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7/10/2012 7:51 am  #1


Jag IRS rebuild questions

Hello everyone. I have a 1979 Jaguar XJ6L lump (Chevy 305) that I bought a few months back and have been slowly rebuilding. I am pretty comprtable with all of the suspension rebuild and motor work is no issue, but I have never reall had a need to rebuild a diff or change gears. With that said, my Jag has the 3.31 non-LSD diff and from the look of the carrier it is leaking pretty bad. It isn't making any noise yet and feels smooth so I don't beleive any damage has been done yet. I am building the car up to drop a 5.3L LS and 4L60E in it, and need to get the diff in good shape. So on to my questions.

1. Where to find parts to change it to a LSD with 4.11's or similar gearing? I have seen so many posts in other forums but no definitive answers. Some people say it is just a Dana 44 others say it is different and the bolt holes need to be sleeved, also something about the spline on the axels. I know that the jag splines are 19 but I know little about how that affects me.  The Diff cover, is this just done with a gasket sealer, or is there acctually a gasket out there for it? I also found a helpful video about rebuilding the outer hubs but I have only been able to find the main bearings, not any of the pivot bearings or seals. Any point in the right direction there would be great. Thanks to anyone that can help out here.

 

7/10/2012 8:21 am  #2


Re: Jag IRS rebuild questions

Well a little more searching and I think Ifound what I was looking for. I can't post a link to the exploded view with parts numbers because I don't have enough posts but glad I found it.

Still have questions around the gearing though.

Last edited by Lancer-AM (7/10/2012 8:21 am)

     Thread Starter
 

7/10/2012 10:48 am  #3


Re: Jag IRS rebuild questions

This should help a lot!

http://home.bresnan.net/~dazed/JaguarIRS4.html

At least it did when I was rebuilding one differential like Daze.

Mustsed


Nothing is impossible, some just cost more!
 

7/10/2012 11:47 am  #4


Re: Jag IRS rebuild questions

With respect to the gearing, there is a size change on the carrier at ratios above 3.73.  Since you're going to change the ratio and want Limited Slip, you won't have to worry about the ring gear having different size bolt holes.  Get the Detroit locker or other Limited Slip of choice for a Dana 44 and your gears, you'll be good to go.  Since you'll have the whole thing apart, you might as well change out the input shaft as well to use a more standard yoke.

 

7/10/2012 4:09 pm  #5


Re: Jag IRS rebuild questions

Welcome from the Jag forums - I wonder how many of those guys have seen this forum before?  Also, check out the Jaguar IRS picture thread - there are soooo many good ideas there.

As stated above, you can swap out ring and pinion gears to go from your 3.31 up to 3.73.  After 3.73, the practical solution is to get an entirely new carrier assembly for gears deeper than 3.73.

When you're talking about sleeving bolt holes, I believe you're talking about mixing in non-Jaguar components from other Dana 44 differential from other manufacturers.  If you're willing to stay at 3.73 or lower, you can avoid that altogether by starting with a Jaguar Dana 44 carrier from a Jaguar.  You'll probably want to buy a new/different carrier anyway because you'll probably want some sort of limited slip.

I think you should buy this.  It is bad-a$$.  And it should fit your car.  I would buy it but I'm too far away and shipping makes it cost-prohibitive.
http://irsforum.boardhost.com/viewtopic.php?id=299
More info:
http://irsforum.boardhost.com/viewtopic.php?id=56.

I know you plan on using some wide rear tires, so you might be able to make good use of those taller rear rotors and 3-piston calipers.  With deep gears and traction, those reinforced LCAs (lower control arms) wouldn't be too bad, either.  Further, if that rear really is from a 1981 Maserati Quattroporte, it has either a 3.07 or a 3.54 rear end - maybe even limited slip - which you could leave for now or swap up to a 3.73 if you wanted to.  You're going to need to rebuild your rear end anyway (bearings, seals) so an extra $150 for a ring & pinion to get you to 3.73 might be worth it.

-Dave

 

7/11/2012 6:36 am  #6


Re: Jag IRS rebuild questions

Thanks guys I think I have it. let me review

So if I stay at 3.31 or move up to 3.73 I can retain my original carrier and purchase a locker for a Dana 44 with a 19 spline setup and it is a bolt in affair. (or do I need to make a gear change from the original Jag gears for this to hold true as long as I stay at 3.73 or under?)

Anything higher than 3.73 and I will need a new carrier (non-jag)

I am unsure about changing the input shaft, I will need to post pictures of what is in there. The driveshaft on the car is not stock. It is a custom 1 piece made to accommodate the SBC 305/TH350 swap so the input shaft may be different, unsure at this point as I have never really looked at the stock to compare. (These things are part of the problem when buying someone else's conversion.)

As far as the other guys coming here, I am sure a few do. These are the kind of questions I don't like to ask on the other boards though. Even in the lump section I got a bit accosted for asking about spacing for a 9.5" rim. Most of them would tell me to go find a locker from a junk yard, which isn't a bad idea, and may be cheaper, but I would really like a better gear ration for quicker launches.

     Thread Starter
 

7/11/2012 12:01 pm  #7


Re: Jag IRS rebuild questions

Lancer - if you're going to purchase a Detroit locker anyway, you might as well go for the gear combo you want.  You won't have to worry about sleeving the ring gear or drilling out the carrier, both will have 3/8 in. bolt holes.  Any Dana 44 gear/carrier (internals) with a 19 splines setup will (at least I don't know of any exceptions) work inside the Jag housing you have.

The key difference between a Dana 44 and the Jag internals is, the Dana 44 has 3/8 bolts which mount the ring gear to the carrier while the Jag has 7/16 bolts which mount the ring gear to the carrier.  If you like your existing gears (doesn't sound like it), you could get a Detroit locker and drill out the 3/8 holes to 7/16.  However, most folks would rather not (me included) because if you ever re-sold (not likely) the carrier, you'd have a small market to re-sell to.

With respect to the input shaft, a stock Jag will have mount which bolts to the input shaft and mounts to your drive shaft.  The change I'm referring to would make the input shaft look more the connection to your drive shaft look like you would see on a standard diff.

Please post  a pic of your Jag rear and someone should be able to advise on the input shaft.  Maybe you've already had the conversion done.

 

7/11/2012 5:15 pm  #8


Re: Jag IRS rebuild questions

Lancer-AM wrote:

So if I stay at 3.31 or move up to 3.73 I can retain my original carrier and purchase a locker for a Dana 44 with a 19 spline setup and it is a bolt in affair. (or do I need to make a gear change from the original Jag gears for this to hold true as long as I stay at 3.73 or under?)

The locker will be a totally new carrier - if you buy a locker, you will not need your carrier.

Lancer-AM wrote:

Anything higher than 3.73 and I will need a new carrier (non-jag)

Correct.

Lancer-AM wrote:

I am unsure about changing the input shaft, I will need to post pictures of what is in there. The driveshaft on the car is not stock. It is a custom 1 piece made to accommodate the SBC 305/TH350 swap so the input shaft may be different, unsure at this point as I have never really looked at the stock to compare. (These things are part of the problem when buying someone else's conversion.)

I just took my old driveshaft to the driveshaft shop and they took care of it.  I can't remember if they reused the old end or ordered a new one.  They can probably do the same for you.

 

7/13/2012 8:19 pm  #9


Re: Jag IRS rebuild questions

I appreciate everyone's help. Finally figured it all out. Since I am putting the aftermarket locker in I can pretty much choose whatever gearing I want. Previously i was under the impression the carrier was the diff housing. I am pretty confident in my ability to do it all just need to learn the ins and outs. Taught myself how to rebuild my transmission and after that the rest is all down hill. I have to hold on the rebuild at the moment though as I am prepping a 5.3l LS and 4l60e to go in it to replace the tired 305/th350 setup in there. And 4.11 gears would really make me hate life in a 3 speed tranny.

     Thread Starter
 

8/15/2012 10:23 am  #10


Re: Jag IRS rebuild questions

Yesterday, I found Curt Hamilton of Hamilton Automotive Industries in Van Nuys, CA. Curt has been converting Jag rear ends since 1967 for use in hot rods.

My problem was bent wishbones (LCAs) from a prior accident. He was able to put them into his jig and confirm they were bent. He can straighten them easily with heat applied and letting them cool in the jig. I left with two straight wishbones. I have three Jag Lumps and the '71 XJ  had been hit pretty hard in the rear and just had the frame properly straightened. The toe out problem due to the bent parts is the last thing to be fixed.

They are very hard to measure accurately without large calipers and I determined mine were bent about 2+MM on the drivers side and 1+MM on the passenger side. Curt's jig confirmed these measurements.

He normally uses the jig to hold and then check them after cutting them down 5 inches or so for hot rod use. He can do and does everything you can think of
with a Jag IRS. He has all the gear ratios for them in stock!

A great resource to find and he has a lot of experience and a fully equipped shop.


'71 XJ6 383/200R, '72 XJ6 LT1/700R For Sale $6500.00,'74 XJ6 383/700R For Sale $3000.00
Glendora, CA, United States
 

9/14/2012 12:33 am  #11


Re: Jag IRS rebuild questions

I take it they don't have a website?


97' C5 Corvette, 46' International Harvester K3 Street Rod

46' International "Harvester of Sorrow" Build Thread
http://www.killbillet.com/showthread.php?t=24127
 

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