bearing adjusters have been overtightened when the diff was built or, more likely, the pinion bearing pre-load has been set too high. There is a collapsable spacer between the two pinion bearings which is supposed to give the correct pre-load on the bearings when the pinion nut is torqued to the specified figure (30-35lb ft). If that nut has been overtorqued or retorqued without replacing the collapsable spacer then the pinion bearings will be overloaded and cause increased resistance to rotation. The pinion pre-load should be 9-11 lb in but you need to add the diff running torque to that when you measure with the diff assembled. If you are worried that you may have a problem you could slacken the pinion nut to relieve the pinion bearing load and see if the flange is still stiff to rotate - if it is it's likely that the diff bearings are too tight. If it's OK then it was the pinion pre-load set too high.

Edit: Should have mentioned you will of course have to reset the pinion pre-load if you do slacken off the pinion nut.

Regards,

[billwill]

The 3.9 ratio was standard on the early cars. Robinshaw and Ross says it was on all S1, S2 and very early S3.

Paddy

We live & learn something new every day on this forum.

[SubaruPaul]

Thanks again! Roger , all great info which I shall pass along. As I know it , Tony the mechanic working on the diff. says the factory manual tells him 7 lbs. ( I'm guessing a +/- in there) on that resistance at the input.

Tony says the unit looked remarkably fit and nothing else it needed internally. Diff. gasket , seals .... new axles.

Bill - my info was from that page posted online witht he exploded view of the diff. I think Chris said his is an S3. For sure its a '67 and one fun car to drive. Lucky me helping with the Remove and Replace action - gets me some time behind the wheel.

As I've heard from the Man , new axles (CV type) have been ordered. One of us will be taking the inner ends apart from the axles and inserting them into the diff. for ease of axle installation. That's the advice we've been given. Also getting urethane bits to replace all those 44 year old rubbers. Rear end of this car is going to be tight. Power to the Pavement !!

[SubaruPaul]

Some pics. Rear cover was bead blasted , cleaned up real pretty - yummilicious!!!


"the Snapper" notice that crescent of initial wound. Worked itself right around. Good thing it was a crescent and not full moon - owwwwooooooo!!!!!


I know most of you don't need to see these but man they make me drool and I don't even own a Lotus. Gotta think these are going to last the life of the car and then some. But then again Chris the owner is going to let me drive it so .....


Is this what they mean by "open diff." ???


Gear tooth wear is exceptional. Indicator showed correct backlash. Really a nice unit for its age.



You guys would flip out if you got to see the pictures and hear the stories Chris and I got to hear from the man working on this unit. Some other time....

[Galwaylotus]

I guess you're keeping the photos for yourself!

[elansprint71]

Let us know when you get on to the front diff...

[paddy]

Let us know when you get on to the front diff...

Not all cars had them, so they're quite hard to find nowadays. Also, the ratios were different from the rear diff

Paddy

[SubaruPaul]

Your board must have not liked them being hosted on a Subaru board. Sorry about that.

FYI - all pics shows up when I previewed the post. I'll be kind at this time for the sake of my friend. How about center diff. ?

[SubaruPaul]

[SubaruPaul]

[SubaruPaul]

[SubaruPaul]