LS1 Supra Swap

[Quin]

Sorry to read that you are looking for a t-56. I have one in my Cadillac V and if you ask me it is the worst transmission in the world. It is a very sloppy tranny, and have had in the shop more times I can count on one hand

Musta just had a bad stretch of luck. Most people don't have too much trouble with them. My uncle has one in his 03 Cobra, just upgraded to a Liberty 26 spline input shaft (factory Fords are 10). He's making ~550rwhp on blower and we're in the middle of putting a 125 shot on it right now, no issues so far.

Are you still using the stock shifter?

 

[7Mboost]

Sorry to read that you are looking for a t-56. I have one in my Cadillac V and if you ask me it is the worst transmission in the world. It is a very sloppy tranny, and have had in the shop more times I can count on one hand

Wow I have only heard of one other complaint about the T56 transmission before this, what's been the problem with yours? I've heard the LS2 T56 GTO's had some sort of changes that had issues (with flat-foot shifting).

Back on topic, I'll be watching this build, LSx engines are pretty much THE engine swap to do in the import world at this point bang for buck wise.

 

[speedgilligan]

Ive heard mixed opinions on the T-56. Most people love it, but I guess its kinda the love we give our R-154's....Love-Hate lol. My friends LS2 Goat has only 30K on it and needed the T-56 replaced. But I know others say they are one of the best Borg-Warner did. Depends on what you get.

 

[Greg55_99]

You need one of these jewells to keep the R154.. :naughty:

Greg

 

[limequat]

^ Would really keep the costs of the swap down. Between sourcing the trans and driveshaft, you'll probably be out 2 grand. Not to mention ancilliaries like: clutch, speedo drive, trans mount.

I'd make every effort to keep the stock R154. Either that or get a cheap AR5 + the adapter.

 

[Shatonapples]

The gear ratios would never work on an LS1 with the rear end gears and the R154 on the supra. I'm hoping to actually get some gas mileage out of this LS1, so I'm hoping to spin lower RPMs like 2500 or something less than the 3200-3500 RPMS that the supra runs on the highway.

I personally dislike the feel of the R-154, but I guess that's probably because I still have the stock shifter on it. I have a friend who wants the motor out of another camaro that has an LS1 and T56, but he doesn't want the tranny, he wants my 4L60E, so we might split the cost of that car and split the profits off parting it out.

 

[92nsx]

Musta just had a bad stretch of luck.

Are you still using the stock shifter?

Bad stretch of luck?!?!? head on over to cadillacforums or LS1tech and read all about the bad ones out there. Maybe a bad stretch of t56's from 2004-2007 in the caddys, I dont think so. It is just a sloppy tranny, & sloppy = excessive/premature ware.

BTW the caddy goes BACK in on Monday morning, this time there going to try a new t-56 and see how long this one lasts, lol. I dont give it much time before it also fails.

Also talk to a rebuild shop that has first hand rebuilding them and Im sure they will tell you the same thing. Put it this way 6th gear alone has .047" play and LOTS of "quirks" to the t56 That is no where near a "tight transmission".

OEM shifter, yes correct, the car is 100% OEM, no modification needed with 400 hp and a being a DD

Wow I have only heard of one other complaint about the T56 transmission before this, what's been the problem with yours? I've heard the LS2 T56 GTO's had some sort of changes that had issues (with flat-foot shifting).

Jumping out of reverse. then jumping out of reverse and 1st. Grinding going into reverse. Then 6th gear not engaging in %100. causing it to jump out, not go in, or just grind and grind then go in (up coming this will be the third time now its going in for this). Im sure the shop is sick of seeing my caddy by now, but I wont back down till it is working correct.

BTW I love the my R154 once warmed up

 

[IJ.]

LOTS of sad T56's here in Australia, don't know if anyone remembers but I did a trial fit with a T56 and decided against it for a few reasons way back.

Ended up buying a new TKO-500 instead.

 

[limequat]

The gear ratios would never work on an LS1 with the rear end gears and the R154 on the supra. I'm hoping to actually get some gas mileage out of this LS1, so I'm hoping to spin lower RPMs like 2500 or something less than the 3200-3500 RPMS that the supra runs on the highway.

"Never work"?
Ok, maybe the ratio spread isn't as wide as a T56, but that's a long way off from saying it would never work. I think the R154 and 3.73 gears would be just fine.
I can understand you wanting the tall 6th gear though.

 

[Bigzavs]

The gear ratios would never work on an LS1 with the rear end gears and the R154 on the supra. I'm hoping to actually get some gas mileage out of this LS1, so I'm hoping to spin lower RPMs like 2500 or something less than the 3200-3500 RPMS that the supra runs on the highway.

not sure where you got that info from, but its not right at all. I used to have a firehawk and i ran 3.42's, 3.73's, and 4.11's in it with a T56.

on the highway about 70mph

3.42's were about 1900
3.73's were near 2300
4.11's were around 2700

like limequat said, T56 with the 89+ 3.73 rear would be a great combo. it was def my fav of the gearing.

 

[limequat]

LOTS of sad T56's here in Australia, don't know if anyone remembers but I did a trial fit with a T56 and decided against it for a few reasons way back.

Ended up buying a new TKO-500 instead.

Is that the trans de jour for the Holdens?

 

[IJ.]

Is that the trans de jour for the Holdens?

T56 was now they're onto the 6060 and they're still not happy

 

[Shatonapples]

not sure where you got that info from, but its not right at all. I used to have a firehawk and i ran 3.42's, 3.73's, and 4.11's in it with a T56.

on the highway about 70mph

3.42's were about 1900
3.73's were near 2300
4.11's were around 2700

like limequat said, T56 with the 89+ 3.73 rear would be a great combo. it was def my fav of the gearing.

Not sure what info you're saying is incorrect, I was just guesstimating the RPMs that I would be getting. But the RPMS I got with the supra tranny and rear end were terrible. I mean, yeah, it was hella fast on the highway, but I don't need high RPMs to be fast on the highway with the LS1.

I mean, I guess if the T56s are as bad as all of you are saying, it would be better to go with the R154, but does anyone know why they're bad?

 

[Bigzavs]

Not sure what info you're saying is incorrect, I was just guesstimating the RPMs that I would be getting. But the RPMS I got with the supra tranny and rear end were terrible. I mean, yeah, it was hella fast on the highway, but I don't need high RPMs to be fast on the highway with the LS1.

I mean, I guess if the T56s are as bad as all of you are saying, it would be better to go with the R154, but does anyone know why they're bad?

its my bad, i misread what you posted, didnt see you were talking about the R154.

the T56 is a good trans, just not the strongest in stock form (stock depending on what platform it comes from) if you got a T56, get it built to viper specs and you have a damn near indestructable trans. friend of mine ran 1700hp through the stock trans in his TT Viper

 

[Greg55_99]

This would just be TOO easy....

Greg

 

[limequat]

This would just be TOO easy....

Greg

Advance adapter? Also almost $500 last I checked!

 

[Shatonapples]

This would just be TOO easy....

Greg

Unfortunately, I'm not sure what I'm looking at. I'm down for other options, but a T56 seems like the best route to me so far. Getting one built to viper specs seems a bit expensive, any links to a parts kit for that so I can get an idea of how much that would cost?

 

[speedgilligan]

i dont know about the quality of these, but there are a few T-56's going around most of the time on the mustang forum corral.net. Ive heard the ones from mustangs are pretty well built

 

[IJ.]

i dont know about the quality of these, but there are a few T-56's going around most of the time on the mustang forum corral.net. Ive heard the ones from mustangs are pretty well built

From memory they're a different length/spline count input shaft to the GM trans.

 

[Shatonapples]

From memory they're a different length/spline count input shaft to the GM trans.

Hmmm, I didn't know that, but it wouldn't surprise me. At the very least, the bellhousings are different.