GT6 diff

Author
Discussion

arh

Original Poster:

1,222 posts

240 months

Monday 31st July 2006
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I have broken my diff, whoops!

My question is how reliable are these diffs? the reason I ask is I am considering buying a secondhand one, and don't really want to change it again if that one fails.

so is it worth it? or should I just buy a recon unit?

yertis

18,090 posts

267 months

Monday 31st July 2006
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Just buy a recon one, not worth the bother of risking a second-hand one although you can change them over in a few hours.

SPORTING BEAR

7,898 posts

235 months

Monday 31st July 2006
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From personal experience I would agree strongly with getting a recon unit and from someone who really knows how to recon them properly

//j17

4,487 posts

224 months

Wednesday 2nd August 2006
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2nd hand diffs are a bit of a lottery. You may get one from a car that was broken due to a rotten body...or you may get one from a car broken because the diff was badgered.

If you go recon then you have two types of recon. Cheapest is the standard recon where the seals, bearings, etc are replaced and the other components examined and replaced in necessary. The problem with this is if the reconditioner considered the gears to be in servicable condition they will be re-used and not replaced.

The best recon boxes are those which explicitly have the gears replaced, which should remove the slight whine worn, but servicable gear diffs can suffer from. They do of course cost more.

If money is very tight, go 2nd hand and accept you might have to buy 3 to find a good one.

If money is OK, but you don't want to spend more than you need to, go standard recon (and fit a sports exhaust/manifold - the noise of that is great and easily covers any slight whine ^_^). If you have money to burn, go the whole hog.

On the whole Triumph diffs are solid old lumps of metal - you generally get through half shafts rather than the diff they are attached to.

yertis

18,090 posts

267 months

Wednesday 2nd August 2006
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This is true. Although I did once have a TR6 crownwheel break up in quite spectacular style on the M5.

jaybkay

488 posts

221 months

Sunday 6th August 2006
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All GT6 non overdrive diffs suffer from carrier fatigue, and Mk I and II overdrive ones have this fault as well. The Mk III overdrive diff is the same as a Spitfire IV.
The best ratio for an overdrive car is a 3.63 from a Spit 1500, a non overdrive car really needs the 3.27.
As fatigue is such a common failure with a GT6 diff it really isn't worthwhile fitting a secondhand one - even assuming you can find anything. Recon is by far the best way to go - just make sure it comes from Canley Classics.

AJLintern

4,206 posts

264 months

Monday 7th August 2006
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I've read on the Club Triumph forum that you need to be careful with some 'reconditioned' diffs. Apparently there should be about 8-10 degrees of backlash, otherwise the gears are meshing too tightly, which will actually cause it to whine and wear out quicker. You should be able to easily turn it by hand.

slammedvanman

167 posts

215 months

Saturday 14th October 2006
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arh - we could form a club as I've now broken mine on the GT6 (yesterday, Friday the 13th. Knew i should have stayed indoors).

Does anyone have any experience of limited slip diffs for a Triumph? I've just been looking at the Quaife site & they appear to be priced @ £460. This is about the same as a standard reconditioned unit (with new crown & pinion) from some of the regular Triumph suppliers? Seems to good to be true? Is the Quaife price purely for the internals? Would you then need to install the internals in a regular diff case?

yertis

18,090 posts

267 months

Saturday 14th October 2006
quotequote all
slammedvanman said:
arh - we could form a club as I've now broken mine on the GT6 (yesterday, Friday the 13th. Knew i should have stayed indoors).

Does anyone have any experience of limited slip diffs for a Triumph? I've just been looking at the Quaife site & they appear to be priced @ £460. This is about the same as a standard reconditioned unit (with new crown & pinion) from some of the regular Triumph suppliers? Seems to good to be true? Is the Quaife price purely for the internals? Would you then need to install the internals in a regular diff case?

As far as I can recall (I broke a TR6 diff last year) the Quaife price is just for the gubbins inside.

arh

Original Poster:

1,222 posts

240 months

Sunday 15th October 2006
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I bought a second hand spitfire diff in the end, just as an experiment to see if it made much difference having a different ratio. It is working fine, cost £50 and means 300 rpm less at 70 mph with no noticable loss of acceleration.

slammedvanman

167 posts

215 months

Wednesday 18th October 2006
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arh said:
I bought a second hand spitfire diff in the end, just as an experiment to see if it made much difference having a different ratio. It is working fine, cost £50 and means 300 rpm less at 70 mph with no noticable loss of acceleration.



I considered second hand but don't want to have to do the job twice so think I'm going to bite the bullet. I spoke to Quaife, the LSD is exactly that, the diff part to which you need to add the crown & pinion (as I suspect I've lost a tooth) @ about £150. That's £610 in parts alone without getting someone to re-build it. Canley Classics offer a fully re-conditioned unit (new crown & pinion) for £350 so I will probably go for that

yertis

18,090 posts

267 months

Wednesday 18th October 2006
quotequote all
slammedvanman said:
arh said:
I bought a second hand spitfire diff in the end, just as an experiment to see if it made much difference having a different ratio. It is working fine, cost £50 and means 300 rpm less at 70 mph with no noticable loss of acceleration.



I considered second hand but don't want to have to do the job twice so think I'm going to bite the bullet. I spoke to Quaife, the LSD is exactly that, the diff part to which you need to add the crown & pinion (as I suspect I've lost a tooth) @ about £150. That's £610 in parts alone without getting someone to re-build it. Canley Classics offer a fully re-conditioned unit (new crown & pinion) for £350 so I will probably go for that



I was about to say it's an easy job (changing the diff) but tehen I remembered that while it is on a TR6, it isn't so in a Spit/GT6, what with springs and douughnuts etc.

tr3a

507 posts

228 months

Wednesday 18th October 2006
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yertis said:
I was about to say it's an easy job (changing the diff) but tehen I remembered that while it is on a TR6, it isn't so in a Spit/GT6, what with springs and douughnuts etc.

No Spit ever had doughnuts and not all GT6's have. Exchanging the transverse spring is a doddle on both. Although I've never worked on a TR6, I imagine changing the diff on a Spit/GT6 won't be much harder than on a TR6 - perhaps even easier.

slammedvanman

167 posts

215 months

Thursday 19th October 2006
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Only the rotoflex 6's have the doughnuts. Mine's a non-rotoflex mk3 so should be pretty straight forward (famous last words). I only changed the driveshafts 4 months ago so am reasonably familiar with where to start. It's just a problem of finding the time now. irked

yertis

18,090 posts

267 months

Thursday 19th October 2006
quotequote all
tr3a said:
yertis said:
I was about to say it's an easy job (changing the diff) but tehen I remembered that while it is on a TR6, it isn't so in a Spit/GT6, what with springs and douughnuts etc.

No Spit ever had doughnuts and not all GT6's have. Exchanging the transverse spring is a doddle on both. Although I've never worked on a TR6, I imagine changing the diff on a Spit/GT6 won't be much harder than on a TR6 - perhaps even easier.


No I know that about Spits (ref doughnuts) but I couldn't remember which we were talking about. The point about the transverse sping is that IIRC it is bolted to the top of the diff, so you need to fiddle around with that side of things as well as the diff mounts and drive shafts. Also the diff hangs on some very long studs - helps greatly to have a deep socket to undo the nylocs.

All this GT6 / Spit talk makes me want another one.

slammedvanman

167 posts

215 months

Thursday 19th October 2006
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Wanna buy one with a busted diff

ARH

Original Poster:

1,222 posts

240 months

Friday 20th October 2006
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3 to 4 hours has a diff changed if you only have axle stands. I guess it would be quicker with a decent lift. The spring mounting on the top of the diff is easy to undo, not so easy to refit.