TREMEC T56 Magnum S197 Transmission

Juice

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I literally just picked mine an hours ago up from JPC Racing. I got the 2.97 ratio and combined it with 4.10 rear gears. RSt clutch with 450 RWHP.

Definitely noisy and mechanical in feel. As I drove it, I could feel it break in, though shift effort is not really easy no matter what giving the nature of the trans. Looking forward to spring to run that paces ...
Not sure why you have shit effort issues, mine shifts super easy at any rpm. No real NVH complaint either. I went with the close ratio (2.97 1st) for open tracking/road course use.
 

1950StangJump$

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Not sure why you have shit effort issues, mine shifts super easy at any rpm. No real NVH complaint either. I went with the close ratio (2.97 1st) for open tracking/road course use.

I didn’t say I had shift effort “issues” - at least not what I was trying to say. I said there is an obvious mechanical feel .... not that there was something wrong with it
 

Norm Peterson

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Definitely noisy and mechanical in feel. As I drove it, I could feel it break in, though shift effort is not really easy no matter what giving the nature of the trans. Looking forward to spring to run that paces ...
A slightly longer shift lever will definitely help with the shift effort as well as reduce any notchiness.

Having the shifter bolted directly to the extension housing will allow more noise and vibration to sneak through. Insulating the shift lever itself makes a very noticeable difference. The picture below was for a MGW that I also lengthened the lever for.

full


It was only going to be a temporary test, so it's made of stuff I had around the house - I think it's foam hot water piping insulation and duct tape that's pretty close to the rest of the interior grey color. But the difference was big enough that I ended up leaving it there.


Norm
 

1950StangJump$

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Thanks! I am okay with it. I wasn’t trying to complain about effort, just noting the “direct” feel.
 

2010GlassGT

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Another clutch for me, another problem. I have six months and 3,500 miles on this new McLeod single disc. Now the transmission is grinding/whining when upshifting. The shifter moves through the gate and into gear fine, but now I have grinding during and after the shift is completed. I actually pumped the clutch pedal on a 4th gear shift and the noise got worse as I did so. About ready to sell the car. Will be taking to the transmission shop and most likely have the clutch, flywheel, and slave all replaced. I'm at a complete loss and my three years of ownership has been constant problems. I love the car when it has no problems, but that's far and few between. Any ideas for round #3?
 

1950StangJump$

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Another clutch for me, another problem. I have six months and 3,500 miles on this new McLeod single disc. Now the transmission is grinding/whining when upshifting. The shifter moves through the gate and into gear fine, but now I have grinding during and after the shift is completed. I actually pumped the clutch pedal on a 4th gear shift and the noise got worse as I did so. About ready to sell the car. Will be taking to the transmission shop and most likely have the clutch, flywheel, and slave all replaced. I'm at a complete loss and my three years of ownership has been constant problems. I love the car when it has no problems, but that's far and few between. Any ideas for round #3?

Consider a twin disk McLeod like the RST. Got to RXT if you are pushing big power.

The twin disks make a shit ton of noise . . . you get the "marbles in a coffee can" in 4th and 3rd between 1600 and 1900 RPMs. But, that is to be expected, and the engagement and feel are outstanding. Clutch disengagement/engagement is smooth and right at the top of the pedal for me.
 

2010GlassGT

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Consider a twin disk McLeod like the RST. Got to RXT if you are pushing big power.

The twin disks make a shit ton of noise . . . you get the "marbles in a coffee can" in 4th and 3rd between 1600 and 1900 RPMs. But, that is to be expected, and the engagement and feel are outstanding. Clutch disengagement/engagement is smooth and right at the top of the pedal for me.

Thanks for the suggestion. I actually started with a RST when I swapped to the Magnum. First one lasted 7K miles before locking up. McLeod rebuilt it and that one only lasted 5K. Then I swapped to the single disc (still with matching steel McLeod flywheel) to try and fix the problem. I will never use another McLeod in my life.
 

DiMora

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Thanks for the suggestion. I actually started with a RST when I swapped to the Magnum. First one lasted 7K miles before locking up. McLeod rebuilt it and that one only lasted 5K. Then I swapped to the single disc (still with matching steel McLeod flywheel) to try and fix the problem. I will never use another McLeod in my life.

Were you using a McLeod flywheel? You cannot use a factory flywheel with McLeods despite what they say to the contrary.
 

2010GlassGT

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Were you using a McLeod flywheel? You cannot use a factory flywheel with McLeods despite what they say to the contrary.

Yes, I've been using a McLeod lightened steel flywheel for the past 15K miles, all three times.
 

hoyabob2003

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Sorry to hear about your issues. I'm running an RXT with the lightened flywheel. No issues at all. I've had quite a few cars over the years and to be honest, this divine setup shifts with better, more precise feel than my Boxster-S. No joke. Tremec knocked it out of the park with this one.
 

1950StangJump$

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I messaged a couple of you, but for the general audience . . . anyone ever figure out why the cruise control works in 4th and 6th but not 5th for the 05-09s with the Magnum swap?
 

Midlife Crises

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Interesting. My cruse does not work in 5th either. First I heard someone else mention it. I installed a T56 Mag XL kit from SST as part of my winter upgrade to a 2010 GT. The kit really did bolt right in with the provided bell house, crossmember and one piece driveshaft. I installed a McLeod lightened steel flywheel and single disc clutch set with a stock slave cylinder and it works great. Speedo and backup lights plugged in also. Just think it’s odd the cruse won’t work in 5th.
 

1950StangJump$

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Interesting. My cruse does not work in 5th either. First I heard someone else mention it. I installed a T56 Mag XL kit from SST as part of my winter upgrade to a 2010 GT. The kit really did bolt right in with the provided bell house, crossmember and one piece driveshaft. I installed a McLeod lightened steel flywheel and single disc clutch set with a stock slave cylinder and it works great. Speedo and backup lights plugged in also. Just think it’s odd the cruse won’t work in 5th.

As others have said, I assume that there is something in the tune, when up against the near gear set, that the computer doesn't like. Mine is a 2008 with the 2.97 first and 4.10 gears. McLeod steel flywheel and RST twin disk. I have cruise in 4th and 6th only . . . no other gears, e.g. 3rd, as some here have reported.

I had the same swap done on my 2011 years ago - my experience is buried in this thread somewhere. At first, I had zero cruise control with a VMP tune. The 2011+ are obviously way different from a speedo and computer standpoint.

VMP sent me a revision, and I had cruise in 6th only from that point.
 

Norm Peterson

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Interesting. My cruse does not work in 5th either. First I heard someone else mention it. I installed a T56 Mag XL kit from SST as part of my winter upgrade to a 2010 GT. The kit really did bolt right in with the provided bell house, crossmember and one piece driveshaft. I installed a McLeod lightened steel flywheel and single disc clutch set with a stock slave cylinder and it works great. Speedo and backup lights plugged in also. Just think it’s odd the cruse won’t work in 5th.
Overall that's very encouraging as I'm planning a very similar swap for my '08 GT. And I do appreciate the heads-up on the CC issue even though I'm unlikely to ever run into it myself.

Think I'll be sticking with stock-weight flywheel though (3.73's with the 2.66 low Magnum XL, street/road course/no drag racing or sprints from a standing start "in Mexico")


Thanks to both you and 1950.


Norm
 

Racer47

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There is a transmission gear ratio table somewhere in the tune file that needs to be updated for the 6 speed. Cruise control in 4th gear works because both the 5 spd and 6 spd are 1:1 in 4th.

6th gear works because its close enough to the original stock 5th gear, 0.63 vs 0.68. The computer thinks the car is in 5th.

5th gear on the 6 spd won't work because the computer does not recognize it as a valid gear ratio.
 

fdjizm

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Were you using a McLeod flywheel? You cannot use a factory flywheel with McLeods despite what they say to the contrary.

Hmm why not? I am waiting on installing a mcleod super street pro clutch with an exedy lightweight steel flywheel. Aren't the aftermarket flywheels just copies of the factory spec why would the mcleod need a specific flywheel?
 

Norm Peterson

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There is a transmission gear ratio table somewhere in the tune file that needs to be updated for the 6 speed. Cruise control in 4th gear works because both the 5 spd and 6 spd are 1:1 in 4th.

6th gear works because its close enough to the original stock 5th gear, 0.63 vs 0.68. The computer thinks the car is in 5th.

5th gear on the 6 spd won't work because the computer does not recognize it as a valid gear ratio.
Makes sense.

I'm assuming that the computer is comparing engine rpms against transmission output shaft rpms (speedometer connection), and comparing that against a gear ratio table. I wouldn't be too surprised if 2nd gear with the 2.66 1st Magnum caused the same problem. I'm only guessing here, don't ever use CC myself.


Norm
 

DiMora

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Hmm why not? I am waiting on installing a mcleod super street pro clutch with an exedy lightweight steel flywheel. Aren't the aftermarket flywheels just copies of the factory spec why would the mcleod need a specific flywheel?

No; the McLeod clutch friction disc surfaces do NOT line up with an OEM flywheel's surface...whereas the McLeod flywheel is a PERFECT match to their clutch. If the Surfaces do not mate perfectly, the flywheel will cut a groove into the friction material on the clutch surface and then as the clutch gets hot, the clutch will hang up and fail to release. (Clutch material will swell and lock into the worn groove in the flywheel)

The bottom line is a use a McLeod flywheel with a McLeod clutch if you don't want to think about it - or if using another brand flywheel, make SURE the surfaces mate correctly or you will be tearing the tranny out to replace the clutch again very soon.
 

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