Hi all, 1995 XJS, AJ16, ZF - Presuming it has 3.54 gears now. Thinking of doing LS3/6L80E new crate engine/trans this winter, would be wanting to change out rear end to at least the 2.88 from the V12, or higher if possible - keep hearing rumours of a 2.73 DANA 44 gear set used in Jeeps, but all I have found so far is reverse rotation sets used at the front axle..
Biggest question - will an earlier inboard brake unit work with the current outboard brakes? Otherwise, I have seen threads on swapping inboard to outboard brakes, so I would assume it is possible to bolt in an inboard brake suspension unit, only issue then would be the ABS. Easy enough to plumb seperate lines to the individual inboard calibers, but not sure about wheel sensors - anybody know compatibility? Or ditch the entire ABS, wouldn't break my heart.
If possible to use the diff from an inboard car, does it need to be recent? Or will a Salisbury or actual DANA interchange?
I had assumed I would go through whatever I put in, weather it was a complete unit, diff only, or just a gear set. Don't mind buying a new carrier if needed if doing a gear set - I have done gears in a past life, but only big truck stuff, nothing this small - just unfamiliar with the interchanges on these parts.
Or if anyone has anything for sale or trade, located Vancouver, WA, don't mind driving a bit if needed.
Thanks in advance for any and all help,
Mike

 

if you are gonna use the 6L80E , question what gear ratio is the overdrive in the transmission?
if its high enough that would make a nice final drive ratio! all my numbers are with DANA 44 rears!
i use ,NOW, a rear LSD ratio of 3.78-1 , in over drive it figures out to around 2.61-1 final!
i guess it would be interesting to find the overdrive ratio on a 6L80E GM wikipedia site!
ron

 

The differentials themselves are the same, the difference between inboard and outboard brakes are where they are mounted. The inboard has a bracket that bolts to the diff, if you have outboard brakes simply don't bolt those brackets onto the diff. Be aware than most XJS from roughly 1987ish ( I'm not sure of the exact year) use a sensor mounted to the rear diff cover for the speedometer, earlier cars or an XJ6 will not have that. There is a toothed wheel pressed onto the centre section to give the signal.

There were some XJS around 1988 that have a 2.87 Dana diff, not the 2.88 Sailsbury. They are different, and parts are harder to get. I'm not 100% sure if they interchange, or if things life the halfshaft lengths were different.

For what you wan to do, simply swap the differentials. Of course, that requires complete disassembly of the rear suspension, but it's a good chance to refresh things while you're in there.

The Dana 44 gears can be made to fit, but it's not a direct bolt in. The ring gear bolt sizes are different and will require spacer sleeves, I believe carrier face spacing is different and for sure the pinion splines are different. You may require a new driveshaft if you go with Dana gears, and for sure a different yoke arrangmemt. The easiest path is to find a XJS diff in the 2.88 ratio, fortunately those are very common.

 

Thanks, I was hoping, that the diff's were the same casting and axle stubs, I just wasn't sure. No worries on dropping the whole rear suspension, I had planned to do that anyway, mounts are getting a little tired, bushings are original, and, you know, while you are under the car, might as well do anything you can, right? At least with me, it either gets the quickest patch possible, or the other extreme.

Thanks again for the quick reply,
Best Regards,

Mike

 

Ron, 6L80E OD is about 0.67, Corvette actually runs a 2.59 with that trans, turns about 1600 rpm at 70MPH. 2.88 will give me about 1700 rpm at 70 mph, with stock Jag tire size, sounds low, but engine has 325 ft lbs torque available at that rpm, best I can tell, the AJ16 has well less than 200 ft lbs at 2300 rpm ( engine speed at 70mph with current 3.54 gears). Shouldn't have a problem pulling that gear, economy is good, and with the six speed, next gear down is 0.85. Part of the reason to do this is I actually use the cara fair bit, have a small one-off camp trailer that I pull, about 1600 lbs loaded. Last trip over Loveland pass, I was down to 2nd, struggling for 40-45 mph, desperately hugging the right shoulder. That high altitude really kills you. I have looked for something with a higher OD ratio, but even the current 10 speed is still only 0.65.
Thanks for the thoughts, though, I appreciate the response.

Mike

 

Spec on a 4.0 AJ16 is 245hp @4800rpm, 289 ft-lbs @4000 rpm. If you're towing at altitude maybe you really want an XJR?

 

Kinda been pulling teeth with the GEMS 6 over the years, getting to the point that I am tired of playing with it.I like the car, happy driving it, my wife likes it, but I do like the idea of (at least the powertrain) brand new. Still have "Paws", the X358, for the Jaguar experience, if the LS3 dumbs it down too much. There is also "Tank", the Mercedes R350, "Scoot", the A3 Audi, "Wags", an X-type estate, the Navigator, and three Fieros - I am really not going to tell her I am buying another car - but thanks for the suggestion.

Best,
Mike

 

Have you considered the "Andy Bracket"? It advances the timing by about 5 degrees, and on the XJR it gives about a 25 ft-lb boost in torque at 2000 rpm and 12 HP gain between 1500-3000 rpm. It was developed by the engineer at Jaguar who mapped the ignition advance curves.

Nearly everyone who has tried it likes it and reports more power and between 1-2 mpg increase in fuel economy. It's probably the best bank for the buck for bolt on power. A long thread is here, email address near the end : https://www.jaguarforums.com/forum/x...engines-66536/

 

Jagboi, just looked at this thread again, saw that I had not replied to you - sorry - I really apologize for that - I thought that I had.
Yes, I did look at that bracket a while back. The car has always had a little pre-ignition around 1750-2750, at part load - maybe 30 to 60% - although for some reason it goes away above about 5000 ft altitude. I have an AEM fuel/ignition aftermarket modifier out there, left over from another project. I did think about the bracket (or probably make one - I am a machinist, among other things), to give an overall advance, then use the AEM to pull timing where I need to.

But, in the end, the shiney new LS3/6L80E Connect and Cruise is sitting in the garage, hope to pull the car in tomorrow.

Thanks for the suggestion.

Mike.

 

fast40 , it all sounds good Ls3, 4l80e,, except it aint a V 12,, V8s sound great but , nothin compares to a V12 at 7000rpm, with loud exhasts!

all 12 cylinders exit from 5 inch outlet!
i run a Corvette 700R4 OD , with 3.73 gear,ratio custom posi unit!, final drive ratio 2.61-1!

 

First thing I noticed was the door handles - nice job. Yes, V12 is special - trying to talk a friend out of a Beemer for one of the Fieros. Connect and cruise is sitting in the garage, wife is out of town for a week, should get to start tomorrow.

Mike

 

If you’re swapping to a 2.88, I’ll trade you. Got a 2.88 and wanting a 3.54. 88 xjs v12

 

@fast40driver - is this the engine/transmission you'll be using? Make sure you document this swap - I'd be interested in seeing how it turns out.

 

Thorson, yes, it's sitting in the garage right now, Just started a thread today, LS3/6L80E Install. Banes 333, I will send a PM,

Thanks,

Mike