T56 to replace 5 speed

[Erik the Awful]

I dunno, it was pretty nice having an auto when towing a race car through Houston or Atlanta rush hour traffic. Of course, the real MVP was the Cummins with good trailer brakes also being a contender.

 

[letitsnow]

I bet it was. I would plan so that I didn't have to be there during rush hour, and would be rowing gears. Or using a gas motor, with 4l80...

 

[Supercharged111]

The 5 speed in an 88 is even weaker than the nv3500 which is only rated to 300tq. It also doesn't shift fast. The T56 is a great tranny in the LS T56 version, not so much in the easier to adapt to a Gen 1 small/big block LT T56 version. The LT version uses an odd pull style clutch that severely limits your choices and they are all expensive. There is also something about a different starter (some V6 starter comes to mind). The T56 is a much more performance oriented tranny and it shifts good quickly.

As far as putting one in; the shifter sits about 6 inches further back, it fits in the tranny tunnel well, you have to move the cross member back, your master will work but you may be able to use your stock hydraulic line and if replacing a nv3500 then the drive shaft works.

As with anything there are upgrades. There is the T56 magnum, different gear ratios, stronger internals, a mid shift conversion to bring the shifter up through the original hole, speed bleeders... the list goes on.

Myself I would do an entire set up out of an LS powered F body, get a light weight flywheel, LS7 dual clutch, upgraded master and slave (probably Tick), remote speed bleeder and a good short throw shifter. In other words, I'd probably throw 4-5k at it.

A couple points to clarify here. The early LT trannies came with paper lined brass syncros but somewhere around 95-96 they went to carbon syncros. Carbon syncros are a direct fit for the older style. All F body boxes had double cone 1-2 and single cone on the rest. You can use a carbon 5-6 syncro on reverse as they're all the same. The biggest difference is the clutch type like Skylark pointed out, but the LS7 is not a "dual". The factory flywheel is a dual mass unit which is one of the reasons why you want to throw it in the trash and replace it with a lighter piece. The LS7 stuff is big and heavy in stock form. The later LT1 clutches were twin disc units and there are flywheels out there that will let you run them on an LS type of setup. If you want to run an LS type trans on an older GenI SBC, there is an adapter of some sort that will be necessary. I'm not sure if it's just a flywheel spacer or what but the bells are deeper on an LS. The other thing you'll have to do when setting up the clutch is measure for a slave cylinder shim. If you don't get that dead nuts, you WILL have shifting issues. The Tick master is an absolute necessity. If you can run the Camaro slave vs the Corvette, go for it as that only had 1 orifice vs the Corvette's 3. On the contrary, the older LT style factory hydraulics have been flawless for me since I got my Camaro back in 2013. My Corvette sent me down the rabbit hole and in the meantime I ended up hurting 2nd gear so I get to rip it all down and fix that now on top of everything else I'd already done trying to get it to shift right.
A note about the T56 Magnum, it's actually a TR6060 but in a case that allows it to be bolted where a T56 once lived so it's not really a T56 at all.

 

[ccreddell]

Like SC111 says, the bell housing doesn’t work with the LS T56 and a SBC. I don’t remember who makes the swap BH, but it’s one of the major tranny shops. I think it might be McLeod. Anyway, it allows you to bolt it to a SBC and run a normal clutch. Keep in mind that you’re gonna want to run a 4.56 or better gear to compensate for the greater weight of the truck and most likely a taller tire. And there’s no reason you can’t tow with a T56. It’s a function of its ability to withstand the torque-it doesn’t know whether you’re towing something behind it or putting a 800 hp turbo motor in front of it. If you know how to tow, you won’t hurt it.

 

[Supercharged111]

Like SC111 says, the bell housing doesn’t work with the LS T56 and a SBC. I don’t remember who makes the swap BH, but it’s one of the major tranny shops. I think it might be McLeod. Anyway, it allows you to bolt it to a SBC and run a normal clutch. Keep in mind that you’re gonna want to run a 4.56 or better gear to compensate for the greater weight of the truck and most likely a taller tire. And there’s no reason you can’t tow with a T56. It’s a function of its ability to withstand the torque-it doesn’t know whether you’re towing something behind it or putting a 800 hp turbo motor in front of it. If you know how to tow, you won’t hurt it.

If you do tow with it, I'd stay out of 6th. The 5/6 driven gear is only splined under 5th, 6th was never meant to be torqued on very hard. It was either Ford, Dodge, or both who splined the whole thing but GM did not. Of course you could shove a G Force custom 5/6 gearset in there as well to fix all that.

 

[ccreddell]

Yeah, I forgot about that-then again, I cant see being able to tow a heavy load in 6th....

 

[nobears]

The only thing I plan to tow/haul with this truck is ass.