Has anyone done the Magnum XL swap and regretted it?

[EF1]

I have the Tremec T56 Magnum and it's junk. I'm not sure why everyone here thinks it's great. The shifting from 1-2, and 2-3 keeps getting harder and harder, these days it occasionally grinds. I'm using the tremec fluid (since they recently changed this to the fluid they recommend on their website). I've even dropped the trans, packed it up and sent it to the factory, they returned it with an "everything is fine" diagnosis. I originally bought the trans in a kit from JPC and it all seemed to fit together well. but that McLeod dual disc clutch was WAY too loud. I replaced it with an Exedy mach 500, and now the clutch pedal is almost on the floor. maybe it needs a shim, though there was nothing in the instructions about it.

All I've done is make my car undriveable. I shoulda' waited for new Corvette

It sounds like you have a clutch problem, not a transmission problem. If the clutch is going all the way to the floor and it is hard shifting it sounds like the clutch is not fully engaging which causes hard shifting and eventually will lead to synchro damage in the transmission. Did you measure the slave throw when you were installing? You may have the wrong slave cylinder or a clutch master cylinder issue.

 

[cgornowich]

If you mean locating the centerline of the crankshaft with centerline of the transmission mainshaft, I'm not sure. The bellhousing that came with the kit from JPC was a quicktime bellhousing that uses locating dowels, I was aware that there was an adjustment to be made. If you mean the depth of the clutch throwout (or whatever it's called) it seems off, I mean the engagement point should not be on the floor.

I'm so disappointed in the car. I finally got the engine running well (thanks LITO!) and she handles OK (long story), but this transmission just gets worse every time I pull it out...

 

[cgornowich]

It sounds like you have a clutch problem, not a transmission problem. If the clutch is going all the way to the floor and it is hard shifting it sounds like the clutch is not fully engaging which causes hard shifting and eventually will lead to synchro damage in the transmission. Did you measure the slave throw when you were installing? You may have the wrong slave cylinder or a clutch master cylinder issue.

I did not measure the slave throw, how do I do that? It's time for another flywheel and clutch.

 

[cgornowich]

I did not measure the slave throw, how do I do that? It's time for another flywheel and clutch.

I was not aware they're were different slave cylinders for this car. I'm using a ford racing 4.6 block (26 spline shaft) a quicktime bellhousing (from the JPC kit) and a Magnum T56.
I threw a rod in the original 4.6 at summit point and threw in a new motor (lots of ford racing stuff, shortblock, CNC heads, mild cams, and smaller supercharger puller) and a LITO tune. She has too much power, traction is the major issue. I had a McLeod dual disc clutch that was WAY too loud, but worked well. I should have left it in... Swapped it for with an Exedy mach 500 (I think) and.... Oh hell, I'm getting tired of installing clutches....

Any suggestions on a good clutch that is good for 550 RWHP and not too loud?

 

[EF1]

I did not measure the slave throw, how do I do that? It's time for another flywheel and clutch.

I meant disengaged in my post. To measure I followed instructions provided by Mantic Clutch. You bolt the bell housing to the motor without the trans attached and measure from the face of the bell housing to the clutch fingers. Then you measure from the front of the slave to the mounting flange where the trans bolts to the bell housing. The second measurement should be .5 to .625 greater than the first to ensure the the slave has enough preload and will fully disengage the clutch. Here is a link to one of their install guides.

https://cdn.shopify.com/s/files/1/1852/5357/files/GTB_118_T56_Mag_XL_Mustang_Mantic_Triple_Disc_Installation.pdf?v=1624711275

 

[EF1]

I was not aware they're were different slave cylinders for this car. I'm using a ford racing 4.6 block (26 spline shaft) a quicktime bellhousing (from the JPC kit) and a Magnum T56.
I threw a rod in the original 4.6 at summit point and threw in a new motor (lots of ford racing stuff, shortblock, CNC heads, mild cams, and smaller supercharger puller) and a LITO tune. She has too much power, traction is the major issue. I had a McLeod dual disc clutch that was WAY too loud, but worked well. I should have left it in... Swapped it for with an Exedy mach 500 (I think) and.... Oh hell, I'm getting tired of installing clutches....

Any suggestions on a good clutch that is good for 550 RWHP and not too loud?

I believe there were 2 different slaves used on S197's. The 4.6 liter used a different part # than the 5.0 liter coyotes. Some configurations may need shimming. I think 550rwhp is a bit much for a Mach 500. I see a lot of recommendations on the Exedy Super Single for track use. I am using a Mantic Twin Disk between my Gen 1 coyote and the Magnum XL. It is overkill for my 450rwhp car, but I wanted a light pedal due to a bad knee.

 

[67GTA]

I'm so disappointed in the car. I finally got the engine running well (thanks LITO!) and she handles OK (long story), but this transmission just gets worse every time I pull it out...

Totally understand, but don’t give up on it! I’ve had my share of steep learning curve to get this combo dialed in, but once it’s right, it’s soooo worth the effort. The process that @EF1 linked above, along with this process to make sure the bellhousing is dead center:

 

[EF1]

If you mean locating the centerline of the crankshaft with centerline of the transmission mainshaft, I'm not sure. The bellhousing that came with the kit from JPC was a quicktime bellhousing that uses locating dowels, I was aware that there was an adjustment to be made. If you mean the depth of the clutch throwout (or whatever it's called) it seems off, I mean the engagement point should not be on the floor.

I'm so disappointed in the car. I finally got the engine running well (thanks LITO!) and she handles OK (long story), but this transmission just gets worse every time I pull it out...

You should check the concentricity of the bell housing to the crank shaft as in the link posted by 67GTA. If it is off you realign it with offset dowel pins. If it is out of spec it will tear up the bearing on the trans input shaft and would be noticeable to Tremec if you make a warranty claim. The hard shifting really sounds like a clutch issue. The engagement point should not be all the way to the floor.

 

[cgornowich]

You should check the concentricity of the bell housing to the crank shaft as in the link posted by 67GTA. If it is off you realign it with offset dowel pins. If it is out of spec it will tear up the bearing on the trans input shaft and would be noticeable to Tremec if you make a warranty claim. The hard shifting really sounds like a clutch issue. The engagement point should not be all the way to the floor.

Here's a picture of when I removed the McLeod RST. The dowel pins are large ( I dunno, 1/2 ID ) and I was not aware there were offset ones available. If you know of some, please give me a clue so I can search for them.

 

[cgornowich]

I believe there were 2 different slaves used on S197's. The 4.6 liter used a different part # than the 5.0 liter coyotes. Some configurations may need shimming. I think 550rwhp is a bit much for a Mach 500. I see a lot of recommendations on the Exedy Super Single for track use. I am using a Mantic Twin Disk between my Gen 1 coyote and the Magnum XL. It is overkill for my 450rwhp car, but I wanted a light pedal due to a bad knee.

I thought the mach 500 was strong enough, and it has not been slipping a noticeable amount, so it might be OK. But she now leaking a few drops of oil when parked, I used the lube that was recommended on the flywheel bolts, and I'm wondering if I should have used sealant instead. Evidently the bolt holes in the crank actually go clear to the oil passageways, and they can leak a small amount. I'm betting the flywheel is now roached and took the clutch with it. So, time to start all over.

Do you like the Mantic Twin Disc? and (everyone gives me a hard time for asking) is it loud? does it rattle and transmit that horrible grinding noise around 2k RPM? If not, I might have to look into it. Let me know your thoughts.

 

[TMSBOSS]

I have the RST and yes, it is noisy around 2k. It works great. With a NA Coyote (roadrunner) you don’t spend a whole lot of time at low RPMs. My point, you may need to accept the noise at low RPMs with a performance clutch. I am still running the original MT-82. A “Working” clutch is the key.
The frustrations of putting in parts and not getting the performance you paid for is something most of us have worked through. Some of the solution will be in the adjustments. Sometime it’s “Other Parts”.
Check alignment and depths. The devil is in the details.

 

[EF1]

Here's a picture of when I removed the McLeod RST. The dowel pins are large ( I dunno, 1/2 ID ) and I was not aware there were offset ones available. If you know of some, please give me a clue so I can search for them.

View attachment 82532

I apologize but this may be a long post for some. Okay lets start from the beginning. Before installing you should have run the transmission through all gears turning it over by hand to make sure everything was smooth and no grinding. The alignment of the bell housing to the block should have been measured using the method in the video that 67GTA linked above. If the bell housing isn't properly aligned with the block you may get a vibration or out of balance situation that will wear the front bearings in the transmission. If this happens Tremec will not cover it under warranty, but it shouldn't cause the shifting issue you are experiencing.

Offset alignment pins are available through Tremec distributors such as Silver Sport, Modern Driveline, American Powertrain, etc. One end is round just like the straight pins that came with your kit. The other end is more oval shaped and you can feel a shoulder where they transition from straight to offset. The pins come in different amount of offsets depending on how far out of alignment a particular bell housing is. This allows you to clock the bell housing if it does not measure within spec to properly align the transmission input shaft to the crank. Most do not need the offset pins but some do depending on application. Since you are running a freshly built engine the crank may not be in the exact same place as a factory engine due to machining and may need aligning.

Now for the shifting issue. If the Mcleod clutch shifted fine and the problems didn't start until the Exedy install it is most likely the clutch. Does the transmission shift smoothly when the engine is not running? If so, I believe the clutch is not fully disengaging, especially if the engagement point is very low. You can test this if the transmission is still in the car. Jack the rear wheels off the ground and place on stands. Place in first gear with the clutch fully depressed and start the car. If the wheels move the clutch is not disengaging. Also, with the car off and the car in gear and foot off the clutch have someone try and spin the rear wheels while you slowly depress the clutch. Note where the pedal is when the wheels start to move and continue down to see how much travel you actually have.

This is a starting point to get you back on the right track. If you want to take this offline let me know and I will help with what I can. I just put a Magnum XL behind by coyote this summer and it is still pretty fresh in my mind.

 

[EF1]

I thought the mach 500 was strong enough, and it has not been slipping a noticeable amount, so it might be OK. But she now leaking a few drops of oil when parked, I used the lube that was recommended on the flywheel bolts, and I'm wondering if I should have used sealant instead. Evidently the bolt holes in the crank actually go clear to the oil passageways, and they can leak a small amount. I'm betting the flywheel is now roached and took the clutch with it. So, time to start all over.

Do you like the Mantic Twin Disc? and (everyone gives me a hard time for asking) is it loud? does it rattle and transmit that horrible grinding noise around 2k RPM? If not, I might have to look into it. Let me know your thoughts.

I like the Mantic. It isn't cheap but it is a complete package down to the ARP flywheel bolts. The customer service received from Geoff has been the best I have seen in years. All twin disks make some noise when sitting still idling due to the design. Noisy is such a subjective term. What bothers one doesn't another. A better question may be how does the noise level compare to the Mcleod RST?. That I can't answer. I have not been in a car with an RST for comparison. My car is still in the body shop from the hit I took on track in October. I should have it back in the next week or so. I could shoot a short video clip sitting in the car to send you to get an idea of relative noise at a given rpm range if it helps.

 

[cgornowich]

I like the Mantic. It isn't cheap but it is a complete package down to the ARP flywheel bolts. The customer service received from Geoff has been the best I have seen in years. All twin disks make some noise when sitting still idling due to the design. Noisy is such a subjective term. What bothers one doesn't another. A better question may be how does the noise level compare to the Mcleod RST?. That I can't answer. I have not been in a car with an RST for comparison. My car is still in the body shop from the hit I took on track in October. I should have it back in the next week or so. I could shoot a short video clip sitting in the car to send you to get an idea of relative noise at a given rpm range if it helps.

I like the Mantic. It isn't cheap but it is a complete package down to the ARP flywheel bolts. The customer service received from Geoff has been the best I have seen in years. All twin disks make some noise when sitting still idling due to the design. Noisy is such a subjective term. What bothers one doesn't another. A better question may be how does the noise level compare to the Mcleod RST?. That I can't answer. I have not been in a car with an RST for comparison. My car is still in the body shop from the hit I took on track in October. I should have it back in the next week or so. I could shoot a short video clip sitting in the car to send you to get an idea of relative noise at a given rpm range if it helps.

Eric, I appreciate yours and 67GTA's input. It's clear the time has come for another clutch. This time I'll take my time and pay attention to the details. I'm thinking the symptoms are caused by a number of issues:
1. Engine oil leaking on to the flywheel surface due to no sealant on the flywheel bolts. I never knew this was a thing, but evidently the ford racing shortblock has requires sealant on the flywheel threads, due to the threads going clear to the oil passage in the crank. This could causing the slight vibration starting off in first gear. I don't recall this being an issue with the RST, but I don't recall. Now there's only a few drops when I park the car, but it's feels like engine oil.
2. Difficult to engage 1st and 2nd gear. This is probably caused by the bellhousing out of alignment, either the surfaces are not mating flatly or they are out of alignment axially.
3. Starting off in 1st and especially reverse the car shudders. No amount of feathering the clutch can stop this and it is so bad I can feel the vibration in the seat.
4. The "noise" I keep whing about at 2k RPM in 1st, 2nd, 3rd, and 4th gear is probably due to a number of issues: the RST not having "sprung hubs" or "damper springs:, the alignment issues in #2 above, and the oil on the flywheel surface. All three of these issues probably make the noise worse. To be clear, this is not a little noise, it sounds like a coffee can half full of rocks being thrown around. It is so loud I cannot talk loud enough to be heard.

If I address all these issues, hopefully the car will be drivable again.

If I only had one project things would be easier. I need a bigger garage...

Charlie

 

[EF1]

Eric, I appreciate yours and 67GTA's input. It's clear the time has come for another clutch. This time I'll take my time and pay attention to the details. I'm thinking the symptoms are caused by a number of issues:
1. Engine oil leaking on to the flywheel surface due to no sealant on the flywheel bolts. I never knew this was a thing, but evidently the ford racing shortblock has requires sealant on the flywheel threads, due to the threads going clear to the oil passage in the crank. This could causing the slight vibration starting off in first gear. I don't recall this being an issue with the RST, but I don't recall. Now there's only a few drops when I park the car, but it's feels like engine oil.
2. Difficult to engage 1st and 2nd gear. This is probably caused by the bellhousing out of alignment, either the surfaces are not mating flatly or they are out of alignment axially.
3. Starting off in 1st and especially reverse the car shudders. No amount of feathering the clutch can stop this and it is so bad I can feel the vibration in the seat.
4. The "noise" I keep whing about at 2k RPM in 1st, 2nd, 3rd, and 4th gear is probably due to a number of issues: the RST not having "sprung hubs" or "damper springs:, the alignment issues in #2 above, and the oil on the flywheel surface. All three of these issues probably make the noise worse. To be clear, this is not a little noise, it sounds like a coffee can half full of rocks being thrown around. It is so loud I cannot talk loud enough to be heard.

If I address all these issues, hopefully the car will be drivable again.

If I only had one project things would be easier. I need a bigger garage...

Charlie

View attachment 82548

1. I can't speak to. I don't have any experience with the 4.6. I have a gen 1 coyote
2. The bell housing being out of alignment shouldn't cause shifting issues. This is usually the clutch. If it was out of alignment Tremec should have detected bearing wear when you sent it to them.
3. Again this really sounds like the clutch.
4. I get some rattling with the Mantic when stopped, but no noticeable noise when in gear moving down the road at any speed or rpm. The Mantic I am using has the cerametallic sprung hub disks.

I am not real familiar with JPC as a supplier, but you may want to try and get tech support out of one of the Tremec Elite distributors. There are only 6-8 in the country and the smaller dealers get their Tremec swap kits from them. They provide tech support via email and telephone. These guys live transmission swaps and are very knowledgeable and helpful. I am fortunate in that I live between 2 of them. It was unfortunate that neither of them had the close ratio magnum xl in stock and did not know when they would receive any. I had to have one shipped from the other side of the country.

If there is anything I can help with let me know.

 

[cgornowich]

I ordered a Mantic Clutch kit yesterday, their dual "sprung" disc (organic), Item number M924235.

Here's a link (and it's a long one)

Shelby GT500KR, 6 Speed, 1/08-12/09 - 5.4 Ltr, V8 Supercharged, 403kw - 2008 - Mustang - Ford

where can i find cheap auto parts online, clutch kit, clutch kit and flywheel, automotive transmissions, modified 79 series landcruiser, double clutches, slave cylinders, machining flywheel, clutch master cylinders, clutch for a car, landcruiser modifications, clutch replace, clutch kit, dual...

www.manticclutch.com

It's the cheapest one on the page....

Looks like a very nice, complete, kit. I'll post when it arrives and we'll get started on the last clutch I'm ever gonna need...

Charlie

 

[EF1]

I have the cerametallic twin disk. Geoff recommended it over the organic since my car doesn't see much road use these days. He said it would handle the heat better. I haven't seen many on this forum use the Mantic. Let us know how you like it. Also, let us know what you find when you pull the trans again. I am curious as to what is causing the shudder you described. I am thinking the clutch disk may have be contaminated with oil if it has worked past the bolts and slung it around inside the bell housing.

 

[EF1]

I ordered a Mantic Clutch kit yesterday, their dual "sprung" disc (organic), Item number M924235.

Here's a link (and it's a long one)

Shelby GT500KR, 6 Speed, 1/08-12/09 - 5.4 Ltr, V8 Supercharged, 403kw - 2008 - Mustang - Ford

where can i find cheap auto parts online, clutch kit, clutch kit and flywheel, automotive transmissions, modified 79 series landcruiser, double clutches, slave cylinders, machining flywheel, clutch master cylinders, clutch for a car, landcruiser modifications, clutch replace, clutch kit, dual...

www.manticclutch.com

It's the cheapest one on the page....

Looks like a very nice, complete, kit. I'll post when it arrives and we'll get started on the last clutch I'm ever gonna need...

Charlie

I just noticed your mantic clutch link takes you to the corporate page in Australia. There is a U.S. distributor located in North Carolina. There address is www.manticclutchusa.com

 

[cgornowich]

I just noticed your mantic clutch link takes you to the corporate page in Australia. There is a U.S. distributor located in North Carolina. There address is www.manticclutchusa.com

When comparing prices for the Mantic clutch, I was shocked to see that I could purchase it directly from the manufacturer in Australia for $1,230 while the distributors here in the US were asking $2,250 and up. And it ships from "down under" in 10 days. While it might be logistically challenging if it needs to be returned, I'm willing to roll the dice. I'll you know how it goes...

 

[Scootsmcgreggor]

When comparing prices for the Mantic clutch, I was shocked to see that I could purchase it directly from the manufacturer in Australia for $1,230 while the distributors here in the US were asking $2,250 and up. And it ships from "down under" in 10 days. While it might be logistically challenging if it needs to be returned, I'm willing to roll the dice. I'll you know how it goes...

holy crap that's amazing if no duties. Did you get an HTS code and check the duty rate? Please do let us know how it goes.