Engine and Transmission Tech

Im going to use this Jag XJS powerlock diff in my MGB Sebring, the diff is in good shape other than one of the LSD plates is shot.
I only need one plate, what other axles are these in?, I dont really want to buy a complete set as its rather a lot of money. One other thing, are the Jag IRS Dana & Salisbury units fitted with the same size bearings? thanks

Tim, the bearings have different taper angles iirc. A wide range of applications used the power-lok but people confuse it with that other posi.

Jim

If this is Dana 44, use their plates, as-in ebay/etc. ?

Do you have dimensions of the plates?

I rebuilt a SD1 Salisbury LSD using plates from a Dana locker. Actually, I bought a complete NOS locker for less than I could buy the plates!

I still have my old plates and can compare. The Salisbury posi was heavily designed on the Dana - the spider gears are identical enough that they work, and the cross-shafts are longer on the Dana, so can easily be cut down to suit the Salisbury.

Most of the salisbury and dana parts interchange except for the bearings and the side gears. Spline is different on the side gears. Bearings can be mixed and matched to work so that dana parts can be used in the salisbury. Ring bolt size varies but there are bushings available also.

Jim

Thanks for the replys, Ive finally have the unit apart.

Turbodave, I have the sizes now, the plates with the two ears, 86.19mm x 57.76mm,

The plates with the teeth are 84.79 x 51.39mm they have 42 teeth. this was measured with a cheap ebay dgital vernier caliper.

I'll check my plates tonight and will get back with you. First thing that's definitely different is that the SD1 and Dana PowrLok that is of a similar size has four lugs on the plates.
This is a pic I had on my phone of the Dana vs the Salsbury components. You can see the four-lug plates. The plates has the same curvature and thickness, splines, and dia - the only difference was the DANA had squared lugs, the Salsbury was rounded.

There are other, fairly minor differences. For instance you may find the side gears on one have a shoulder which gives it a longer spline and the other doesn't. Most of the parts are interchangeable though. I have not seen the clutches with the rounded tabs I don't think.

I have mixed and matched some parts but try to stay consistent within the carrier if I can. You can set the clutches with up to 120 ft lbs of torque loading which is a little high for an MGB but does work OK. Makes it hard to push by hand in the shop though.

Jim

This is two of the plates from my diff, over here in the Uk I can only find Dana 44 plates listed for jeeps. And they are about twice the price that you pay, so I would want to buy a set from the US & get them sent over, just dont want to get it wrong...

Jim, do you think these will work? thanks


[www.ebay.com]

One other thing, one of the retaining clips had come out & was in a bad shape, can you get upgraded, stronger clips? or is there anything to help keep them in check? thanks

Those look to me like the right parts. Your old ones don't look too badly worn, what is the most important thing is when you put it together, rig an axle shaft or stub shaft so you can put a torque wrench on it, and see what it takes to turn the side gear. If you are in the 60-120 range it should work just fine. The difference is in the thickness of the stack. I think Jag sets theirs up for 80.

Now that I think about it, the rounded ears and clips are familiar. Don't really remember where I've seen the square tabs but I have seen them somewhere. I think both the Power-Lok and Trac-Lock use the rounded tabs but the Trac-Lock uses fiber friction surfaces. As for the clips, those should be available individually. The clutch plates should as well. Plus if you check with any local axle shop or Jag shop or dealership they should have surplus parts lying around. Dodge also if they work on the old stuff. As much as I appreciate the attraction of new parts this is one place where used parts can sometimes let you dial in the performance you are looking for. Being a light and narrow car, the MG doesn't need the full 120 ft/lbs. I haven't noticed it hurting the cornering, but then I threw out my baseline when I also fitted a different front bar so I can't really say for sure.

Jim

Thats very helpfull thanks, I hope this Jag IRS is worth the bother over a live axle.

It is definitely going to give you a better ride. I don't think you will notice much difference in the cornering characteristics but the tires will stay planted better on uneven surfaces and that will help. The most noticeable difference is going to be the absence of the jolt in the back the stock axle gives you over highway expansion joints. Just that alone can be reason enough.

Jim

Yes good, my only reservation is that Im building this car with a rear mount turbo, and room for the pipes could be a little tricky, but Ive some ideas how Ill go with this et up.

Well having asked on about 5 forums still nothing, I dont fancy chancing sending for a set from the states & finding them to be incorrect not at $150 a time, so Im thinking about welding the plate with a broken ear to a good plate. Not very good but not much else I can do.

You should learn to do a google search.

[truckandgear.com]

[cppdiesel.com]

Google: Dana 44 power-lok clutch

Jim

Thanks for that, but Ive found many sets on the net, some look identical & some are not, Ive yet to find a set listed for my application.
My problem is, Im in the UK the shipping & import duty makes that US price about double, bad enough if the parts are correct, but very bad if their wrong.....I dont feel at this time I want to chance it.

So you don't think the Dana clutches will fit the Jag Power-Lok? Odd, I've found them to be interchangeable myself.

Jim

I have a Dana 44 trac Lok in my Jag Diff, they were fitted to XJS for 3- 4 years back in the eighties, these dana LSD plates come with a different tooth count on the internal bore, & some have 4 lugs whilst mine has two lugs.Is the diameter the same on all? I dont know, Ive found some that have the same ID tooth count & the same two lug plates, but Ive asked sellers for ID's & OD's but no one has answered me on that.