Installed a Tremec Magnum XL in my S550

dodger789

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Took on a new project and thought I’d share it. Never thought I’d go this route but but just saying that doesn’t really surprise me.

Backstory: The car is a 16 PP so it has the 3:73 rear gears and is pretty heavily modified. Like most of us, I ran the MT82 with an MGW and had no real issue especially after adding that shifter. I didn’t break anything in my stock transmission and it worked the same from the day I bought till the day I took it out. For 28k miles I ran the stock clutch with it and I was fairly quick to add a Whipple and shortly after that E85. I was amazed at how well the stock clutch handled it. I do occasional road course days, and as some forum members can attest to from riding shotgun, I push the car hard and play with the line of limit. The 3:73 differential made 1st and 2nd gear pretty useless at my power level and considered changing diffs but didn’t want to ditch my Torsen. I don’t do 1/4 mile runs and for the most part I daily drive the car which includes commuting to work in traffic. The car is literally 95% street with casual manners and 5% track/canyon carving/hurt the feelings of another car brand/owner that unwisely has challenged.

I bring up this info because it has a factor in making choices in parts and gear selection. Also, my baseline is can my wife take the car out and drive it ‘normally’ without it being annoying/difficult to operate and that applies to me as well.

This is what I ended up buying and most of this comes in a kit which is the route I went:

Tremec Magnum XL transmission (duh)
First gear choice of 2.66 and opted for the 5th and 6th OD gears of the 2.97 trans which gives me in order of 1st to 6th, 2.66/1.78/1.30/1.00/.80/.63

Quick Time steel sfi bell housing

QA1 carbon fiber driveshaft with sfi (upgrade)

Bowler all-in-one harness for electronic connections

Rest of the kit included fluids, transmission mount, cross brace and mounting hardware

Also added the MGW shifter since I really appreciated what it did for the MT82


The clutch was a difficult and time consuming process and there is a endless amount of choices out there. Everyone has their preferred brand or special purpose for what their plans are for their car but this is also the reason I gave the back story above because it applies here. I would love to try all brands and models that I narrowed it down to (probably 5) but I’m not sponsored, a company that works in the industry nor someone with unlimited funds. My personal requirements were something near stock weight for stored energy, sprung hub and organic. I was open to single and dual disc setups knowing the inherent differences. Ultimately I went with the Ram Pro Series twin disc organic with steel flywheel.

Like I said, plenty of great choices to go with and I even tried for a short period, which was completely non cost effective for me, a Mantic 9000 organic series clutch which I will say was awesome with my MT82 the short time I had it. I could have easily just switched to 26 spline clutch discs but the light weight would have been an issue I feared so I did what I did.


Here’s some pics cuz that’s all most care about....

22B49E1B-D50F-436C-8D25-BF15FB08BE02.jpeg

6F75DE80-E680-4CFC-A1B1-79D7614C8285.jpeg
4EEB91A5-CB7B-46BF-AC05-FD2E63C79518.jpeg
5316F36B-7B02-4B19-85D2-746393F7A482.jpeg
28D8580D-70AB-4442-8B8B-6D04C3C7D196.jpeg
6D8013D6-5E5C-4CF1-B8EC-9732C8F707FB.jpeg
2A732B9A-D5B2-42D9-ADDD-71EAA031D3A8.jpeg
44345936-FA41-4B18-8A90-4EF865C8DB32.jpeg
FDF58B3C-984D-48CC-929C-8A8EC1A031B2.jpeg
48AC3E88-F9B9-4B38-BFFD-0125387C2188.jpeg
AF199552-9E96-4436-AB2F-DD5381D69DF9.jpeg
0E141C3E-4926-4F70-9BF8-C8BFF73D100A.jpeg
D755A471-DCA2-4C02-ABB4-32806973BAC0.jpeg
5178D562-26E9-4DBD-AA2F-D5730049969D.jpeg
8AA3B291-D17F-44E3-8577-D37B1B34F706.jpeg


At current writing, I’m around 300 miles on the break in. At first, and at around only 25 miles I thought I made a mistake with clutch choice. First gear start off from a stop had significant chatter but that has quickly become better and better and I’m sure will continue to get better as smooth slipping start off has become an easy thing to do now. Recently took the wife out to mess around with first gear in a parking lot and she did great but could notice the current difference. If you’re already moving, this clutch is just perfect. Clutch pedal effort is less than stock, initial grab and capture is well within the throw of the clutch pedal; not quick off the floor grab or late grab near the top. I’m 90% happier with the clutch than my first quick to judge impression.

I cannot say enough about the transmission. I absolutely LOVE the gears I chose granted I’m in the break in phase and not shifting over 4000 rpm for the most part but again, this is how the car will be driven most of the time. First and second gear are so much more useful and enjoyable to use. Fourth gear (1.30) in the MT82 was one of my most favorite gears to play in and also was a factor in choosing the magnum gear selection I did because third gear in this set is also 1.30 which made it perfect. 4th is now the 1:1 gear which I like and the two OD gears are gapped perfectly unlike our 5th to 6th is in the 15-17 MT82. I will say it is weird downshifting to 1st gear around corners in residential/commercial zones but it’s easy, called for and works like any other gear you’d be used to using normally. Hell, I’m still learning what gear to be in based on muscle memory of where the shifter used to be. I really couldn’t be happier with how this all works together and with the stock 3:73.

The driveshaft is awesome and the second QA1 I have owned and also part of the not a wise investment in regards to how long I had it in the car before switching to the Tremec. I’m sure it’s not the last time I’ll do that.

One other thing when I first got it on the road and getting a feel for it. There was a small vibration/drone in the car that came in around 3200 rpm and went out around 3800 rpm. Believe me I thought of every possible scenario and incorporated lots of others thoughts to the mix so before you start throwing out ideas, it was figured out. There is a reverse lockout solenoid that is on the drivers side tail section of the transmission and it was touching the body lightly. The idea of what to do was easy but the process of doing it wasn’t quite so easy especially without removing things. It took a small hydraulic ram to push, which happens to be a much stronger and stiffer section than I expected, the body panel away which now looks like this, totally fixed the issue and might as well be a mile away compared to what was before.

40801D28-C54B-49BF-A636-203E29CABFD4.jpeg


This is the electronic harness that was included with the kit and sold from Bowler. It incorporates all electrical connections and really made everything work easily and its adjustable for things such as tire size, OOS pulse calibration and reverse lockout parameters to make to your liking (speed at which lockout engages or deactivates). Reverse switch is a no brainer. Literally soldering 5 total wires to the original trans harness to make everything connect; the two reverse wires and reverse camera and light work like stock. Positive, ground and oss wire.....done. You download an app to your iPhone or android and and it Bluetooth connects when ever you want for changing parameters. Without going into too much detail, just go with it’s easy and works great. All connectors to the sensors on the trans are OE style and weather sealed.

429687FE-49C6-4C87-BA46-9CD49225392E.jpeg


In regards to the actual install, it’s no more difficult than changing a clutch if you’re comfortable with it. I really liked the separate bell housing.

That’s all I got for now. Still have miles to go before it all gets more aggressive testing but I have no doubts.
I have the same set up except I went with rxt clutch and 355 gears ...its a beast , However; I have a deceleration vibration I think is due to pinion angle from 1 piece carbon fiber drive shaft. I cant find shims or solution for irs rear ends, maybe shims for transmission mounts to change pitch angle?

 
OP
OP

db252

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Shims can be easily added to the transmission cross member mount to lower the angle. You can also raise depending on the angle you’re going after with the trans mount to cross member.
 

09jsw

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I have the same set up except I went with rxt clutch and 355 gears ...its a beast , However; I have a deceleration vibration I think is due to pinion angle from 1 piece carbon fiber drive shaft. I cant find shims or solution for irs rear ends, maybe shims for transmission mounts to change pitch angle?
You shim the trans crossmember and or the rear subframe.
 

dodger789

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J17GT

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Finished the break-in yesterday and finally made some WOT pulls with the magnum & new clutch. Proceeded to blow the slave cylinder on the second pull. Left me stranded on the side of the highway. Leaked fluid all over the ground.

WTF.... I really hate this hobby sometimes.
 


dodger789

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Shims can be easily added to the transmission cross member mount to lower the angle. You can also raise depending on the angle you’re going after with the trans mount to cross member.
Thank you.
 

dodger789

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Took on a new project and thought I’d share it. Never thought I’d go this route but but just saying that doesn’t really surprise me.

Backstory: The car is a 16 PP so it has the 3:73 rear gears and is pretty heavily modified. Like most of us, I ran the MT82 with an MGW and had no real issue especially after adding that shifter. I didn’t break anything in my stock transmission and it worked the same from the day I bought till the day I took it out. For 28k miles I ran the stock clutch with it and I was fairly quick to add a Whipple and shortly after that E85. I was amazed at how well the stock clutch handled it. I do occasional road course days, and as some forum members can attest to from riding shotgun, I push the car hard and play with the line of limit. The 3:73 differential made 1st and 2nd gear pretty useless at my power level and considered changing diffs but didn’t want to ditch my Torsen. I don’t do 1/4 mile runs and for the most part I daily drive the car which includes commuting to work in traffic. The car is literally 95% street with casual manners and 5% track/canyon carving/hurt the feelings of another car brand/owner that unwisely has challenged.

I bring up this info because it has a factor in making choices in parts and gear selection. Also, my baseline is can my wife take the car out and drive it ‘normally’ without it being annoying/difficult to operate and that applies to me as well.

This is what I ended up buying and most of this comes in a kit which is the route I went:

Tremec Magnum XL transmission (duh)
First gear choice of 2.66 and opted for the 5th and 6th OD gears of the 2.97 trans which gives me in order of 1st to 6th, 2.66/1.78/1.30/1.00/.80/.63

Quick Time steel sfi bell housing

QA1 carbon fiber driveshaft with sfi (upgrade)

Bowler all-in-one harness for electronic connections

Rest of the kit included fluids, transmission mount, cross brace and mounting hardware

Also added the MGW shifter since I really appreciated what it did for the MT82


The clutch was a difficult and time consuming process and there is a endless amount of choices out there. Everyone has their preferred brand or special purpose for what their plans are for their car but this is also the reason I gave the back story above because it applies here. I would love to try all brands and models that I narrowed it down to (probably 5) but I’m not sponsored, a company that works in the industry nor someone with unlimited funds. My personal requirements were something near stock weight for stored energy, sprung hub and organic. I was open to single and dual disc setups knowing the inherent differences. Ultimately I went with the Ram Pro Series twin disc organic with steel flywheel.

Like I said, plenty of great choices to go with and I even tried for a short period, which was completely non cost effective for me, a Mantic 9000 organic series clutch which I will say was awesome with my MT82 the short time I had it. I could have easily just switched to 26 spline clutch discs but the light weight would have been an issue I feared so I did what I did.


Here’s some pics cuz that’s all most care about....

22B49E1B-D50F-436C-8D25-BF15FB08BE02.jpeg

6F75DE80-E680-4CFC-A1B1-79D7614C8285.jpeg
4EEB91A5-CB7B-46BF-AC05-FD2E63C79518.jpeg
5316F36B-7B02-4B19-85D2-746393F7A482.jpeg
28D8580D-70AB-4442-8B8B-6D04C3C7D196.jpeg
6D8013D6-5E5C-4CF1-B8EC-9732C8F707FB.jpeg
2A732B9A-D5B2-42D9-ADDD-71EAA031D3A8.jpeg
44345936-FA41-4B18-8A90-4EF865C8DB32.jpeg
FDF58B3C-984D-48CC-929C-8A8EC1A031B2.jpeg
48AC3E88-F9B9-4B38-BFFD-0125387C2188.jpeg
AF199552-9E96-4436-AB2F-DD5381D69DF9.jpeg
0E141C3E-4926-4F70-9BF8-C8BFF73D100A.jpeg
D755A471-DCA2-4C02-ABB4-32806973BAC0.jpeg
5178D562-26E9-4DBD-AA2F-D5730049969D.jpeg
8AA3B291-D17F-44E3-8577-D37B1B34F706.jpeg


At current writing, I’m around 300 miles on the break in. At first, and at around only 25 miles I thought I made a mistake with clutch choice. First gear start off from a stop had significant chatter but that has quickly become better and better and I’m sure will continue to get better as smooth slipping start off has become an easy thing to do now. Recently took the wife out to mess around with first gear in a parking lot and she did great but could notice the current difference. If you’re already moving, this clutch is just perfect. Clutch pedal effort is less than stock, initial grab and capture is well within the throw of the clutch pedal; not quick off the floor grab or late grab near the top. I’m 90% happier with the clutch than my first quick to judge impression.

I cannot say enough about the transmission. I absolutely LOVE the gears I chose granted I’m in the break in phase and not shifting over 4000 rpm for the most part but again, this is how the car will be driven most of the time. First and second gear are so much more useful and enjoyable to use. Fourth gear (1.30) in the MT82 was one of my most favorite gears to play in and also was a factor in choosing the magnum gear selection I did because third gear in this set is also 1.30 which made it perfect. 4th is now the 1:1 gear which I like and the two OD gears are gapped perfectly unlike our 5th to 6th is in the 15-17 MT82. I will say it is weird downshifting to 1st gear around corners in residential/commercial zones but it’s easy, called for and works like any other gear you’d be used to using normally. Hell, I’m still learning what gear to be in based on muscle memory of where the shifter used to be. I really couldn’t be happier with how this all works together and with the stock 3:73.

The driveshaft is awesome and the second QA1 I have owned and also part of the not a wise investment in regards to how long I had it in the car before switching to the Tremec. I’m sure it’s not the last time I’ll do that.

One other thing when I first got it on the road and getting a feel for it. There was a small vibration/drone in the car that came in around 3200 rpm and went out around 3800 rpm. Believe me I thought of every possible scenario and incorporated lots of others thoughts to the mix so before you start throwing out ideas, it was figured out. There is a reverse lockout solenoid that is on the drivers side tail section of the transmission and it was touching the body lightly. The idea of what to do was easy but the process of doing it wasn’t quite so easy especially without removing things. It took a small hydraulic ram to push, which happens to be a much stronger and stiffer section than I expected, the body panel away which now looks like this, totally fixed the issue and might as well be a mile away compared to what was before.

40801D28-C54B-49BF-A636-203E29CABFD4.jpeg


This is the electronic harness that was included with the kit and sold from Bowler. It incorporates all electrical connections and really made everything work easily and its adjustable for things such as tire size, OOS pulse calibration and reverse lockout parameters to make to your liking (speed at which lockout engages or deactivates). Reverse switch is a no brainer. Literally soldering 5 total wires to the original trans harness to make everything connect; the two reverse wires and reverse camera and light work like stock. Positive, ground and oss wire.....done. You download an app to your iPhone or android and and it Bluetooth connects when ever you want for changing parameters. Without going into too much detail, just go with it’s easy and works great. All connectors to the sensors on the trans are OE style and weather sealed.

429687FE-49C6-4C87-BA46-9CD49225392E.jpeg


In regards to the actual install, it’s no more difficult than changing a clutch if you’re comfortable with it. I really liked the separate bell housing.

That’s all I got for now. Still have miles to go before it all gets more aggressive testing but I have no doubts.
same set up with me however I went with 355 ford performance gears and mcleod rxt twin. I am dealing with snapping twisting half shafts and driveline vibrations with duel fore fuel pumps that are overheating my fuel tank...I hooked up a digital thermometer to my fuel hat. I try to bring it on home at 112 degrees f. I am humiliating everything on the road including street bikes. I will be sixty years old in October and I refuse to grow up. Yes the metal near the trans is very soft on the body, I think I smashed through it myself making room for the tremek. Tires are over $700 for only 2 every 3 months if you want to hook.
 

J17GT

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Finished the break-in yesterday and finally made some WOT pulls with the magnum & new clutch. Proceeded to blow the slave cylinder on the second pull. Left me stranded on the side of the highway. Leaked fluid all over the ground.

WTF.... I really hate this hobby sometimes.
Back from the dead as I wanted to give an update on my situation and help out the next guy so they don't have to go through what I am. As mentioned, I blew the hydraulic slave on the second WOT shift after breaking in the magnum and new McLeod RXT clutch. When everything was initially installed, I always thought the trans was really notchy and the clutch engagement was way too close to the floor and felt weird....

I finally got some motivation to work on the car a month ago and removed the trans to inspect things. McLeod had me take a number of measurements and it was determined I was over extending the slave...by a lot. I'm running the sprung hub RXT twin disc with matching flywheel with the correct shorter Ford slave cylinder (from a GT500). This is supposed to be a plug and play setup with the magnum, but it sure wasn't. This is the setup: CLICK ME

It was determined that I need a .450" shim behind the slave to put it in the right place and have the correct air gap. To me that is a huge number! My setup wasn't even close... I will say McLeod was great to work with and really wanted to help get my setup correct. They said there are a handful of guys they are working with right now with this exact problem.

As mentioned, McLeod had me take a bunch of measurements, but this video shows the mose critical: A and B measurement video

I'm not sure if Tremec changed something with the gearbox or my setup is just goofy. But no matter the clutch you are going to put in your car, do those measurements to ensure the air gap is correct!!
 

Calvin

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Back from the dead as I wanted to give an update on my situation and help out the next guy so they don't have to go through what I am. As mentioned, I blew the hydraulic slave on the second WOT shift after breaking in the magnum and new McLeod RXT clutch. When everything was initially installed, I always thought the trans was really notchy and the clutch engagement was way too close to the floor and felt weird....

I finally got some motivation to work on the car a month ago and removed the trans to inspect things. McLeod had me take a number of measurements and it was determined I was over extending the slave...by a lot. I'm running the sprung hub RXT twin disc with matching flywheel with the correct shorter Ford slave cylinder (from a GT500). This is supposed to be a plug and play setup with the magnum, but it sure wasn't. This is the setup: CLICK ME

It was determined that I need a .450" shim behind the slave to put it in the right place and have the correct air gap. To me that is a huge number! My setup wasn't even close... I will say McLeod was great to work with and really wanted to help get my setup correct. They said there are a handful of guys they are working with right now with this exact problem.

As mentioned, McLeod had me take a bunch of measurements, but this video shows the mose critical: A and B measurement video

I'm not sure if Tremec changed something with the gearbox or my setup is just goofy. But no matter the clutch you are going to put in your car, do those measurements to ensure the air gap is correct!!
That brings back some memories. I blew 2 slave cylinders before I went with the McLeod adjustable one. (Running the twin disk Spec clutch) The second time it happened, it took out my 2nd gear blocker ring so I ended up changing the blockers and shift pads to carbon and brass respectively. I still have to adjust my McLeod one from time to time or I can physically feel the slave overextending. Starting to do it slightly now after over a year without adjustment.

Random unnecessary info. I run the Ram pedal adjuster and a dry break fitting to allow me to dial in pedal engagement and allow for easy trans removal without having to bleed it all the time. Ran this setup for 3 years ~50k miles with minor issues.
 

J17GT

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Another interesting measurement was the face of the bellhousing to the mounting surface of the slave. On the Magnum it was 6.5" on my MT82 it's 6.1875". The slave isn't remotely in the same place. Even a stock clutch setup for my year car would not have worked with the magnum.

I also measured from the tip of the input shaft to the bellhousing face. That measurement was the same on the magnum and MT82.
 

Ruiner46

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Thanks for the great info, but man, this was really not what I wanted to read as my car is almost back together again after doing fuel system and headers. I have the exact same clutch setup.

Did you have any other symptoms aside from general notchiness? Did the car want to creep forward if the clutch pedal was pressed and you gave it a rev, or anything like that? Have you shimmed it already and confirmed that it's fixed?
 

J17GT

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Thanks for the great info, but man, this was really not what I wanted to read as my car is almost back together again after doing fuel system and headers. I have the exact same clutch setup.

Did you have any other symptoms aside from general notchiness? Did the car want to creep forward if the clutch pedal was pressed and you gave it a rev, or anything like that? Have you shimmed it already and confirmed that it's fixed?
The symptoms were shift quality and the clutch engagement point being super close to the floor. Downshifts to second were particularly rough. I did do the typical clutch drag tests, including rev it in gear with the clutch down and the car did not creep.

I do not have things back together yet. I sent my clutch and flywheel to McLeod for inspection and they also balanced it all for me. The clutch, flywheel and shim shipped out to me yesterday. I plan to take those 'A' and 'B' measurements again (with the shim) just to confirm the air gap is where McLeod wants it prior to putting the trans back in the car.

The weather is garbage here and cold, so not sure when I'll get it done. Could be a bit. No heat in my garage!
 

Red65

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The symptoms were shift quality and the clutch engagement point being super close to the floor. Downshifts to second were particularly rough. I did do the typical clutch drag tests, including rev it in gear with the clutch down and the car did not creep.

I do not have things back together yet. I sent my clutch and flywheel to McLeod for inspection and they also balanced it all for me. The clutch, flywheel and shim shipped out to me yesterday. I plan to take those 'A' and 'B' measurements again (with the shim) just to confirm the air gap is where McLeod wants it prior to putting the trans back in the car.

The weather is garbage here and cold, so not sure when I'll get it done. Could be a bit. No heat in my garage!
Are you still running the rev match upshift that comes in the car from the factory, or did you have it disabled? If you're still running it, does it play weird with the magnum ratios?
 

J17GT

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Are you still running the rev match upshift that comes in the car from the factory, or did you have it disabled? If you're still running it, does it play weird with the magnum ratios?
I am not. The tune I have in the car for the magnum disables that. My understanding is leaving that enabled causing strange rev hang issues between shifts.
 

 
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