88Greg

My 3rd gen has one of these in it. These were sold in the early 90's from BorgWarner for retrofitting into 3rd gen f bodies etc. They have a thick steel adapter plate on the front that allows it to bolt to an old-style GM bellhousing (like T5) and use an old style clutch and linkage etc. Its from 1994 era; way before LS T56's came out, And it has a diff shifter location than a 4th Gen T56, also has mech speedo drive provision.
The trans feels like it could use a freshen up. Also I am LS swapping the car and wondering if the trans can be adapted (sorta like an LT1 trans can be) But I can find NO info on these as far as what parts they use.
Anyone got any info ? Thx.

jmd

iTrader: (4)

They are pretty straight forward. They're a 93 Fbody box mostly, with exterior changes (existing castings with different machining) and long maindrive (input.) It is not an input and front plate change-over to being LS compatible.

The easy answer is find the right buyer, go for a T56 Magnum, shorten your driveshaft, and figure out the crossmember so it will work and mount the torque arm.

If you were local I would talk to you about a Stage 2 98-02 unit I have.

Twin_Turbo

iTrader: (25)

Anyone know the input shaft length on these?

Twin_Turbo

iTrader: (25)

apparently the Retro is 3/4" longer than the LS1



LT1 - LS1 - Retro - CTS-V

Twin_Turbo

iTrader: (25)

Ok, so the V8 T5 has a 6.5" input shaft, so with an SBC bellhousing this is the correct length.

The LS1 has about the same length, 6.46. IF the T56 would bolt to a SBC bellhousing it would be about the right side. However the adapter plate offered is about 3/4 thick. For the retrofit they must have used a 3/4 longer shaft, if you were to just buy the adapter plate and use an LS trans then you would need a 3/4 extended pilot bearing (which is often mentioned as being required)

So in order to drop my retrofit T56 behind my LS1 I have to grind the midplate for the hydro throwojut lines and use a spacer. ugh

If I want to use it on an SBC I'd have to use the adapter plate as the input is too long to use with my quicktime coversion bell (damn)

What to do now. I have 1 LS1 T56, 1 retrofit and 1 tr6060 (for my 495 lsx biut it's for an IRS and would need a telescopic driveshaft because it's set up for a drive donut)

jmd

iTrader: (4)

I think there is a scatter shield for the '10 Camaro (requires front plate too). If that's deeper, it may be the way to go; those inputs are long.

Otherwise, there's always 3 ways of doing everything.

peterc005

Why would the Retro T56 have a longer input shaft?

Was it to move the shifter towards the rear, or was it to reuse the T5 bell housing?

Surely a shorter input shaft would be stronger and have the potential for a small bell housing and better clearance?

MoJoe

iTrader: (5)

T5 bell is longer than the LT/T56 bell. Add the 1/2"-3/4" steel plate, and the input shaft has to be that much longer, too.

To reuse the T5 bell, and standard flywheel, clutch, and pressure plate.
And because the trans body is moved back, the aftermarket tail housing has to move the shifter forward to put it in the right place.

Supported from both ends (bushing/bearing in the crank), there likely isn't much difference in strength. It is more a matter of finding an easily available bell housing, flywheel, and pressure plate, and still fit a throwout bearing in between. (clutch thickness is more or less the same.)

jmd

iTrader: (4)

It was Borg Warner's way of making an aftermarket option. Compared to the production 93-97 boxes, the input is longer, the shifter is farther forward, and they gave it speedo cable drive. The net shifter location is pretty close to the third gen T5.

A shorter input shaft has zero strength advantage. It has possible negatives, all of which are minimal.

peterc005

Interesting information.

I'm thinking of swapping my T700 for a T56 and this gives me a better idea how it all fits together.

Did Borg Warner see many of these retrofit T56 units?

88Greg

Yep. This thing installs with the shifter coming up through the stock T5 tunnel boot (No hacking) and the stock speedo VSS sender drops right in. I wonder how many they sold. Not much info on net about them. There was also a Ford (mustang) version

jmd

iTrader: (4)

no idea if Tremec has Borg Warner production numbers; maybe.

the aftermarket is always smaller volume; they cast no new alum. for the a/m GM T56, only the input was unique.

there were at least two ford versions, one for the windsors, and the GM vers.

Twin_Turbo

iTrader: (25)

The complete rear section us different. Shortee relocated shifter stock mounting position and tq arm mount.

DAVEY420

That is so cool. I thought I remembered there being an aftermarket t56 but as the years went by I just thought everyone was using f-body, y-body, or viper trans back then. And it was so much tougher back then with no interwebs or anything. You had to figure it out. And even the aftermarket did things differently sometimes. I love reading about neat old stuff lol. Is the gearing the same as lt1 t56?

jmd

iTrader: (4)

Yes. 2.97 and 0.63.

I found an article I will try and scan in.

MoJoe

iTrader: (5)

That is the same as 93-stock only, and is rated at only 400 ft-lbs. 94-97 are 2.66 (1st) and 0.50 (6th), rated at 450ft-lbs. I assume 98-2002 (LS) are the same 2.66./0.50 with a longer input shaft due to PP/throwout changes.