Overhaulin' a Jag diff myself?

[staleg]

Hi!
Since I will be using a 6 speed transmission in my car, the 3,54:1 jag diff I have now will lead to way too low rpm (rear tires are 295/50-16.)

A better suited ratio will be 4,09 or even 4,56.
I have the opportunity to buy for cheap an empty Jag carrier and a set of used but good 4,09 gears.
How much work is it to assemble this myself? I know I will be needing an overhaul/installation kit for something like 120 £ and spescial tools to remove the old bearings and put in the new ones, but besides that, is it simple? Shimming and stuff? Are there anywhere I can read about this?

And one more thing: I've read that it is possible to use Dana 44 gears in the Jag diff, but that it require another overhaul/installation kit. Is that true? Any of you who know where to get this kit?
And will Dana 44 gears with 4,56 ratio fit in the empty 4,09 carrier, if I decided to go for that alternative?

Thanks!

[claude3c]

you could try lookin at this it may help

http://www.myds420.info/servman/AKM9...s4.51-20.m.png

[staleg]

Very informative!
Thanks.

[wilf]

Staleg,

Few of us here attempt to overhaul these diffs ourselves since there are a number of "tricks of the trade" involved, not least spreading the case to get the crownwheel carrier bearings out and back in again.

There are some specialists who do this work, one notable person on this forum who does it is our own Russell Ram, you could try PM'ing him.

HTH

PS - you might get a better spread of gear ratios just sticking with a 5 speed box perhaps?

[staleg]

Thanks for the advices. I realize this is an operation that require some expertice. Problem is that the freight cost from UK to Norway are rather high due to the weight of a carrier. Actually I get lower freight costs from The US than from UK!

Since I have the T56 gearbox and my chassis is all finished I will stick to it. The car will not be on the road in a while. Still lots of work left, so I'm not in a hurry. At this stage I'm just checking different alternatives including buying a complete and used 4,09 or 4,55 on Ebay.

Worst case I just use the 3,55 diff I have. The only problem will be a useless 6th gear and a useable overdrive (0,75) in fifth.

[Happy Jim]

Originally Posted by staleg

Worst case I just use the 3,55 diff I have. The only problem will be a useless 6th gear and a useable overdrive (0,75) in fifth.

I also have the T56 fitted and am currently running a 3.31 diff - it's definatly a bit on the "long" side with 100Mph hovering around the 2000RPM mark, on the flip side economy is great at stupid speeds (I came back from Germany to UK at 120-130Mph and got 27Mpg ).

That said, I've also got a 3.54 diff ready for me to tackle and fit at some stage to make 6th a bit more useable.

Jim

[staleg]

In addition to that I might have larger diameter on the rear wheels than most Cobras(?) Tire dimension is 295/50-16. close to 27" in diameter.

And even more important: My engine from the start will be a near stock 200hp Chevy 350. This engine will not be so useable at very low rpms that the much stronger motors you guys have in your performance cars.

[Clarkson]

Originally Posted by staleg

In addition to that I might have larger diameter on the rear wheels than most Cobras(?) Tire dimension is 295/50-16. close to 27" in diameter.

And even more important: My engine from the start will be a near stock 200hp Chevy 350. This engine will not be so useable at very low rpms that the much stronger motors you guys have in your performance cars.

It might just suit a stock low reving chevy.

[Purple AK]

My Cleveland is basically stock. But with a 3.31 diff it still pulls from 1000rpm with a 0.63 5th gear on 245/55 x 16 rears And returns 29mpg on a run

[staleg]

Ok. I might just slow down a bit. If something shows up, I'll have a look. Otherwise I keep it as it is.