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5 & 6 Speed Transmission Conversions

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5 and 6 Speed Transmission conversions

Supra 5 Speed Conversion (Also read article regarding the Dellow's kit & FHC/OTS)

I just received a letter from Dellow's in Revesby, AUS. These are the folks who do the conversions to Supra 5 speeds. The cost is $955A for the kit, and $575A-$675A for the transmission. The kit includes bell housing, clutch, pressure plate, rear crossmember, speedometer cable, pushrod, yoke, and clutch fork, etc. They will sell the kit only, allowing you to locally source a transmission. Looks like the only welding is to the prop shaft. They will ship worldwide. They also supplied a fact sheet on the Supra transmissions. There are 4 gearing variations available (See the Table below)

There are four possible stick positions: 18", 19", 20 1/2" and 21", as measured from the front of the box. They recommend the 18" box. Dellow also supply a "Qik-Shifter" for $160A which reduces shifter throw by 50%.

Contact information is: Dellow Automotive Pty LTD, 37 Daisy Street, Devesby, NSW 2212, PO Box 43 Revesby North 2212, (02) 97743873 fax: (02) 97744783

Late 80s XJS 5 Speed (Getrag 265)

If it is a late 80s European XJ6 then it would be the Getrag 265 with manual take off drive.. If so then that is the box to have.. You will need a mounting plate to bolt it up to the bell and lower locating brackets as well... (George Butcher makes the adapter plate.. SNG Barretts sell it.....) )the tail section is longer than the space allowed so you will want to relocate the center cross member or cut through it and then restrengthen .. The gear lever will come out about 1/2" behind original...

Be careful on servicing the box.. Getrag have built in a special destructive mechanism to the box if you open it in the normal way.. See a knowledgable fellow at BMW to get it right... as they were allowed to service the boxes...

T-5 Manual Conversion

In the latest Jaguar Journal, on page 28, there is an article about a T-5 manual conversion kit developed by Predator Performance. There is a choice of 5th gear ratios available. One of the guys at Predator Performance has a '69 E-type with a 0.73:1 fifth gear - 2500 RPM at 70 mph with a 3.54 rear. Cost from $3400 to $4850. Available through Terry's Jaguar Parts at 800- 851-9438.

Which is Best?

I picked the Vicarage set up because it is the least intrusive option: Supra 5's, Getrags, and Richmonds seem to all require cutting or interior changes. GTJ claims that their Richmond box does not, but if five speed is an indulgence, then a six speed is a total waste. The Vicarage box only requires shortening the driveshaft and converting the speedometer to electronic drive. Should be easy enough to reverse, if you wanted to.

Which is Best? #2

1. ZF. I bet none of you had ever considered a ZF box for this swap. But Jaguar did. Just after the E was introduced, Jaguar ran a number of tests on a five speed ZF in the E. They concluded that while the box was good, 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. I have a letter out to ZF, to see if they have something modern that would drop in. I will share the response, if I get one, with the list.

2. Jaguar overdrive. It is possible to take the overdrive unit from a Mark X and bolt it up to the Jaguar 4, but this requires modification of the floorpan, which I was unwilling to do.

3. Getrag. At one time, Jaguar offered Getrag 265's on Euro-spec XJ6's. These are excellent transmissions, in spite of what you may have heard. They are tough, fairly reliable, and modern in every sense. They are also becoming impossible to locate. I know of three or four shops which offer Getrag conversions, but this is one of the more expensive options. When you look into it, you generally find that the shop has had one or two of these on the shelf forever, awaiting a deep-pockets conversion. Once the current supply is gone, I don't think these will be available again.

4. Toyota. This was a tough one for me. My everyday car is an '88 Supra, with the perfect W58 transmission. Unfortunately, it is still too nice to break. Let me back up a bit. The Toyota swap is facilitated by Geof 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. Of course, I might be able to cobble up a linkage to bring it out in the right spot, but this would require a lot of experimenting, and remember that I am paying a commercial shop to do the work. 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.

5. 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 accomodate 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 power rating on the BW T5WC is about 300HP, making them just adequate for the application. These boxes have a poor reputation in ultra high performance applications, so do not go racing with a BW! I toured the local junk yards, and I can report that most of the boxes I found were the long-tail versions. The only box I found with the correct stick postion was from an '86 GMC Jimmy...I just can't sink that low!

6. JT5. The JT5 is the BW T5WC, with all the appropriate changes. The short tail version is used for SWB cars, while the long tail is available for V12's. Several gearing options are available, some of which are perfect for the application. By all accounts, this is as close to a bolt-up as it gets..the shifter position is almost spot on to the original Jaguar 4! The short tail version does not have room for a speedometer gear, so it is equipped with an electronic sensor. In this case, your speedometer head will need to be converted to electronic as part of the swap. I am told that the workings fit in your old speedometer, and there is no visible change. If you can use the long tail version, no speedo mods are required. The long tail may work in 2+2's (Charles...another reason to step up). The JT5's are manufactured on a limited basis...current capacity is about 30 per year. All in all, this is the best set up for me....the gearing is exactly what I want, the conversion is out of the box simple, repair parts are easy to find, and the manufacturer is still around. I will be going with this. If you choose the JT5, be aware that the same box is available from several sources. While the box is the same in all cases, there are differences in the amount of preparation and set up done by the vendor, price, and the amount of customer service available. So shop around.

7. GTJaguar 6 speed. I never really considered this seriously. The GT Jaguar six speed is a close ratio racing-style transmission. Only sixth gear is overdrive. I believe the box is built by Ricmond Racing, and modified by GTJ for a good fit. Too expensive for me.

8. Tremec 3550. This is a very high performance transmission meant to replace the BW T5 in racing applications. It is made in Mexico. I have not researched this extensively, since it can accurately be described as exotic. Available thru speed shops.

Important dimensions of the Syncro 4 speed:

Front to end of tail 12.25"

Front to transmision mount center 12.75"

Front to shifter center 12"

Front to end of input shaft 7"

Pilot bushing diameter .492

Gear Ratios of Various Options
 

#Several OD gearing options available, from .59 to .82

*The five's of that era were close ratio, but not overdrive transmissions.

+Prototype transmission used in various special Jaguar cars, early '60's

Supra 5-Speed conversion Testimonies

• I was tipped off to the Dellow's kit by Robert Dingli of the orignal Jag-Lovers list. I am including his post below. He is very happy with it, but his experience is with auto to manual conversions. I still haven't found anyone who has done this from 4 to 5 speed. I can tell you (as the owner of an '88 Supra) that the box is strong and trouble free. With the right rear axle gearing, it is very clean from first thru the gates, even with the 'huge' jump to second. You are right about not being able to start cold in second. My non-turbo Supra gives about 200 net horsepower, and 190 ft-lbs of torque, which is probably close to the true output of the 4.2L Jag engine.
• I converted my '74 XJ from a BW65 slushbox to a Supra 5 speed and have been very happy with the results. The car definitely performs much better as expected. I have also had the opportunity to pull the Toyota gearbox apart for an input shaft bearing replacement), and found no signs of trouble despite many tens of thousands of kilometres of hard driving. As for performance results, a friend of mine in Brisbane replaced his V12 auto trans with a Supra 5 speed and cut 2 seconds of his 1/4 mile times before breaking a uni joint.

Ford Option?

The Borg Warner model 12 auto in the V`12s is very similar to the Ford FMX trans. I wonder if the AOD will bolt onto the bellhousing or AOD with bellhousing will bolt onto the V12 block?? Might just be a great solution.

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