Other Cars (British & British-Inspired)

Hi,

I'm researching options to switch a series III xj6 to a limited slip differential. From what I understand, all XJSs up to 1996 had LSD and will bolt in. Is this the only option? I've been searching the internet for hours but to no avail...

I read somewhere that you can use Dana 44 gears but have to make bushings for the smaller Jag bolts. Anyone heard of this?

Any constructive comments would be welcome.

PS I'm wondering if there's a "pumpkin" that will bolt in to the suspension. If this requires a different drive shaft, that's fine.



Edited 1 time(s). Last edit at 05/29/2010 03:16PM by dhen.

Darian, Jim Blackwood did a lot of research on the Jag rear for the Roadmaster Project, take a look through his posts in the MG area of the forum [forum.britishv8.org] for some of the information he dug up.

What is it for - they are Stupidly heavy - no point going this route if you only have a light car MGB or TR type (TR Salisbury fine and less than half the weight).

I have both one for my 6 racer (should be fine to high 200bhp's) and one for my Griff racer (no choice and needs it for the Mental power it will have).

We heard that about the Dana gears - but then did more research that the Jag gears are better.



Edited 1 time(s). Last edit at 06/10/2010 01:46PM by jellison.

Darian, are you trying to find a source of gears that will fit your MGA housing? I guess you've found that even the 3.9 gears are a bit low for your turbo and would like a limited slip diff while you are at it. I don't know of anything that will fit, either in gears or complete pumpkins. Since you run wires you're faced with the same dilemma I am on my MGA project. I haven't done it yet, but I've been researching rear axles and am considering installing the center housing from another axle (probably 10 bolt GM in my case) on the tubes of my MGB rear and saving the MG brakes and splined hubs. I'm using the tube type B rear, but the same thing could be done with your axle using something like a Ford 8" housing in the center. Would give you lots of ratio selections as well as limited slip units.

Thanks for the replies.

No, this is for an actual 1984 xj6. I just bought one off of eBay, and unless I got lucky it's an open diff.

To answer your question, Bill, the 4.1 (it's a MkII) behind my turbo engine is perfect. That engine is happiest around 4500-5000 RPM. I wouldn't mind if it was 4.3, though I'm not going to mess with it. If I recall correctly, you're using a V6, so you probably would be better off with a different axle.

Would it be possible to use the center housing from another axle onto my Jag? If it's too expensive I'll just stick with what I have, but I'm curious.

Thanks,

Darian

XJS or XJ12 center section will bolt right in.

Recently got a whole Jag rear for $160.00 at P&P.

I switched over my Jag rear to Dana gears. Not a huge issue. You need a Dana carrier, Dana 44 gears, and the normal rebuild items. The only catch 22 is the front bearing and the yoke/flange.

The Salisbury set-ups had a 7/16" bolt holding the ring gear to the LSD unit. The Dana 44 uses a 3/8" bolt. That would be the only thing weaker/stronger about the two units. I have never heard of anybody breaking the ring gear off the LSD.

I have a complete unit with 4.56 gear LSD if you really want to rip the tires loose!

I'm currently looking into taking the Salsbury posi unit from my 3.54 diff and putting it into my 3.31 diff.

With parts and labor it may be cheaper to just buy a taller diff with posi already in it.
i have to look up an old thread on another forum, I recall a specialist yard in So Cal selling complete rears at a good price, so just a center section should be even less.

'84 XJ6 is unlikely to already have a posi in it.
'74 might but the the bodies have all rusted to bits.

I will post or PM the link to the specialist if I locate it.

Both those gears should use the same carrier.
The posi is a PowerLok which has 4 spider gears. The cross shafts ride on a 45* ramp. It is a rather positive design and sturdy. Preload can be adjusted by various stack arrangements of the clutch plates. All plates are steel so clutch life is a bit longer. The carrier halves are bolted together which makes assembly easier. I used #120 of preload in my MG and think it will work well but it makes the car difficult to push. This will decrease somewhat with wear.

Jim

That should be pretty easy. Just pop out the LSD carrier and the open carrier, switch the ring gears and re-install it. Check for backlash and adjust if needed. As long as you do not remove the pinion gear, it is pretty easy.

Pretty certain that used gears should remain a matched set for long life.

Still looking for the Jag specialty vendor link.

What gears are you looking for Richard? The ring and pinion are a matched set and cannot be interchanged with other gears, The spider and side gears do not matter as long as they fit properly. The carrier comes in four series' depending on gear range and must match the gear ratio. A search will bring up the crossover points.

Aftermarket gears and other parts for D44 are reasonably priced and can be used with Jag, given certain considerations such as bearing changes and bolt sleeves or hole enlargement. OEM Spicer gears are the hardest and wear the longest. They are also the least forgiving on setup. Do not use racing gears unless service life is not a concern.

Loads of info out there if you search for it.

Jim

Trying to locate a factory 3.07 power lock rear.
Cheaper than modifying what I have by the time gears are bought and installed.