Adventures In Wrenching:
Replacing A Gearbox In A Triumph GT6+
By Larry E. Snyder
This whole mess began in late April. The gearbox in my GT6+ had been weak
since I bought it in November of 1992. It always crunched a bit when going
into second gear, there was no reverse lockout, and the shift lever wobbled
loosely. It was just a matter of time.
Then, on a Monday, it made a particularly gross sound going into second gear.
A lot more than the usual crunch. This time, damage was done. From that point
forward, any time I was in first, second, or third gear there was a noticeable
click-clack and the sound of metal clanging around. Oops.
I got the car home by using a bit of first, enduring the horrible noises, then
jumping into fourth, where there was no problem. It was a long trip home.
I ordered a rebuilt gearbox from John Kipping Triumph Spares in Coventry,
England, and the unit arrived 12 days later. The cost was $343 and some
change, which included shipping and core charge. Thank you, Mr. Kipping! A
rebuilt gearbox from Victoria British was $999.95 plus a $150 core charge,
plus shipping.
Then came the real task at hand - removing the old unit and installing the new
one. My first move was to jack up the rear of the car, put it on stands, and
undo the four bolts and nuts holding the propshaft to me differential. My
intention was to remove the propshaft and get new U-joints. Once I saw that
the exhaust system and rear sway bar would have to be removed to accomplish
this, I decided to forego it for the time being. Don't worry, I realize I'm
most own worst dreaded PO! Having it loose at the diff made it easier to move
it out of the way at the gearbox, though, so it wasn't time wasted.
I then performed the gruesome task of removing the seats, the center dash
support, the carpets, and the gearbox cover. This car had the original fibre
gearbox cover, but it pretty much disintegrated upon this removal. Good thing
I had bought a fibreglass replacement.
With the defective gearbox thus exposed, I began removing the ancillary stuff.
I disconnected the propshaft, the speedo cable, the reverse light wires and
the clutch hydraulic line. My intention was to leave the clutch slave cylinder
on the bellhousing. After draining the oil from the gearbox, I jacked up the
engine with hopes of getting the output shaft flange clear of the propshaft
tunnel.
No way. The bellhousing does not have sufficient clearance at the firewall to
be jacked up very much. So I jacked up the engine as high as it could go with
the bellhousing still clearing the firewall. Then I removed the 5 quadrillion
bolts and nuts holding the bellhousing to the engine (OK, it's about 12 or so,
but it SEEMS like 5 quadrillion!) except for the top three.
OK, here's the tricky part. A friend slid a 2x4 under the gearbox and
supported it while I undid the rest of the bolts. Then I slid the gearbox back
until the bellhousing cleared the firewall. Then I jacked the engine up a bit
more and slid the gearbox back until the input shaft cleared the clutch plate.
Now we had a loose gearbox sitting in the car. We wiggled and worked and
wiggled and could not get the bellhousing to clear the heater core. I finally
removed the clutch slave cylinder from the bellhousing. That's when the
release bearing, carrier, and lever all fell out. Anyway, then I had to remove
the right parcel shelf and we FINALLY got it out. Success!
Next I removed the bellhousing and the shift lever extension from the old
gearbox. I put the bellhousing on the new gearbox and got out my shift lever
extension rebuild kit. It wasn't too hard to replace the springs and bushes
at the end of the shift lever itself, but since the bolt and nut at the other
end didn't want to loosen, I skipped that part, since it felt OK anyway. Then
I tried the lever out on the new gearbox. Wow! It felt great!
Next, the clutch cover had to come off. Even though the old clutch was working
just fine, this looked like a good time to replace it. It came off just fine,
and the old plate fell out. Both looked fine, almost new. I'll save them, but
probably only use them in an emergency. The release bearing looked fine, too,
but there's not point in risking doing this again anytime soon, so it was
replaced.
The Haynes manual showed the release bearing carrier being clamped in a vise
and the bearing pried off with large screwdrivers. I don't have a vise anymore
(*sniff*) so I went all over town hunting for someone who did - with no luck!
I stopped by the auto parts store, but there was no one in the shop, so I went
back home, discouraged. I decided to try to drift the carrier out of the
bearing. I set the bearing on 2x4s and tapped a screwdriver on the carrier.
Three taps and the carrier fell right out of the bearing! I had spent two
hours looking for a vise for something that could be tapped right out! The new
bearing pushed halfway on the carrier, and a couple of taps on a piece of 2x4
over the bearing seated it firmly.
Now, I know this: If the Haynes manual had told me the carrier could be easily
drifted out the bearing, it would have taken a 50-ton hydraulic press to free
it. Guaranteed.
Getting the new clutch plate and cover on the flywheel is a bit tricky from
inside the car. The cover plate is heavy enough to need both hands, but
the locating dowels in the flywheel make things a bit easier. I used the
handy dandy clutch alignment tool ($3.95 from VB) to hold the plate in
position while I put the cover on. All in all, not too bad. Tightened it
all down, and removed the alignment tool. Voila! Ready for the input shaft!
Installing the new gearbox (sans shift extension) turned out to be a LOT
easier than removal. For some strange reason, known only to those trained in
the strange ways of Coventry, the gearbox popped right back in, clearing the
heater core easily. (queue Twilight Zone theme music). Then came the task of
mating the gearbox to the engine.
Again, a helper supported the gearbox with a 2x4 while I worked it forward
onto the engine. It was pretty easy, actually. I had to push the gearbox
forward until it hit the firewall, then lower the engine until the bellhousing
could clear the firewall. But when I lowered the jack to lower the engine, it
stayed put!
I looked all around and under the engine trying to figure out why it wouldn't
come back down. Finally I guessed that the exhaust pipe was jammed against the
frame rail. I put the jack just a little lower, and worked at the pipe with
the official Large Screwdriver With A Lifetime Guarantee. The engine
immediately dropped half an inch. Success!
The engine was then lowered enough to mate the bellhousing to the engine. Some
bolts were put in, and there is was! The new box was in!
Then, on my long drives to work in the '74 VW camper, my mind wandered back to
the clutch plate. The Haynes manual warned that if the plate were installed
backwards, it would fit but I would find it "quite impossible" to operate the
clutch. I decided I had better get the clutch hydraulics working in order to
find out if I had, indeed, been paying attenion. I remembered that one side of
the plate said "this side toward flywheel" on it. It had been made so obvious
I was really beginning to doubt if I had done it right...
I connected the clutch line to the slave cylinder. Now, this sounds really
easy, but I could not get it to line up where the threads were right. It took
me forever to get it on. Once on, I put a little DOT5 into the master cylinder
and pushed the pedal. Purple stuff was squirting everywhere! I cleaned up the
mess as best I could, then realized that the clutch line was torn in two
places! Apparently it had been caught between the bellhousing and the firewall
and been torn up. Ever try to find a replacement from the usual sources? No
one has a clutch line for a GT6. But my friendly muffler/brake shop owner (who
owns 2 Triumphs and 2 Lotuses (Loti?)) made one up for me, no problem! This
guy had made up a front exhaust pipe for me when my old one finally
self-destructed - and didn't charge me! So I repaid him with three tickets to
the Arlo Guthrie concert coming to my theater next month...
I installed the new pipe and tried it out - yay! My clutch release lever
moved! It seemed to travel about an inch - is that right? I mean the part
where the slave cylinder pushes it. I assume the release bearing is moving
more, since it's on the longer end of the lever.
So that's where I am right now. Tonight I will put back all bolts and nuts and
tighten everything. Then I'll fill the gearbox up with Castrol Hypoy, and take
her out for a spin! I'm excited!
This weekend I replace the interior stuff, including the new fibreglass tranny
cover.
Is this the quintessential LBC or what? Here's what I've replaced in 18 months:
1. Differential
2. Water pump
3. Cylinder head
4. Starter
5. Gearbox
6. Rotoflex couplings
7. Heater core
8. Speedometer
9. Parcel Shelves
10. Crash pads
11. Dashboard
12. Paint
13. Brake pads
14. Gearbox cover
15. Windscreen rubber & chrome trim
My wife has told people "Did you know you could get a new car delivered by
UPS? Larry has done it. Of course, it takes a while, and lots of deliveries..."
*Sigh* I must REALLY like this car...
Larry
lesnyd@monsanto.com
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