Hello All

I saw this on FleaBay and wondered what it would take to make this (or something like it) work for me? Can parts (rear drive and bell) be swapped from the trans I have now, to pretty simply, make another 400 work?

https://www.ebay.com/itm/324090243929

I'm just running thru ideas here. I have a ways to go, but because of the money reality, I have to start planning well in advance.

What say you?

 

The 'bell" is the entire transmission main case.

You'll have to remove all the innards from this transmission and reinstall them into your Jaguar case

Here's a better link

https://www.ebay.com/itm/TH400-autom...MAAOSwtyxeXRUw

Cheers
DD

 

Thank you, Doug! I honestly had no idea...
I have a lot to learn...

If my knowledge met my willingness,,,
well that would be a goooood thing.

 

if it was me , i go with a GM 700R4or 4L60E, gives you an overdrive!

 

I see a lot of "cases"... How hard are they to stuff, Ron? ICS and I recently met,,, and I think with his help/guidance it would be possible...

How does one know if the bell will fit a 1990 xjs? That's the question... Well, one of about 3000 or so

 

The Jaguar bolt pattern is unique so you'll either need a transmission that was made to go behind a 5.3 V12 or you'll need an adapter plate.

And bear in mind that not all GM cars/transmissions had the same bolt pattern. The adapters I'm aware of will adapt a Chevy bolt patter transmission to a Jag V12.

Cheers
DD

 

Also worth noting that the bolt pattern from the 5.3 HE V12 and the 6.0 V12 is not the same, so a 4L80E from a later 6.0 or XJR will not fit an earlier 5.3.

 

Ok... So I read a good bit on John's and have a LOT of learning to do. But,,, this is just me seeing if even thinking about any of this makes sense... Yeah, so, I was looking at this and wonder what people think? This kind of thing, with the conversion kit from Johns... Even remotely on the right track here?

https://www.hawksmotorsports.com/cam...onversion-kit/

 

How good are you with fabrication? You'll need to create a pedal box and find a master cylinder that works, you'll need to design and build a rear crossmember, as the GM one won't fit the XJS, and you'll need to figure out the speedometer, as the XJS transducer won't fit the T5. It's been done, but it's not simple or straightforward. If you're looking for bolt in, this isn't it.

 

Jag!!! Dude. Thanks for keeping it right up front with me..

Your question - Not so good... But was with a guy the other day who has been and is working on an XJS with a manual six speed,,, and another guy who has a garage (well they both do) let they both weld and work with metal... And,m let me tell ya,,, when I saw (and imagined) that facelift XJS with the placed clutch and shifter, heard it running with smartly mod-ed exhaust,,, well yeah - it got me to thinking.

With help,,, somewhere down the line, I think it would be possible. Been getting familiar (as much as one can) with digging into the th400 and the 700 watching guys who know what they are doing on YouTube... And,,, getting more and more used to a grubby set O hands. I think I can,,, with help.

Laying best plans - haha, and you know what they say about that 😱

 

Really tho Jag.

I'm sure things will kinda break and settle in with my CherryPie... The car has not been truly driven for a long long time. But still, after driving her the few times I have - I think I would like and need a 4th gear or an overdrive... I read some of Johns,,, the guy who supplies upgrade tranny parts, descriptions of why a upgrade makes sense, and they rang true. We'll see. I'm in no rush... We'll see

https://www.johnscars.com/qb/v12qb.html

 

Also,,, let me add - I came across the 5speed kit (above) by accident searching around.. And, btw, I have an electronic speedO that I cannot get to work anyways. PITA

​​What I am really thinking about is the Johns kit and a t700... With help, I don't really think that that is WAY beyond doable for me... I have a LOT to learn, yes, and will need help, guidance, advice. What definitely IS doable at this point tho is, while driving CherryPie thru the summer, top down, having a used t700 on a bench and carefully rebuilding it. Right, I have NEVER done ANYTHING like this before and the innerdz of the trans,,, all the little (and big) bits and pieces, is daunting x4... Lol,,, I'm sure I could take it apart ok, but getting it back together is a different story.

I will be going to Pittsburgh at the end of April and it looks like there are 2 places along the way that have an abundance of the 700 transmissions for super cheap... Would need to know what and where as far as getting my hands on all the RIGHT rebuild guts to make it a solid unit worth replacing what I have with... Again,,, dreaming and planning ahead. Is there a single rebuild KIT for the 700?

From John --- "Transmissions manufactured before 1993 are suitable. An excellent choice would be a unit from an 87-92 Camaro/Firebird Tuned Port (TPI)."

Anyways... We'll see.

 

Its worth noting that https://www.motorlegends.co.uk/ now has a 6 speed kit using Ford's 6speed ZF clone and US Shift's trans controller (not sure what model car's ZF/Ford they're adapting from). The kit's cost isn't cheap though.. about double what it would take to use The Driven Man's 5speed TKO conversion - and maybe their T56 6speed manual kit (if they'll still supply it.)

The TH700R4 isn't a bad idea, BUT it wouldn't be a bad idea to give it a performance rebuild. They're weak transmissions from the factory - or at least they were in the late 80's and 90's. Put them behind anything with torque and they eventually break. We had a diesel 6.0L Chevy which broke two of them, and they were known to not be too robust without being given a good run-through with performance parts. Having rebuilt my XJS's TH400, I'd probably give a rebuild a go with a junkyard one myself before installing behind the V12.

I had a FANTASTIC TH400 guide book, and lived in a location where I could go to a wholesale trans parts dealer to buy whatever uprated sprag or roller bearing I needed (OEM) so I was lucky. I suspect there are some very good TH700R4 books out there, and they'd be worth a full read-over before settling for sure on a 700R4. I'm not sure if the torque converter comes in a performance version, but given problem can occur in the 1:1 lockup circuit, it'd be worth asking the question - forums/books etc.

A couple of guys went with a diy-ish conversion with cheap-ish T5 transmissions out of Mustangs for their V12's and some people have been through multiple OEM transmissions as they're weak as well (without performance parts) ... reports of clutch forks breaking on hard shifts, synchros messing up.. etc... There's a very good thread in the archives here outlining exactly how to do a conversion, BUT just know that T5 might not last long w/o performance parts.

The 4L80e as noted only fits the 6.0L as Jag added some meat to the engine rear pattern to make it fit. That said IF you have a 6.0, you CAN drill it to the 5.3L pattern if need be, but I don't think.. at least without an adapter - the 4L80e can fit the 5.3L at all.

Back manual trans availability, there's an outfit down under in Au called Dellows that's been around for years and sells quite a selection of Bellhousing adapters for the V12 to put various flavors of manual transmissions behind it.

~Paul K.

 

What does the Driven Man use for a flywheel? Mind you, I have heard some not very nice things about their delivery schedule.

Dealing with TV cables on a 700R4 isn't the easiest either, and absolutely critical to get the adjustment right. A 4L60 with an aftermarket controller might be better, but more $$$.

 

Re: Flywheel. IDK. I'm not sure if they're custom made for him, or if they're some other off the shelf unit.

Two version offered:

https://drivenman.com/product-category/flywheel/

Yes, it's clear that there have been times where some folks have had problems with his supply time line. I think that it's a good indication that lots of questions need to be asked up-front, but not necessarily a reason not to deal with him. IDK what his supply chain or inventory is like. I know Sheffi Keisler (from whom the business originated) had problems supplying full kits in a timely fashion too. (I think Sheffi was getting better $ & steady business from the Chrysler/Dodge American market & focused there) -hence his selling the Jag side of the business to The Driven Man in 2005. BUT from everything I've heard the kit, once delivered, is pretty friggin good, and people are very happy with the conversion itself.

~Paul K.

 

Yes the Jag Turbo 400 is internally the same as the GM applications. Yes, the 400 is not the best transmission for the 5.3 V12 because the 5.3 is a high revving unit, redline starts at 6500 as opposed to most older GM V8s which usually saw peak power at around 4000 rpm. Now that I've been daily driving my XJS I've found that it upshifts smoothly and will downshift with a stab of the pedal. I don't know if my used tranny had a shift kit installed but I think that would be a good idea. I'm sure that it would be quicker if it had an extra gear, but it is plenty good the way it is. Unlike the old GM V8's the power increases as the revs increase over 4000 and approach redline. This is why the car comes to life at speeds over 60 to well over 120 mph. The performance comes from the engine, not the gearing( in this application). This car was designed to be an effortless high speed runner, not a drag racer. The Turbo 400 is a good transmission, used by GM in their best models. Cadillac, Corvette. most big block muscle cars, big block trucks, Rolls Royce and Jaguar too. It was hard enough replacing the stock transmission, I can't imagine fitting bellhousing adaptors and such. My suggestion is to first either locate a known good used transmission, which is what I did. Or have a used unit rebuilt than swap it for the one in your car. You can always play around with the original tranny on the bench once you've got the car up and running. The important thing is to get and keep these cars up and running.Just my two cents.

 

You can adapt your own ( or one obtained from a swap meet, junk yard ) manual transmission etc. There are 3?ways to do it. Buy the kit and have someone install it for you.
One is listed right here on this site along with costs involved while I responded on how I have done it for less. In fact I still have that transmission set up, but the adapter is made for the early block ( 71-77)
But it is a pure race transmission, not something that could be street driven without getting tickets.

Since I don’t know you or your skills and temperament. I hesitate to tell you which to use. Things I find simple might challenge you or be obvious.
Remember Jaguar used a 4 speed manual transmission in the XKE series 3.