T-56 Magnum Swap Considerations

LV_Ford_Fan

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This was written as a guide for anyone planning on making a Magnum swap. It's just a list and not a how-to since I have not done the swap yet.

I have looked at many threads here, YouTube videos, and other things to put this together. I want to stay with facts and not opinions and not mention any vendors by name.

There are three Magnum models for our cars:

TUET-11010 - Ratios 2.66 1.78 1.30 1.00 .80 .63
TUET-11011 - Ratios 2.97 2.07 1.43 1.00 .74 .50
TUET-16884 - Ratios 2.97 2.07 1.43 1.00 .80 .63

Note: Some vendors offer swap kits which include the transmission and one or more parts mentioned below.

The Input shaft is 26 spline so a 26 spline clutch disk is required.

The Output shaft is 31 spline so a 31 spline yoke is required.

The Magnum is longer that stock so the stock driveshaft needs to be shortened or a custom driveshaft is needed. Remember the 31 spine yoke requirement.

The Magnum does not quite fit the stock crossmember so the crossmember needs to be modified or an aftermarket crossmember needs to be used.

The wiring harness will fit but not in the stock location so zip ties can be used to secure it. There are pigtails available to modify the wiring if so desired.

There may be some interference with the Magnum shifter area so the tunnel can be modified or low profile shifter bolts can be used.

There may be some interference with the case prongs that protect the switch on the right front area of the case. You can see on the stock transmission these have been shaved down. Some people have shaved down the Magnum case and some have used a hammer on the tunnel to make room. This is reported to be a small amount.

Reports have shown that the stock shifter handle does not work well with the Magnum but there are aftermarket handles that have been adapted.

There are aftermarket complete shifters available. Complete shifters for the stock T-56 won't work.

The Magnum mechanical speedometer hole comes with a rubber plug. There are aftermarket metal plugs available.

There are reports of a missing hole for the clutch dust cover bolt.

There are reports of the clutch fork needing to be ground down to clear the case for taller clutch configurations.

Let me know if I missed anything on my list. Remember I am trying to stay with facts and not opinions.
 

DSG2003Mach1

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depending on the clutch/flywheel combo an adjustable height pivot ball is needed - you will likely have to pull the trans a few times to get the depth set correctly, make sure to account for needed travel as the clutch disc(s) wear

The Stiflers trans mount with drive shaft loop worked perfect for me.

I would highly suggest using RTV on the shifter, not a gasket. If they compress/tear/degrade you may have to pull the trans to re-seal it as you can't get to all the bolts. I can't remember if it's my Steeda K-member or Moroso oil pan but one of them prevents getting enough meaningful tilt to access anything.

There is a seal in the bottom of the red Tremec shifter - if it's out I would check/replace this seal, again, real bitch to replace with trans in car. Now this is speculative but there is anecdotal evidence that something in the Amsoil ATF accelerates wear on this seal.

If buying a used Magnum there were some early ones that had issues building up pressure and blowing out the tailshaft seal - the options to repair are a new design tailshaft seal that has some metal reinforcement in there, if it still blows that out a new tail assembly is needed or have a machine shop add a vent.




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Hopefully you're ok with me tagging in some items for non-terminator owners making the swap:

The pig tails wont match if you come from a 3650 or other older transmission. You can buy the appropriate plugs at any auto parts store, just de-pin the connectors and swap onto the existing harness.

There is NO provision for the reverse lock out in the pcm, you can either live with it, run a wire to the brake light switch (just remember if you're lightly on the brakes in say 6th and go for 5th someone could conceivably **** around and end up in R instead), cut the spring, or use one of the reverse lockout boxes which make it behave like factory.
 

96dreamer

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Something to consider when checking pivot ball height. You can remove the front cover plate from the transmission and drill out the pivot ball hole. Then grind a slot in the back of the bivot ball and adjust it with the front plate installed. May keep you from pulling the trans a bunch to get it right. Then just use rtv on the threads of the pivot ball when final installing. This applies to non magnum t56's as well.
 

LV_Ford_Fan

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Since I already have the cover off my stock T-56 I can try that. Then put that same adjustment on the Magnum. Hopefully it will be a better starting point and I would not need to pull the cover off a brand new Magnum.
 

03' White Snake

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Good list, I think you have everything I ran into covered. Cobra guys can reuse the stock bell housing or get a QuickTime steel one.

I’d recommend ditching the stock magnum shifter right off the bat. Went thru 2 of the seals with less than 1200 miles on it. The linkage on the bottom of the shifter pushes against this seal and blows them out. Very poor design. You will know real quick when it goes bad…. Insulation under the carpet gets soaked in trans fluid and that’s all you can smell in the car.
 

MG0h3

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After replacing two of those seals I tore a 3rd and got the Hanlon Motorsports shifter.

It’s also lower profile so less need to hammer the tunnel.

I ran stock pivot ball with an RXT and Fidanza flywheel. Aluminum one. I liked the engagement like that personally. Going to give you a lighter pedal as well with more leverage and throw.

Almost all will shorten 4-5mm and be just fine. The pivot ball height changes your final engagement point pedal height. By shortening it, you’re fully engaged sooner.

I clearanced the face of the trans a touch on a couple of the ribs. This is really only an issue on taller twin disc clutches.






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03' White Snake

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I certainly don't want to have a leak after all that work, so that is good advice. Thanks.
Yup. Spend the $250 on a shifter now and save the headache. I run a Tick Shifter. Springs were crazy tight when new, after 1 summer it’s more manageable now. I really like it.

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LV_Ford_Fan

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Thanks for all the input so far. I will add the shifter leaking issue, the pivot ball, and the case clearance (I already had clutch fork clearance on my list). I did not want to mention specific brands on my list, but I can add suggested part brands later. I want to get more replies before I do that.
 

DCguy

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This issue of clearance and clutch fork travel is only really an issue when using the magnum with twin disk clutches like you stated..

There are some twin disk clutch kits that have a lower overall stack height than others. For example, the Centerforce DYAD's have a recessed flywheel which allows for a more condensed overall package and thus requires no grinding of the clutch fork / trans case in order to get the necessary engagement points dialed in.

I always try to shorten the pivot ball by as much possible while still having the TOB engage the clutch fingers slightly in neutral....to make sure you have it set correct easiest is to get the rear wheels off the ground and make sure they're not spinning while in neutral.....You should be able to disengage the TOB by slightly pulling back on the clutch fork by hand....anyway, that's how i've been doing it and seems to work well.

The end goal is to have your clutch engage at the center of pedal travel or a tad sooner......i've driven cars where it engages at the very top due to poor pivot ball adjustment or too tall of a clutch stack. Not a fun car to drive IMO. Maximum motorsports also sells a clutch pedal bracket kit that helps to lower the clutch pedal a bit so that it's more level with the brake pedal.....with all that in place you'll have a compliant clutch that is easy and fun to drive.

 

LV_Ford_Fan

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Good points regrind the pivot ball, clutch stack height, etc. I said this in another post that the pivot ball height should be checked anytime you change flywheel and/or clutch package. I had the wrong release point happen to me and I did not like driving the car that way.
 

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