Manual Transmission T56 | T5 | MN12 | Clutches | Hydraulics | Shifters

T56 replacement options

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Old Oct 28, 2008 | 04:21 PM
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Default T56 replacement options

I'm looking at different options for replacing the T56 in my '99 Z28. I've seen that the LT1 cars have different input shafts, the Mustang T56's have different gear ratios, and the LS1 GTO cars swap in with no problems. What about the LS2 equipped GTO's? Do the LS2 cars have different gear ratios or input shafts?
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Old Oct 28, 2008 | 04:39 PM
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You say you're replacing the transmission in your Z28 - why? Have you looked at having your T56 rebuilt? We offer this service with very competitive pricing:

http://www.tickshift.com

That said, if you're looking at replacing the transmission with a GTO unit, the input shafts are the same, but the gear ratios are different.

Your transmission is geared like so: 2.66:1 1.78:1 1.30:1 1.00:1 0.74:1 0.50:1
The GTO Transmission (M12) is geared like so: 2.97:1 2.07:1 1.43:1 1.00:1 0.84:1 0.57:1

The GTO transmission also use triple cone synchronizers, making them more desireable but also more expensive to rebuild.

Good luck!

Last edited by Joey@Tick; Oct 28, 2008 at 04:50 PM.
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Old Oct 28, 2008 | 04:44 PM
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I screwed something up in my rebuild and tore up reverse gear, a couple bearings, the mainshaft and some other pieces. See my post, HELP broke something in T56.
I was positive I had 2.66 first gear and .50 6th gear. I have a LS1 camaro, not an LT1 camaro.
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Old Oct 28, 2008 | 04:51 PM
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Originally Posted by bb5401000
I screwed something up in my rebuild and tore up reverse gear, a couple bearings, the mainshaft and some other pieces. See my post, HELP broke something in T56.
I was positive I had 2.66 first gear and .50 6th gear. I have a LS1 camaro, not an LT1 camaro.
Doh - - Fixed.

For the cost to replace all of those pieces, you may be better off finding a whole replacement. Look for a GTO unit if you can find one reasonably priced.
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Old Oct 28, 2008 | 04:58 PM
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Besides the gearing differences, would I have to swap input shafts and/or clutches, driveshaft yoke, bellhousing, or anything else to get a LS2 transmission to bolt to my LS1 engine? How about different clutch slaves?
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Old Oct 28, 2008 | 06:25 PM
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If the GTO unit has the F body shift selector on it , its a direct replacement . Its gear ratio is a little lower than the F body . Some people like it , others don't . I am actually building myself a non Cobra Ford T56 for my 1994 Gt with a 393W . I changed the gear ratio from the factory 2.97 to the F body 2.66 ratio its stronger and better suited for the power my car will be making .

The biggest advantage to the GTO unit IMO , is the syncro design . Its like the Vettes and rarely gives problems . I work on 10 times the F body units that I do the Vette or GTO .
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Old Oct 28, 2008 | 06:33 PM
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Thanks source, I appreciate the help.
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Old Oct 28, 2008 | 06:43 PM
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Not a problem .
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Old Oct 28, 2008 | 08:15 PM
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Originally Posted by thesource

The biggest advantage to the GTO unit IMO , is the syncro design . Its like the Vettes and rarely gives problems . I work on 10 times the F body units that I do the Vette or GTO .
And since you need a new mainshaft, you can pickup a replacement GTO mainshaft, a used C5 T56, and have yourself a nice GTO-like T56 at about the same price of a rebuild, or 1/2 price of a replacement trans.

mike
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Old Oct 29, 2008 | 08:19 AM
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How about a trans from a Cadillac CTS-V? They had the LS6 engine. They look to be cheaper used than the GTO transmissions. I haven't found any pictures of them but I heard they have a different output shaft.
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Old Oct 29, 2008 | 08:27 AM
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Totally different main shaft and tail housing .
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Old Oct 29, 2008 | 09:42 AM
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Originally Posted by bb5401000
How about a trans from a Cadillac CTS-V? They had the LS6 engine. They look to be cheaper used than the GTO transmissions. I haven't found any pictures of them but I heard they have a different output shaft.
They can be used as a donor to rebuild your LS1 T56 with a GTO mainshaft, but can't be used directly without changing your shift linkage, driveshaft, crossmember, sensor connectors, etc.
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Old Oct 29, 2008 | 01:55 PM
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I found pictures of the CTS-V transmission. It looks like I could swap my mainshaft (if I had a good one), extension housing, shifter and possibly shift rail over to the Caddy trans and it would work. Any other things I would have to swap or will this not work? The reason I ask is because I'm finding CTS-V engine/transmission combos for much less than GTO engine combos. It would be sweet to score an LS6 with low miles for my Camaro. If I'm just wasting my time then I can get all the parts to fix my transmission for about $900. I have to make a decision by the end of this week. The wife is driving my truck, I'm driving the Chevelle (8 mpg!) so it'd be nice to have my fuel efficient Z28 back on the road.
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Old Oct 29, 2008 | 03:00 PM
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As mentioned, you need to use a GTO mainshaft to make it work, along with most of the shiftrails, housings, etc. from your LS1. Not for the faint of heart though, if you had trouble rebuilding the LS1 T56, the CTS-V/GTO will be as hard if not harder to deal with, in addition to all the conversion issues.
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Old Oct 29, 2008 | 03:29 PM
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I didn't have trouble rebuilding it, I had trouble making it live! Sounds interesting, even fun. I just wish I knew what I did wrong on the previous build. The only thing I can figure is I didn't reshim it and the bearings were too tight. I just put it together and checked if it would go into all gears. It did, so I installed it. If I could figure out how to post the pictures to my posts you all could all see if I installed something wrong!
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Old Oct 30, 2008 | 10:24 AM
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I uploaded photos to photobucket. The URL is: http://s415.photobucket.com/albums/pp238/bb5401000/
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