89 XJS v12 (Marelli) 5 speed swap

I actually can’t see the pics on my phone for some reason, but good on him having the earlier car and the rope. I hate the later seal.

FYI I updated post #29 with link to bellhousing source.

There were several things on the docket for today. The first one was a vacuum line and wiring clean up. I wanted to replace the vacuum line that feeds the ECU, I don’t know how you’d possibly do this with a transmission in place. It was surprisingly in good shape, very pliable, no sign of any deterioration. I discovered that all of the plastic clips that are supposed to hold the hard line up to the tunnel were broken. I don’t see how this thing could not have been rattling, although I don’t really recall noticing a rattle under there. Here are the before and after pics, I put the new vacuum line through a piece of 5/8 inch heater hose to offer some abrasion protection.
The picture at the bottom is the vac line from the transmission running to the right side rear intake manifold, and the kick down switch, both of which will be removed. The new ECU vac line is sticking up in the center.


Item 2 was replacing the pinion seal. The pinion seal leaked when I got this diff, which is out of about a 69 eType. ( I wanted the 3:54 gears. I still have my 2.88 diff and will send it off for a regear someday.). I decided to wait until it was in the car, cause it’s easier to get the pinion flange off when the diff is held by the car.
I marked the pinion and the nut so I could get the preload back to where it was. More on that in a sec.

I had to use my 1/2” breaker bar extended with my jack handle. Could’ve used the impact but didn’t want to. Pinion flange holder courtesy of Dads tool box.

Pinion flange looked good, no grooving.

This is a trick Dad taught me years ago for removing timing cover and pinion seals. Drill a small hole, run in a sheet metal screw, then use some wire and a lever to pull it out. Worked like a charm. (I don’t own a seal puller at the moment.)

The old seal had this paper gasket behind it. The new seal comes with sealing goop on it

Sealing surfaces looked good.

Done. @Dick_Maury please: should I stop now that the witness marks are lined up? Or should I torque to a spec? If so, what’s the right torque? I am thinking this generation of diff uses shims and not a crush sleeve, so guessing I should torque it? Thanks!

One more thing. If you do this job, don’t be a dumb sh!t and use bolts to hold the pinion flange tool that are too long to extract once the flange is seated. , You’ll be spending some quality time with your cut off wheel. That is what happened next, I chose to not memorialize with photographs.


The FedEx guy showed up this afternoon with a box from Summit. I took a break to unpack and admire the shiny new parts. Two challenges surfaced. One expected, one not.

First and expected challenge: The MedaTronic bellhousing is cut for a GM transmission, which uses a smaller front bearing retainer, about 4.67 inches. A Ford front bearing retainer, which is what I’m using, measures about 4.90 inches. This was not a surprise, Paul Cangialosi told me this several years ago when I bought bellhousing. He said some customers choose Camaro T5 transmissions, and this being a universal bellhousing, he made it the smaller GM size, and it’s up to the customer to modify the front bearing retainer if they are going the Ford route. We’ll put the new front bearing retainer in the lathe and turn it down to fit. There’s plenty of edge material available, and that can be done quickly and very accurately, versus trying to set up the bell housing in the mill and open up the hole. The reason I already have the front bearing retainer is that it is included with the Ram hydraulic bearing kit. I am not exactly sure why, I will investigate the difference between this one and the stock retainer when the trans arrives.

Second challenge, unexpected. The clutch does not fit the fly wheel. The fly wheel bolt pattern measures 11 and 5/8 while the clutch is 11 and 3/8. I called Ram, but they are closed this week. I called Summit, they tried to help, but that dimension is not provided by Ram.
After some time with the Google, I learned that Ford 10 1/2 inch clutches use an 11 3/8 bolt pattern, and GM 10 1/2 inch clutches use an 11 5/8 bolt pattern. I did not originally choose a GM style clutch, because they are frequently 26 spline and I need a 10 spline to mate with my Ford-style transmission.
Turns out that GM clutches can be bought either way, so I ordered a Ram 10 spline, 10 1/2 inch disc, 10 5/8 bolt pattern from Summit. Should be here tomorrow. The new clutch is actually cheaper, so I splurged on overnight shipping to get it here. I want to get the flywheel and the pressure plate over to the machine shop to be balanced, which will take a couple days.


See below my experience with the pinion preload, mine has the crush sleeve though.
I would suggest you play safe and put it back as it was, especially if the diff does not make any noises.
If you want to experiment go over the mark only a couple of degrees and see.

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Thank you, Aristides! I will line up the marks. Dick recommended the same. It did get very tight just as the marks came into alignment, so that seems good as well.

This morning I popped over to Dad’s (O.K. it’s a 90 mile drive so not quite able to pop over) to turn down the new front bearing retainer to fit the bellhousing. The bellhousing measures about 4.680” and we cut the retainer to 4.677” which gives a nice slip fit. If you do this job obviously take your own careful measurements. You can’t easily restore material you cut off. We removed about .230” from the overall diameter, so about 1/8” from the edge.

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When I got home the new clutch had arrived. It fits great, so that’s a relief. After I confirmed the fit I took the pressure plate and flywheel to the machine shop to be balanced as a unit. He said expect 3-4 days but he usually beats his estimates. I updated poste #28 with the correct part number.

Talked to FedEx this morning and the trans should be here Thursday. That will allow me to mock everything up so I can cut the shifter hole and figure out the rear trans mount. I had a epiphany about the mount, I now think it will be pretty straightforward. We shall see.


Geez - your dad just happens to have a handy metal lathe available at his place? :open_mouth: What does he do for a living? :confused:

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I’d be guessing a retired engineer or tool maker.
It’s what we do;

This was matching the taper in the rear wheel as Jaguar different lengths of outer drive shaft, the part that connects the inner drive shaft to the hub. I couldn’t understand why the half shaft nut would not fully wind onto the thread.
It’s not easy to see the difference in these shots but definitely not the same castings;

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Hey I’m an anaesthesiologist and I wouldn’t be without my lathe and mill.

I’m sitting on the 3/4" steel top on my welding bench, and you can’t see the blasting cabinet and parts washer in the part with the hoist.


Yep, looks like the garage of our old home before dad expanded operations considerably … ended up with one of the largest tool & die/tooling design businesses in SW Missouri before it all ended … :triumph: I guess I just didn’t have his aptitude for such things … :slightly_frowning_face:

He’s a gunsmith, mostly retired now as he is 87. There is not much he can’t do with a mill or a lathe.

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This morning we’re back inside the car doing stuff that is pretty much unrelated to the transmission swap. Namely, I need to remove the old cell phone and figure out some stereo wiring.

(If you’re only reading for transmission swap stuff there is none in this particular post.)

This car came with a dealer installed cell phone, an absolute necessity for the Busy Executive in 1989.

Inside the car, while you’re on the road, your cell phone is instantly available in this convenient armrest pocket.

It connects via a fat multi pin cable, routed underneath the console in along the transmission tunnel to this sleek modern unit in the boot. There is also antenna wiring and hands-free microphone wiring.

But wait! What if I need to take a call from away while I’m away from my 1989 Jaguar XJS? Did I mention that I am a Busy Executive?

Do not worry! We have you covered. Here are the components out of the car. The boot unit has a sweet docking plate with one touch removal of the black box.

Also Included with your luxury performance car purchase is the mobile half of your mobile phone. It has its own antenna, battery, and convenient cigarette lighter plug.

You simply unplug the handset from the console, and undock the black box from the boot and reassemble using the convenient carrying unit. It has a handle and a shoulder strap.

If you happen to be in the middle of a call when you need to make this transition, they are going to have to call you back.

As an added bonus, when you are carrying this unit around, no one has to wonder what kind of vehicle you drive.

Cmon. You know you want to be at a Power Lunch in your double-breasted suit with the latest power tie yelling “sell, dammit sell!” into this phone.

Full disclosure. I had a small car stereo business while I was in college, and I had the car-only version of this phone.


Had one of those in the 2000 XJ8 VandenPlas. But it was in the console, so cover down the console was an armrest. As I understood things, that phone was not compatible with the then current cell providers. I took it out and fashioned a new bottom for the interior of the console.

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I had a “car phone” installed in my 88 Tbird. Very useful in my business…

A PO installed one in my 94 Jeep Grand Cherokee. Only the hand set is missing . MNIc on teh A post. Wiggly antenae oin the rear quarter window. box undder the passenger seat

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Carried the Novatel bag phone equivalent, with battery pack, 89 to 96 - was well worth it back then - unfortunately became unusable with arrival of digital signals.

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Had one back in the day also. My girlfriend at the time worked for AT&T in NJ were they were making them at the time. Had it hooked up in my 1982 BMW Barvaria, it was a big honking thing much bigger than yours. OMG :scream:

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Interesting, as my dad was also a gunsmith, and in fact he had originally hoped his tooling company would expand into an arms co., but that never happened. That’s fate I guess … :slightly_frowning_face:

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