Hello All,
I have been doing a bit of research on GT6 transmission options.. I
have concentrated on two areas, stregnthening the original box and
replacing it with a Toyota one.
Of the two options, the Toyota seems to be by far the nicer way to go.
Reasons follow:
1. cheap boxes, the ones used are 2T, coming out of a Corollla. I am
given to understand that there are aluminum and cast iron versions, with
a weight differential of about 15kg
2. reliable boxes. The Toyota gearboxes are reputed to be very strong,
with the 2T good to about 200hp/180ftlbs, and they last a looooong
time. Allegedly you can just get one from a wrecker, change the oil and
pop it in, no worries.
3. nice final ratio of about .86 seems to be better option than an
overdrive to me….. all of the published ratios for the 2T are :
3.58 2.02 1.38 1.1 0.86 with a stock non-OD diff this
would bring highway cruise RPMs down a good bit.
Of course, originality suffers, but not much at all. The driveshaft
(propshaft) must be modified to fit, and a crossmember bracket has to be
fabricated. All in all it seems to be very reversible. All of the info
I have is supplied by Conversion Components, in New Zealand. As far as
I know they are the only ones who make a conversion kit for this kind of
application.
I talked to the owner for a few minutes and he was very helpful… sent
off some spec sheets and a really nice original photo of the complete
kit. It includes a custom bellhousing and everything needed to do the
conversion aside from the above mentioned things… he includes a speedo
cable and clutch plate to fit as well.
The price for the complete conversion kit, minus the tranny itself, but
including shipping, worked out to USD 698 using an exchange rate of 1.7
NZD:1 USD
USD 1095 for the tranny too, also including shipping
Still, this is more money than option #2:
I spoke with John Kipping, of Triumph Spares fame. He was also quite
nice and obviously knows a LOT about these gearboxes. His contention is
that the weak point in all these boxes is the bearing on the nose of the
Mainshaft, where it fits into the Input Shaft. Sure enough, this is
where mine is blown up.
He offers a rebuilt box for about BP 300, including shipping and core
charges…… this beats the pants off of VB, they want USD 700 plus
shipping.
He is very willing to do custom work, special ratios and whatnot… and
he also has his magic trick for improving reliablilty: on the Input
shaft he bores several (2 or 3) hole from the root (middle of the
groove) into the bearing cup. This forces oil down into the bearing as
the gears mesh, he claims it helps a lot. Mostly he does it for the
overdrive boxes only, but will do it to any if you ask.
Oh yeah, he also says he offers a complete conversion to J-type
overdrive for about BP 500 delivered, requiring only a custom driveshaft
to fit.
Both of these guys also had lots to say about trannys for wide-chassis
(TRx ?) Triumphs too… if anyone would like a copy of the Conversion
Components package, let me know, he sent extra.
SO: the Question
What does the collective wisdom of the list think I should do? $700 is
a fair bit, on my (student) budget, but the driveability/reliability of
the 2T box would be nice… but I can get the parts to fix my current box
much cheaper. I don’t think I want to go with an overdrive, but am
certainly willing to hear different viewpoints on that.
Anyone who is thinking of doing one of these conversions yourself can
mail me directly, I was told that we could get a better deal on the
conversion kits with a group purchase.
Oh yeah, and other than the chance of a group discount, I have no
financial interest etc in either of the companies mentioned.
Thanks for all your time!
Aaron
72 GT6 (tranny in box)
ackleya@hq.7arcom.army.mil
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