It's been four years since a bad transmission left us stranded in our 2+2 on a mountain top in Vermont. The JT5 I installed after that incident has proven to be an excellent modification. This year, I've embarked on a more ambitious project: to create a reproduction of the 1963 LeMans Lightweight E-Type. At first, I intended to install a Jaguar syncro box, as was installed in the original car. But the gearbox was the weak spot that cost Jaguar the race, and ended any serious LeMans effort for many years thereafter. Subsequently, all the surviving Lightweights were recalled to the factory and refitted with ZF five speeds Aside from being incredibly expensive today, these ZF transmissions were no more successful that the original Jag four. I recently had the opportunity to examine an original factory Lightweight...it had been converted to a Moss box, which says something about the original factory choices...reverting to the old box was considered an improvement! So here it is, a car without a transmission, and no clear model to emulate. What follows is a summary of my latest research into transmission swaps.
Why 5 speeds?
The question is different for a road car vs. a race car. On a road car, it is sometimes desirable to have a low rear axle ratio to give better off-line performance. This is why Jaguar fitted 3.54's to many US delivery cars. On the other hand, a low ratio rear limits top speed, so the cars so equipped had no shot at the magic 150 number. Furthermore, running a 3.54 means a fair amount of cabin noise at highway speeds, due to high rev levels. Finally, a low ratio hurts gas mileage.
To drop the revs and gain back what's lost with a 3.54, two options are available: go to a higher axle ratio, or add an overdrive gear. Although more historically sensitive, higher axle ratios are not attractive, since off the line performance is still what counts here in the USA. A five speed (with an overdrive fifth) offers a way to get performance from takeoff to 150. It will also drop the revs at highway speed, giving a quiet ride and better gas mileage. The question is how to do it without dramatically changing the nature of the car: in other words, to add a fifth speed in a way that Sir William might have approved of.
On a race car, the requirement is different. For high speed racing, the rear axle ratio is often very high....LeMans Jaguars had axle ratios at least as high as 3.07, in fact, the highest ratio in the "pit kit" was 2.64! This allowed the cars to achieve high top speeds...170+ was typical for the LeMans E-Types. But this limits performance from a dead stop, so an extra low first gear could be used to compensate. If the gear ranges were evenly spaced, then the driver would find that there wasn't enough gearing to cope with a challenging road course. One possible solution is to add an extra gear, but top gear would remain 1:1. This would allow the use of evenly spaced ratios, and provide a good selection for the driver. The ZF was such a close-ratio box. Note that close ratio doesn't imply that the top gear has to be 1:1, although overdrive close ratio boxes tend to be six speeds. A disadvantage is that more gears add drag, reducing the effective output of the engine.
ZF. Just after the E was introduced, Jaguar ran a number of tests on a five speed ZF in the E. They concluded that it produced too much gear chatter for a refined sportster. But they used it in many of the well-known racers of the day, including the factory lightweights and low drag coupes. The transmission proved to be a problem to the racers....it's very heavy, and places a lot of drag on the motor. There are some anecdotal reports of cracked engine blocks and bellhousings attributed to the stress involved with running the big ZF. (There's one point I'd like to make very clear: ZF was the ONLY five-speed factory fitted to race cars during the E-Type era.)
Jaguar's own 4 speed synchro, in prototype form, was used in the factory Lightweights that ran at LeMans in 1963. It failed miserably, with two cars dropping out with transmission problems. One car crashed, and the fourth car barely completed the race, with first and second gear non operational. All the surviving Lightweights were subsequently fitted with ZF close ratio boxes, which proved to be problematic as has been mentioned. LeMans was lost due as much to the lack of a good transmission as the superiority of Ferrari.
I tracked down a ZF when I was researching transmissions for my Lightweight. It's size and weight is truly astonishing...it took two strapping fellows to take it off the shelf. It looked to be more appropriate to a tractor than a race car. As to the price, well, if you have to ask, it's not for you. This transmission, rebuilt to perfection, will cost more than a good E-Type.
Anyway, the ZF is nostalgia. There doesn't appear to be a modern ZF box appropriate to an E-Type.
Jaguar overdrive. It is possible to take the overdrive unit from a Mark X and bolt it up to the Jaguar 4, but I believed that this requires modification of the floor pan, which I was unwilling to do. I am now informed that this transmission will fit in a 2+2 which has an automatic, and may fit the manual car as well. The source box is the "A" type o/d for a MK2, S-Type, MK X, 420, 420G, XJ6, or XJ6-C. For the Lightweight, an electric overdrive is simply not appropriate.
Getrag. In the early 80's, Jaguar offered Getrag 265's on V12 XJS's. These are excellent transmissions, well able to handle the torque of a V12. The Getrag 265 has a couple of weak points: certain boxes used friction synchros, essentially metallic cones with a high friction coating. Once the coating wears off, no more synchro. Layshaft bearings are frequent wear points. The box has a reputation of being difficult to service. Although there are a few 265's still available in the Jaguar community, the best place to go for one of these transmissions is a BMW specialist, where a rebuilt box can be had at a price competitive with other swaps.
Some vendors are currently selling a Getrag 225 conversion for E-Types. This is NOT the same as the 265, and I have been unable to uncover reliable specifications or anecdotal experience. Conversion appears straightforward...an adapter plate at the front, and a shaft extension at the back.
I once again emphasize that Jaguar NEVER used Getrags in XK-engined racers. In the 70's a Leyland five speed was fitted to some non-export XJ6's, this was an unfortunate combination. And in the 1980's the Getrag 265 was fitted to XJS 12 cylinder cars. This latter combination was first done by TWR, and was very successful, but note that 265's are not offered as a standard kit by any Jaguar vendor.
Toyota. This was a tough one for me. When I did my original JT5 swap, my everyday car was an '88 Supra, with the perfect W58 transmission. Unfortunately, it was too nice to break.
Let me back up a bit. The Toyota swap is facilitated by Jeff Dellow, in New South Wales. He makes conversion bell housings, which allow Toyota 5 speeds to bolt up to XK and V12 Jaguar engines. Knowing how good that Toyota shifter is, coupled with the low cost of the Dellow conversion kit, seemed to make this a natural choice. But the decision became difficult when I realized that Dellow built his kits for 'saloons' and XJS's. Using the most appropriate Toyota box with Dellow's "shifter forward" modification, the shifter would still be 2 inches too far back.
If you consider the Toyota option, remember that the 'best' fit is the W58, which was used on 1987-1992 non-turbo Supras. It is a very limited production box, which may be another reason to think twice. The good news is that once you are set up for a W58, there are many other Toyota boxes, which could bolt up, if you can live with the gearing. I am told by a reliable source that the Toyota swap is only applicable to LWB E-Types, due to interference with the bodywork, hand brake, etc. I have yet to find someone who has actually done this swap. Obviously, all Toyota swaps involve rebuilt transmissions.
There is a new Supra box just coming onto the market. This is the R154 box from the fourth generation Supra Turbos. They are very capable transmissions, and have appropriate gearing. These are currently being evaluated by various vendors in Australia and New Zealand, we await reports.
The shop manual for these transmissions can be found here: http://www.cygnusx1.net/supra/library/TSRM/mt/MT_01.html
Bellhousings are now available from a second vendor, Conversion Components, in New Zealand.
Borg Warner T5 Worldclass. The BW T5WC is a high performance version of the familiar BW T5. It is used in many cars, including Camaros, Firebirds, and Mustangs, so parts availability is as good as it gets. Making this work involves modifying the bellhousing to accommodate the bolt pattern, and making sundry changes to shifter location, input shafts, and gearing. If you wanted a real cheap conversion, this could be the way to go, but be sure you have access to a machine shop and welding equipment. Also be sure to start with the correct transmission. This box comes in long tail and short tail versions, which differ in length by 7", and the shifter location varies by as much as ten inches! In some applications, the shifters are offset from the vertical, just to add to the complication.
The torque rating on the BW T5WC is about 300ftlb, making them just adequate for the application. These boxes have a poor reputation in ultra high performance applications, as a result there are strengthened gear sets available.
Borg Warner recently sold the tooling for the T5 to Tremec. Production has continued under the Tremec nameplate.
For anyone who'd like to go the do-it-yourself route, I've put up a cross reference for Ford T-5 applications, hopefully Chevy will soon follow.
T5WC from a '96Chevy S-10: Correct shifter location
JT5. The JT5 is based on the BW T5WC, but with many changes. It is manufactured by Medatronics. Several gearing options are available. Gears, shafting, and tailcase are custom manufactured by Medatronics, and various modifications are made for reliability and fit. This is as close to a bolt-up as it gets..the shifter position is almost spot on to the original Jaguar 4.
Early versions did not have room for a speedometer gear, and required an electronic speedometer conversion as part of the swap. The latest versions of the JT5 dispense with this conversion, and the stock speedometer may be used. Customers still have the option of an electronic speedometer if they so desire. Note that the Series I and II 2+2's have a different floor pan arrangement than the Series III LWB cars, so be sure to check with the manufacturer to get the correct box. Medatronics reports that the boxes are built up from new parts, which are expected to remain available despite Tremec's acquisition of the T5.
VJT5. This transmission is a shortened T5 WC, produced in the UK for Vicarage Inc. Information on this product will be added as it becomes available.
GTJaguar 6 speed. I never really considered this seriously. The GT Jaguar six speed is a close ratio transmission. Only sixth gear is overdrive. The box is built by Richmond Racing, and modified by GTJ for a good fit. Too expensive for me. This box is a difficult install, requiring modification of the center console.
Tremec 3550. This is a very high performance transmission originally meant to replace the BW T5 in racing applications. It is made in Mexico. When I did my original swap, I didn't research this extensively, since it was not widely available at the time. However, it's now a mainstream box in the Mustang community. The effort of converting this box for Jaguar use is comparable to that required for the BW T5. It has a reputation of lacking smoothness. Personally, I think it's comparable to the Jag Synchro 4 as far as smoothness goes. I would suggest you try one yourself before you commit.
Waterloo TX51. The TX51 is a Tremec 3550, with the appropriate changes. Various modifications have been made to the case, input shafts, and shifter to allow bolt-up installation in an E-Type. A normal mechanical speedometer connection is provided. As of this writing (Aug 2001), the production of this box has been suspended.
Tremec/BW T56. This is a very high performance transmission, used in Dodge Vipers, among others. It is a six speed, and can be fitted out with various gear sets. The standard gear set is a double overdrive, which is really overkill. It's a very heavy box, weighing in at over 100lbs. Unfortunately, there are no vendors currently doing swaps with this box: I have not been able to gather much information.
A few years back I decided to install a five speed in my 2+2. At that time, I chose a JT5. The logic was simple...the 1-4 gearing was very similar to the Jag box, and having a .8 overdrive drops the revs very nicely when cruising. It was an off the shelf conversion, with good vendor support.
Mine was the first early 2+2 to get a JT5, so it was a learning experience for everyone concerned. At the time the JT5 came in two "flavors"": a long tail version and a short tail version. The long tail version was intended for V12 cars, but it had the advantage of a standard speedometer drive. The thinking was that the 2+2 was similar in length to V12 cars, and so the box would work. If I had to do it again, the short tail version would have been the choice. The long tail box interfered with the hand brake mechanism, and it took some manipulation to get it into place. The console required some modification as well.
The result of all of this is that the current shortened version of the JT5 is a better fit. Nobody else should have the problem I encountered.
The box proved to be smooth shifting and trouble free. Reverse is not synchronized, which isn't a problem as long as you remember. There is a 15% speedometer error, which cannot be corrected with new speedometer gears. Having lived with a JT5 for more than four seasons, I can report that I'm as happy with it now as when it was installed. Maybe happier, since I've forgotten how much it cost.
The TX51 is a big transmission, fortunately the Lightweight was designed with a very large tunnel to accomodate a ZF transmission. I doubt the fit would have been as elegant in a regular E. A special bracket was fabricated at Automotive Restorations which allows the transmission to be removed from the top, through the tunnel opening. This can be done without removing the motor. The tunnel was releived near the upper bellhousing bolts to make this easier.
Careful examination of the TX51 showed several design problems. The biggest problem was that the output shaft had been ground into a hex pattern, and the output flange selected to match. Whether or not this flange would have worked is a question I didn't care to answer, so the mainshaft was reengineered to allow a proper splined output flange. This was a bit involved. I have the one and only TX51 made with the .82 overdrive. This turned out to be based on the "road race" version of the 3550, which wasn't well supported by Tremec. In fact, the parts for this box aren't even listed in the Tremec parts book. It took some sleuthing at Tremec to track down the correct part number, and there were no spares available in the Tremec inventory. Eventually, with the help of a Tremec engineer, the part was sourced. Once we had the correct part, it was cut to length and splined. A suitable flange was prepared, and the problem pronounced solved.
Another problem with the TX51 was the rear output shaft bearing and seal, which rides in a machined aluminum "donut". This arrangement was worked over and given an improved bearing and seal. It's still a bit iffy, but better than the original.
Finally, the shifter is an prehistoric-looking thing which probably originated in a truck. This was cut and turned down to match a D-Type shifter knob, and now looks great. It's so beefy, it should be unbreakable.
The cost of all this? Don't ask.
The Lightweight will be driveable in 2003, then we will see.
There's nothing better for an E-Type than a five speed. Coupled with the right rear axle ratio, it really makes cruising a pleasure. But consider the costs and aggravation involved before you leap.
Summary of Transmission Ratios
|Tremec 3550 (TX51)||3.27||1.98||1.34||1.00||0.68||-|
|Tremec 3550 (TX51)||3.27||1.98||1.34||1.00||0.82||-|
|Jaguar Syncro 4||2.94||1.90||1.39||1.00||-||-|
|Jaguar Syncro 4OD||2.94||1.90||1.39||1.00||0.80||-|
|ZF 5 Speed||2.93||1.97||1.45||1.17||1.00*||-|
|Jaguar 4 (racing)||2.98||1.75||1.21||1.00+||-||-|
|Jaguar 5 (racing)||2.82||2.14||1.66||1.27||1.00*+||-|
|Getrag 260 3.83||2.20||1.40||1.00||.81||-|
*These five's are close ratio, but not overdrive transmissions.
+Prototype transmission, never produced commercially
**Early Jaguar Syncro 4's
*Richmond uses adjustable side linkage
##LWB transmissions are 18" front to tail
Sources for Borg-Warner T5 WC Transmission
ABE Transmission and Gear Company
Outside CA (800) 821-0308
Inside CA (800)631-8756
Any Chevy Dealer (Camaro applications)
Any GMC Dealer (light truck applications)
Any Pontiac Dealer (Firebird applications)
Any Ford Dealer (Mustang applications)
Any Nissan Dealer (300Z applications)
Sources for Tremec 3350 Transmission
Dark Horse Performance
16617 SE 134th Renton, WA 98059
(206)227-7778 Fax (206) 277-3893
474 Moody St.
ABE Transmission and Gear Company
Outside CA (800) 821-0308
Inside CA (800)631-8756
Sources for JT5 Transmissions
Medatronics Corporation (Inventors)
1717 Avenida Del Sol
Boca Raton, FL 33432
561 447 9594
Fax: 561 995 9234
Terry's Jaguar Parts
117 E. Smith Street
Benton IL. 62812
Phone (800)851-9438 Fax(618)438-2371
850 Fiero Lane
San Luis Obispo, CA 93401
Phone (805) 544-7864, U.S.: (800) 444-5247
Source for VJT5 Transmissions
5333 Collins Avenue #502
Miami Beach, FL USA 33140
(305) 866-9511 phone
(305) 866-5738 fax
Replacement parts can be ordered from any Borg-Warner source
Sources for TX51 (Modified Tremec)
Waterloo Drivetrain Systems (manufacturer)
6819 Redwood Dr.
Rohnert Park, CA 94928
Sources for Getrag Transmissions
+44 (0)1746 765432
fax (+44) (0)1746 761144
The Heritage Building
Bridgnorth, Shropshire. WV15 6AP
Metricmechanic, Inc. (BMW specialist)
505 East Main
Richland MO, 65556
Phone: 573-765-1269 Fax: 573-765-4216
Sources for Richmond Racing Transmissions
Gran Turismo Jaguar
4285 Main Street
Perry Village, OH 44081
474 Moody St.
Sources for Toyota Tranmsission Kits
Dellow Automotive Pty LTD
37 Daisy Street
Revesby, NSW 2212
PO Box 43 Revesby North 2212
(02) 97744419 fax: (02) 97744783
Conversion Components LTD
17 Victoria Street
Waihi 3061, New Zealand
+64 (7) 863-8509 (Phone) +64 (7) 863-6354 (fax)
Copyright © 2000 by Michael Frank all rights reserved. This page may not be copied for any purpose without permission of the author.