Used T56 - what to look for?

sambo · #1 (**permalink**) 10-04-2007, 07:25 PM

I'm weighing up whether to go new or used for the 6spd in my Cobra. New will set me back about $4500 with clutch, pressure plate, shifter, bellhousing. Going second hand I have a quote for $2750 for all that out of a VT (gen 3), having reportedly done 87,000 km.

I plan to put the T56 behind a 6.0L L76 with moderate upgrades but nothing wild.

Are there any weak spots with these gearboxes? Anything that was fixed in later versions? Signs of abuse or heavy wear and tear? Any other considerations, particular versions to avoid or look out for?

Thanks

alffie · #2 (**permalink**) 10-04-2007, 08:29 PM

I prefer new as I dont want to have to pull the trans out in 6 months time. Cant tell anything with it on the floor, If you can drive it make sure the shifts are good. The syncros are the weak point of the T56. Get on to Mal wood auto web site he is the Tremec dealer, he has all the ratios that you can get for the T56 on there.

Aussie Mike · #3 (**permalink**) 10-04-2007, 08:49 PM

They didn't change much from when they were made by Borg Warner to brand new ones. I've stripped and built early ones (the one in my car was a prototype built for Holden) and brand new boxes still in the crate.

It's going to be hard to tell what sort of condition it's in unless you can drive it or strip it to see what it's like inside. even pulling the sump plug and looking for filings isn't going to tell you much because there are 2 big magnets in the bottom of the box that catch everything.

1st and 2nd synchros are triple cone design with carbon blocker rings so they work pretty well. The gears are all about an inch wide and very beefy. I've not seen any real dammage to them but the teeth on the synchro hubs get rounded and they can be hard to shift.

The weak link is the 3rd-4th synchros ans they are only single cone design. Corvette transaxle varieties got triple cone 3rd-4th but there's no easy way to swap them into the Holden boxes. The keys on the synhcro hubs shear off when shifting hard with big HP as they are only pressed steel. This causes the box to lock in gear. I replace them with billet steel keys I bring in from the US. I also ususally replace the aluminium 3-4 shift fork with the steel unit designed for the viper T-56 as it's a much stronger piece and wont flex under hard shifts.

Here's the keys out of Garretts box after I broke it at Shelbyfest last year

Cheers

sambo · #4 (**permalink**) 10-04-2007, 09:00 PM

Mike, thanks for the info once again. Garrett has that turbo LS1 monster, right? I reckon a mildly worked L76 will be fine with the stock box, given that I treat it right. How do you think the Holden clutch/flywheel will hold up with some track work and say 300kw?

What are the stronger keys worth and how many hours to replace?

Alffie, yes I have spoken to Mal Wood and got a quote as follows: "a very low k T56 and rebuilding it to the Cobra specifications with the close ratio 5th and 6th gears and the centre shift. The price is $4585 inc GST and it is supplied with a bellhousing and a CSC". Not bad in my opinion.

Tenrocca · #5 (**permalink**) 10-04-2007, 09:02 PM

Sambo - Call Mark at BBW spares (Barry Burke spares) at Waragul - $2500 brand new (no clutch). He has one left (after mine). (03) 5622 0000.

sambo · #6 (**permalink**) 10-04-2007, 09:05 PM

Tenrocca - thanks mate. Is that the one on eBay? I was just looking at it!

Tenrocca · #7 (**permalink**) 10-04-2007, 09:21 PM

Yup - I got that one but suspected you might be interested in one as well, so checked if he had another for ya. At that price even without clutch I dont think Id muck around with an unknown 2nd hander.

sambo · #8 (**permalink**) 10-04-2007, 09:55 PM

That's right - and much appreciated, thanks. I spoke to Mark and they're advertising it tonight if they don't hear back from me. I rang the guys who quoted me the whole engine/gearbox shooting match and he said at $2500 there's only about $90 profit - not much for a big ticket item. So you've done very well.