5 Speed Gearbox Conversion

In early September of 2006 I was out doing a carb test run. 4th gear @ 5000 RPM along a straight farm road, something let go. Early inspections showed a failure of the bell housing. Further examination proved it was a U joint failure. The bell housing and rear housing had taken the brunt of the damage. Aluminium vs cast iron. From what I can figure, the shaft must have locked, the moment I felt and heard the problem, I got out of gear and off the power. Still the transmission twisted taking out the bell housing. I was lucky to get out of gear when I did, the cracked bell housing caused the slave to move off the arm, in fact I lost the clutch rod. When I removed the shaft I could not detect any issues with the diff. Only further testing will tell.

Prior to the failure I had been investigating a future gearbox purchase. The concessions was to run with the stock box for as long as I could, while searching for a 389 diff and then purchase a J Type Overdrive kit from Canley Classics. £845 + £300 for shipping. A 5 speed conversion was high on my wish list, but many Triumph owner's were recommending I go for the OD to remain faithful to the GT6. I was in agreement, specially since all the 5 speed kits I'd seen involved a lot of modification and the shifter was not near the stock location which was important to me. Then a few UK friends pointed me to Frontline Spridget who offered a kit which was the same cost as the OD option and altered to retain the stock shifter location.

When the failure happened I acted rather quickly, in hind sight the gear box could not be faulted, but I still do not regret the purchase, it was the same cost as the OD kit, it will be quieter, smoother, more efficient and in 10-15 years I will still be able to still service it.

I found a used bell housing and rear housing from Spitbits, so I will rebuild the 4 speed for "future" back up usage, I'll get the drive shaft checked out and balanced.

Stay tuned too see how the install goes and we'll see if this was a smart purchase.

(Update, I saw this recently on the Canley Classics site. Bottom of the page.)

All overdrive conversion kits.
Recent price rise won't be the last, getting increasingly difficult to source core, and any core sourced is generally in a very poor condition! As a result new part content of the kit's has rocketed in this past couple of years making any profit marginal. With equivalent Ford 5 speed kits costing anything up to double the price of an overdrive kit (and 5 speed stuff is very cheap to source/recondition) we make no excuses for playing catch up.

5 Speed Transmission Summary

30 Nov 06 Successful Project
I've declared the install conversion over to a 5 speed transmission a smashing success. Mike and I went for a nice run with Bob, it was a good time to put the 5 speed through its paces. See the photos, see the videos. As expected it performed very well. The 5 speed gearbox compliments the GT6.

1. No more Willies Jeep whine, at 4000RPM in 4th gear you can hold a conversation.

2. Very smooth shifting, I was worried about the gear ratios, but they work well with the GT6.

3. It has taken the GT6 to a new level and I think its a great conversion for anyone considering it, just pay attention to the details if your doing a GT6.

There you have it, I have no regrets on this one at all, I can't wait to enjoy the GT6 in 2007.

5 Speed Build Notes

03 Oct 06 Installing Parts
Installed the clutch, I will have to come back and do the bolts with locktite. The speed cable was interesting, found if I tightened the speedo end down too much the cable would lock. I wonder if its too long at the end.

05 Oct 06 5 Speed Conversion Session #1
Over all I'm super impressed, you'll see from the night one install pictures. The kit is very well made, it took me a bit to understand a few pieces with regard to the clutch bearing, but once I figured out I had to remove the ford one. It all went well. Did the first page in under 3 hours. Next is the install. Tools, look for a brake hex bit. There were no torque settings in the manual, but your working with an aluminium plate, so locktite everything and good hand tightening with a ratchet does the trick. On the bell housing, you'll have to drill 2 holes with a 3/8" bit and on the top right hole, you'll need to grind down the old bolt location to get a smooth surface. See the picts for details. I need to buy some gear oil and Ford electrical hook ups for the reverse switch.

06 Oct 06 5 Speed Conversion Session #2
Session 2 was less enjoyable. I've encountered mounting issues and will have to fab my own mount. Also will need to do some grindings. Jon Wolfe confirmed he had to do the same, he's going to snap a pict of his mount, I'm thinking it will be a T shape unit. Tapered at the end because the mount is up close to where the frame curves up. Pictures from session #2.

-1. Spigot bushing, this is the "pilot" bushing which is inside the crank. To remove it, I had to pull the clutch and flywheel. We used a small drill bit and tapped the old bushing out, it more or less cracked apart. Be careful not to damage the crank. Once it was out, I cleaned the area up. Oiled the bushing and inserted. Then reinstalled the fly wheel and clutch. Locktite and torqued all bolts.

-2. Cutting away the tunnel, the new gearbox measures 31", so I had to remove a section in front of the brake handle. I'll make a new piece of curved metal and screw it down.

-3. Mounting issues. On the driver's side there is some contact between the frame and gearbox, I'll grind that on session 3, hope I don't have to weld. The other major problem as I mentioned above is the mount. The plate in the stock location interferes with the box, holds it up. The mount on the box is in totally the wrong location. The Spitfire guys do not have this problem, I think the bell housing is shorter.

-4. This one burns me the most, the whole idea behind spending $$$ on the mod kit was so I would have a stock location shifter and not have to modify my tunnel at all. I don't see how this is going to work. Very disappointing. We'll see happens. I figure I'll have to modify the cover.

So I ended session #2 thinking, should have listened to my wife and bought the OD kit.

07 Oct 06 5 Speed Conversion Session #3
Session 03 Team Rousseau Mod stopped trying to find a fix and just made them. Pictures from session #3.

-1. The frame, cut out 4 notches in the frame. Nasty to do, but totally required to clear the gearbox and mount.

-2. Narrowed the mounting plate and tapped 4 new holes, 2 on the frame.

So I'm in a hell of a better mood now. We put the old box together and measured from the flange to the bottom of the mount. 5", after we were all done and the new set up showed the same. I think by the end of the weekend I should have the car running again. Over all I am pleased with the kit, but I think Frontline really needs to address the GT6 issues. The plate for certain, a different design would easy to come up with and the tunnel. I'm going to have to chop mine in half. I'm still glad I have the modded gearbox. I saw Jon's and the shifter is back near the hand brake. I think it would make shifting for me very hard, my elbow would be a rather odd position.

09 Oct 06 5 Speed Conversion Session #4
Session 4 was a long day, but at the end of it the GT6 ran under her own power. What a different feeling transmission, I need to adjust the slave to improve the clutch point, but other wise WOW, quiet and very quick off the line. Pictures from session #4.

-1. Finished off all the bell housing bolts.

-2. Put gear oil into the system.

-3. Installed the drive shaft, its so tiny. Greased both u-joints before installing as well the shaft.

-4. Topped off the diff while I was there.

-5. Installed the exhaust, had to remove the camber bar to do this, so we could get the system to sit lower to clear the gearbox.

-6. Starter motor installed, clutch slave was installed, I will add extra washers behind the slave to improve my clutch action. Can't get into gear cleanly on the first try.

So what's left, clutch slave as I mentioned. The reverse switch cable will be extended 7" with new connectors and the tunnel will be cut in 1/2 and lengthened.

Over all on the first lap around the block I'm pleased. Can't wait to take her out and open it up again. Its way quieter, no more Jeep whining sound and damn with the 411 diff she's going to fast off the line.

Session 5 will be later this week. Stay tuned.

11 Oct 06 5 Speed Conversion Session #5 (No Photos)
Tonight we connected the reverse switch cable, which works. Added some washers to the clutch slave, now all gears engage cleanly. And finally the tunnel cover was cut in two. A piece of heating duct aluminium has been used to lengthen the cover. As well some changes are being made to where the shifter comes out. I did not take any pictures, will get them when all the work is completed. Session #6, I will complete the cover, tie down the rev switch and speedo cable, install the radio mount and clean the car. Almost done.

22 Oct 06 Clutch News
Well I screwed up. If you look at the photo you will see I installed the clutch bearing backwards. The resulting error caused the bearing to bounced off the clutch cover, I'll pull the gearbox again and fix the problem I still have the org new bearing and cover if required. More to follow. I made a suggestion to Frontline to add that note in the install doc, yes I should have seen this, but it happens. So a quick tip tech note would have been helpful.

07 Nov 06 Removing Parts
Tonight was nice and mild outside, so Dad and I pulled off the exhaust, drive shaft and several bolts. The gearbox will come out this weekend after the 11th. I am hoping the damage is only on the bearing. But we'll see. Note, when you remove the shaft, some oil will come out from the gearbox, but not a lot. I stuff a rag in there and put a plastic bag over top of it.

12 Nov 06 Bearing Swap
So this one was pretty simple, pull the box and swap out clutch bearings. Took about 4 hour and I pleased to say it worked. I went back to the stock GT6 bearing. If you look at the pictures you'll see the stock bearing is taller then the supplied one. The reason I did this is for the clutch slave. With the smaller bearing, I had to use some washers when mounting the slave. Now the set up is like stock and it feels right. Topped off the oil levels. So the conversion is all but done, just need to fix the tunnel. Pictures from session #6.

5 Speed Gearbox Photos

29 Sept 06 Gear Box Arrival

My order of a 5 Speed Gearbox from Frontline Spridget arrived today, everything looks good.



05 Oct 06 Gear Build Session #1

The bell housing is installed, page one of the Frontline instructions are completed.

06 Oct 06 Gear Build Session #2

Flywheel removed, bushing in, clutch, cutting and then mounting issues.




07 Oct 06 Gear Build Session #3

Frame trimming and plate grinding. Team Rousseau Mod was in full effect.

08 Oct 06 Jon Wolfe's Install Pictures

Jon sent me some picts to help me along. Shows the diff between the stock T9 and modified T9.




09 Oct 06 Gear Build Session #4

A solid day of work, she moves.

12 Nov 06 Bearing Swap Session #6

Like the title says, pulled the gearbox out and put the clutch bearing the correct way.



5 Speed Gearbox GT6/Spitfire Modification

The stock Ford Type 9 gearbox is long (shown) , you are required to make alterations to the tunnel and metal work on the car. Frontline offers a modifications which shortens the linkage section of the gear box. I opted for this.

Frontline Spridget 5 Speed Gearbox Specs

I was concerned about the ratios, but after talking to a few users, the 2.0L gearbox will be fine, very spirited with the 411 diff.
I may look for a 3.89 down the road. The 2.8i box would have been better, but according to Frontline it would not work. See
* Minty Lamb Gear Speed Calculator. Tyres 195-50/15R.

GT6 4 Speed Gearbox with J Type OverDrive Ford Type 9 5 Speed Sierra 2.0 Ford Type 9 5 Speed Capri 2.8i *
Ratios: Ratios: Ratios:
1st 2.646 1st 3.65 1st 3.36
2nd 1.779 2nd 1.97 2nd 1.81
3rd 1.254 3rd 1.37 3rd 1.26
4th 1 4th 1 4th 1
OD 0.797 5th 0.82 5th 0.82
Diff 3.89:1 Diff 3.89:1 Diff 3.89:1
OD @ 60 MPH = 2768 RPM 5th @ 60 MPH = 2837 RPM 5th @ 60 MPH = 2837 RPM
6000 RPM: 6000 RPM: 6000 RPM:
1st 39.3 MPH 1st 28.5 MPH 1st 31 MPH
2nd 58.5 MPH 2nd 52.8 MPH 2nd 57.5 MPH
3rd 83 MPH | 3rd OD 104.1 MPH 3rd 76 MPH 3rd 82.6 MPH
4th 104.1 MPH 4th 104.1 MPH 4th 104.1 MPH
4th OD 130.1 MPH 5th 126.9 MPH 5th 126.9 MPH
Diff 4.11:1 Diff 4.11:1 Diff 4.11:1

OD @ 60 MPH = 2924 RPM

5th @ 60 MPH = 2997 RPM 5th @ 60 MPH = 2997 RPM
6000 RPM: 6000 RPM: 6000 RPM:
1st 37.2 MPH 1st 27.0 MPH 1st 29.3 MPH
2nd 55.4 MPH 2nd 50.0 MPH 2nd 54.4 MPH
3rd 78.5 MPH | 3rd OD 98.5 MPH 3rd 71.9 MPH 3rd 78.2 MPH
4th 98.5 MPH 4th 98.5 MPH 4th 98.5 MPH
OD 123.1 MPH 5th 120.1 MPH 5th 120.6 MPH

* The transmission used for the 5-speed kits is from the 1.6 to 2L Ford Sierra.
The larger engine Ford gearboxes are not suitable as their first motion shaft is too long.

5 Speed Gearbox Links

Frontline Spridget - Manufacturer of the kit I purchased.

Josh Bowler's Spitfire - Used the kit, but sourced his own transmission.

Dave Powell's Spitfire - Used the kit, but sourced his own transmission.

Jon Wolfe's Racing GT6 - Used the kit, but sourced his own transmission.