Jag IRS, Dana Unit Questions?

[Spitfire 350]

I use synthetic 75w90 and limited slip additive in my 44. Amsoil or Royal Purple are both good in my opinion.

[MGBV8]

For a posi, yes.  I used to use the GM additive.

[BlownMGB-V8]

The oil additive is to protect the posi clutches and yes, it is required, although many axle gear greases already include them, and there is some argument that synthetic gear greases don't need them. Cost should be in the $5-15 range for about a 4oz bottle. Available anywhere, even car dealerships.

Jim

[soi6]

Thats for all the help on this, the supplier of the plates sells additive @ $18 so Ill buy that too.

[ex-tyke]

I should use an oil additive that they sell, is this required

Any wet clutch system has to use a friction modifier so that the plates won't stick together. eg. Wet clutches in motorcycles also have to have a friction modifier - my Yamaha, for instance, uses their formula "Yamalube" oil.
$18....wow, a bottle of Ford XL-3 friction modifier in Canada is about 5 - 6 bucks.

[MGBV8]

Graham is the engineer here, not me.  While posi clutches need to be able to slip when the car is turning, a wet motorcycle clutch is not quite the same. Don't want that clutch to slip when under power.

I have owned motorcycles since 1973.  I have never used a motorcycle oil.  Motorcycle spec oil has only been around 20 years or so.    Wet clutches (motorcycles) do not need special oil.  Just do not use any "Energy Conserving" motor oil that may cause clutch slippage.

I find that Rotella T4 (conventional), T5 (blended), or T6 (fully synthetic), all MA/MA2, rated in 15W40 gets it done for most of my bikes.

[BlownMGB-V8]

It doesn't have to be the high dollar stuff to do the job. Ford has used many trac-lock posi units, their additive is fine.

Jim

[ex-tyke]

....I have owned motorcycles since 1973. I have never used a motorcycle oil.

Standard motor oil has never worked in the any of my Yamahas without the clutch packs sticking together .....maybe that Tennessee snake oil has some secret ingredient.

[kstevusa]

Back in Muscle Car era, the LSD,TracLoc, Sure Grip or Posi required the Special additive to allow the clutches to slip and not try to lock during turning corners.  Ford, GM, Chrysler and AMC had their own  name   for the additive, but all did the same function. Originally; GM used whale oil as their lube. Unsure what others used.  EPA changed that and few other things.
Factory Service bulletins noted:  Add the special oil when customer complained of noisy (popping) rear end when turning.  Once added, you went to parking lot and made circles both directions to mix the lube and lubricate the clutch packs.  Usually problem was solved.  Ford additive came in 4 fl.oz, and smelled BAD!  None of had a pleasant smell.  My story and I'M sticking ti it. :-)

[MGBV8]

Standard motor oil has never worked in the any of my Yamahas without the clutch packs sticking together

Must be that darn cold weather.  Or, you aren't riding hard enough.  

Trail riding, street riding, motox & drag racing, I have never had any issues with motorcycle clutches.

[soi6]

For people living in the states  be greatfull for the cost of parts, the plates & additive has cost me $174.50.....you lot are spoilt!

[88v8]

A bit late as I haven't been following this, but do Hauser supply these parts?
https://www.hauserracing.com/pages/parts They specialise in axle builds.

Do agree about the shipping and import duty, self-inflicted in my case as I chose to run an American car.

Ivor

[soi6]

Yeah i got the parts from them, I must say it was a PITA to get the plates into the carrier, not a job for some one that does not have some ability. But its looking good, & Im pleased with the outcome, thanks every one for your help!

[BlownMGB-V8]

Yeah, one of the down sides of the trac-lock. But they do a fair job once set up... until the plates wear. The first 10K miles will be good though.

Jim

[soi6]

Is that 10k of hard use or moderate use?

[BlownMGB-V8]

I think I'd have to say moderate but YMMV. With the weight of the MG you could get much more out of it. It is however a steadily decreasing effect and at some point the clutches will need replaced. The thing is, wear will occur even if you never spin a tire.

Jim

[88v8]

I'd no idea their life was so short.
And presumably the wear particles find their way into the bearings.

A viscous lsd like the Nissan R200 that can be fitted to the TR6, seems a better idea. Pity they're not more available.

Ivor

[MGBV8]

"And presumably the wear particles find their way into the bearings."

That would mainly just be the clutch friction material.

[BlownMGB-V8]

The wear particles don't seem to be a problem, apparently they are small enough and fall to the bottom or get minced by the gears. Personally I like the Power-Lok instead for a number of reasons. Having all steel clutches, they last longer. Having ramps on the cross pin ends they are less dependent on the cup springs to apply, they are easier to assemble, and have twice the number of spider gears. But they do wear also, just not as fast. They can also be heavily preloaded if desired. Of the entire spectrum of less expensive posi units they are probably the best, although some drivers would prefer the Detroit Locker. Moving up in price of course you have your gear type, viscous, and of course on-demand electric or air lockers. The gear type were once considered THE thing but that was before everyone realized that they can't ever transfer 100% torque to the driving wheel. Every design has limitations, you just have to pick the ones you can live with and afford. I'm not sure exactly what the limitations of the viscous ones are, not having driven one, but I suspect heat, and less that 100% load transfer.

Jim

[soi6]

Now having rebuilt this, I can see its not such a big deal to leave the axle in the car & pop out the carrier to replace the plates when its time.

This Dana diff has a 2.88:1 ratio, I do have a salsbury Power Lock unit with a 3.7:1  ratio in as new condition in my spares stash, maybe use that if this 2.88 is not a good match later on.

[BlownMGB-V8]

May want to look for a set of gears around 3.31, I think that will fit the 3.71 carrier but check. Look for a set of original Dana gears as they are harder and will wear longer.

Jim

[soi6]

Ok I note your comments, Jim is your MG at stock ride height? Im ready to set my diff in the car & see your build. Thanks

[BlownMGB-V8]

Tim, I'm not sure which means probably not. I went to some trouble to be able to make the half-shafts the limiting factor rather than the upright bells and to preserve maximum suspension travel. It probably sits about at stock height or maybe a little lower but of course it's also 6" wider.

Jim.

[MGBV8]

Shame that the How It Was Done page is so behind on Jim's updates to his car.

[BlownMGB-V8]

There is some info in the 340 thread and the roadmaster thread though.

I could submit an updated HIWD but would it ever get posted?

Jim