1984 XJ6.0 Turbo

The Christmas miracles continue. I enabled the speedo output in the Holley with the default 4000ppm signal, wired it up, and we have a speedo!

I did have to apply a correction factor of 2.0 via the DD app which means that the Jaguar speedo is looking for a 8000ppm signal. Now, I need to figure out what I want to do with the rest of the auxiliary gauges (fuel, temps, etc) and clean up this mess of temporary wiring.

What an awesome feeling seeing the OEM tach and speedo just “work”.


How is the rear end holding up with the added power?

Funny you should ask. Did you see my posts on the facebook pages?

First “issue” with the car since the swap was done - original diff gave out. I was coming home one night and started to hear a knocking from the rear end consistent with vehicle speed. Figured it might be a driveshaft issue, but decided to chance it and limp the car home.

The chassis is an '84 with 172K on it, but the rear end assembly has “85 XJ6” written on it in ink marker so I am assuming it was swapped out some time in the last 39 years. No clue on the mileage on it though.

Drained the diff. This gear oil has only a few thousand miles on it.

The rear end comes out as an assembly so 2 hours later I got this.

The folks in Quality Assurance came by to check my work

The culprit is the retaining pin that holds the cross shaft in place, which walked out and allowed the shaft to knock into the pinion.

Pinion took a little beating

It’s a shame because I think the 2.88 ratio suits the setup very well, so I am reluctant to regear. The damage is in a non contact area so maybe I’ll deburr the pinion teeth and see how it runs.

I hammered out the cross shaft (shouldn’t have to do that) and found that it had pretty bad galling on the spider surface. Definitely a lack of oil at some point which caused it to get mega hot.

I actually had to hammer out the cross shaft halfway, cut off the exposed stub, then hammer out the remainder as I obviously wasn’t able to pull it out with the carrier flipped.

Thinking back, when I dragged the car home it was on the back of a tow dolly since there were no car trailers available due to Covid madness:

Even though the original trans was probably going to be scrapped, I still unbolted the driveshaft from the pinion flange so that it wouldn’t cause anything to seize up and lock up on the thruway. Once I got the car home and up on the lift for the first time, I drained the diff and only a few ounces of gear oil came out.

My theory is that it drained out due to a bad leak on the driver’s side output shaft while in storage before I bought the car, it got very hot on the way home, and then I continued to beat it to death with new oil for the next 2 years behind the LS.

Game plan - try to salvage the ring and pinion, order an Auburn locker, replace bearings, and put it back together. I’ll also check on the condition of the output shaft bearings, hub bearings, and various seals while I’m in there.


weld up the spiders and make it a spool! Roadkill style

Tempting…when I pulled off the cover and saw the cross pin all buggered up, I definitely eyeballed my welder across the garage with bad ideas…but alas, this is a street car and the wife and kids wouldn’t enjoy the skipping and chirping of tires in the church parking lot

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Well, I hit a snag as both my research and DTS indicated that there is no Eaton Truetrac available for my 19 spline output shaft application. They only make one for a 30 spline found in DANA diffs like in Greg’s car.

So, my options are:

Find a Dana diff locally and get the Eaton Truetrac.
Purchase Auburn 546085 (superseded 5420112) and install into existing housing.

It’s near impossible that I would find a Dana diff at a junkyard within a few hundred miles, and would likely cost more than just rebuilding mine with an Auburn. It’s a shame Eaton doesn’t offer the 30 spline option, I was looking forward to the Torsen technology, but I suppose any limited slip is better than my open diff.

I did also get the carrier/ring gear and pinion gear out - the damage is worse than suspected. There are small bits of material missing on the leading edges of the pinion gear. Normally I would feel comfortable just polishing the burrs and reinstalling, but a failure here could cause the diff to lock up (not the good way) at speed. DTS has a used 2.88 they’ll sell me for $100 once I figure out the path I want to take. I’d like to tackle the gear install myself.

Thoughts from the experts?

In general, things tend to get more complicated as they evolve, so I would start with the simplest solution, like the $100 Salisbury.
From what I know Dana parts are impossible to find.

Are you going to be doing donuts or driving in snow?

Not planning on driving in snow Aristides, but with over 500 ft-lbs on tap, I’m always searching for any traction I can get.


Apparently, Torsen’s for Dana 44s can be had…

Paul, I appreciate the link, but that is for a 30 spline (Dana style diff). Mine is the GKN with drain plug which has 19 spline outputs. Unfortunately incompatible.

Would it be possible to find a Dana 44 pumpkin to put in the cage? Changing driveshaft ends is relatively trivial

I used info from the link below when changing my E-type diff from 3.54 to a DANA 3.07 gear set. I have no idea if it has anything helpful to you, but you might take a look at the Jaguar IRS section in particular.

DazeCars, Ford Galaxie Mustang tech and restoration

can you use an XJS rear center section with the Power-Lock limited slip?
i did that in my series 1 XJ6 and one day will do the same on the '87

I’m trying to recall the guy we had/have here that was racing a S1 with a big blick conversion years ago. A Kiwi or Ozzie? All I can recall is that the XJ was white and properly built.

Made a video about my last build, 2011 Crown Vic with the turbo LS. Give it a watch (Jag content at the end).


I am about ready to begin reassembly of the rear axle assembly. This quick differential refurbishment quickly turned into an overhaul of everything - hubs, half shafts, stub axles. Nothing really had any functional issues (other than the differential obviously) but I couldn’t stand to put greasy components back in the car with unknown service history.

That being said, does anyone have part numbers for Dana 44 carrier shims and the crush collar?

Upside is that I have been filming nearly every detail and will be putting together a nice video documenting the entire process.


Would be nice to see!

As one should.

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After installing a 454 Chevy in my 86 XJS, I pulled it and went to a 327 Chevy, much better drivability & rpm. The big block just felt like it would defeat the rear suspension, it was excessive torque that I couldn’t keep my foot out of it. Been enjoying the SBC XJS for 15 years now. No problems. Currently, I am running a Chevy 4.3 V6 in my 1980 MGB, with a 700r4 and narrowed Ford 8" rear. What a bullet! Love doing these swaps.


Getting apart the IRS was dirty, tough work. This chassis is remarkably rust free but it seems the rear end was worked on at some point since I found evidence of a rebuild in a few spots. Driver’s side hub carrier assembly missing the bronze phosphor spacer ring (huge endplay), the words “85 XJ6” written in paint pen on that same carrier (this chassis is an '84), and some missing tie wire.

I spent the better part of a few weeks trying to get the hubs out of the carriers. My person 12 ton press and a friend’s 20 ton press were defeated even with the use of a torch to melt the loctite on the splines; it took a 50 ton press at a heavy truck shop to get it loose. Unfortunately the end of that hub was damaged beyond repair, but Dave @ EverydayXJ saved the day with a spare.

Another week was spent beating/pressing off races and bearings and cleaning. Both my carriers exhibited the cracks that seem to be present as a result of the casting process.

I dropped those off for welding and reinforcing, and while I was waiting busied myself with other items.

Originally I wanted to reuse my 2.88 ring and pinion since the long gears were great on the highway and loaded the engine nicely, which helped spool the turbo. Since the original 2.88s were destroyed when the open diff let go, I purchased a used set of Jag 2.88s from DTS in Detroit. Unfortunately, I found out that these gears are not compatible with the Auburn 546085 19 spline Posi limited slip. They physically bolt up to the differential carrier, but the flange is too close to the pinion and will not allow the carrier to be mounted.

I have to give credit to Bill at Rear End Specialists, who worked with me to find a solution. He was patient and welcomed the challenge as he had not done a gear and carrier swap in a Jaguar Dana 44 before. I recommend his services.

A well known shop local to me, Denny’s Driveshaft, came through with a new set of Dana 3.54 gears and the required 26 spline pinion yoke. They are located 10 minutes away from my axle builder, so no shipping was required, and Bill picked up the parts from Denny’s for me. Big thanks to both shops for helping me out.

Once I got the diff back, I started the process of building it up. I rebuilt the output shaft assemblies with new seals and installed the rotors/calipers.

The diff cover got cleaned up with fresh paint. I noticed that the breather vent had some mangled threads, so I welded in a stainless 1/8" NPT elbow for the vent to mount to.

I designed a set of conical differential to cage mounting sleeves. My OEM bolts on top of the cage were tight, but I figured this was an easy way to ensure the diff wouldn’t come loose due to the lack of thread engagement with the OEM bolts.

1/2"-13 threaded studs were trimmed to size, installed with blue thread locker, and self locking nuts installed on top of the new spacers to ensure alignment.

Winter is wrapping up here in Buffalo, so I got my other fun car out of storage and ready for the warm season. The summer is the first where my son is old enough (2) to face forward, which makes it much easier to load him into his seat. He and my daughter cannot get enough of “Blue Car”.

Next up: Axle carrier rebuild, full u-joint replacement, fulcrum shimming.


I really like that mounting scheme you came up with for the differential to the taco shell! That’s great, out of the box thinking!