T56 Nightmare, need help

[JLTH2183]

So even after running a dedicated switched power to the engine fuse panel box and a dedicated ground straight to the negative battery cable terminal the car still dies when put in reverse.... you know what fixed it???? Installing the old tune!!! Apparently the new tune revision I received is FBS! I could of been driving my car 3 days ago.
Going to be making a phone call on Monday. Until then I'll have to see how she drives and put 600 miles on the new clutch before I can really see what she can do.

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[Ruiner46]

The reverse thing is weird and I don't know how the tune could be making the car die when you put it in reverse. Does it die as soon as you shift into reverse, or is it when you start to move in reverse?

Rev hang and cruise not working are because the tune is not setup right for the T56 gear ratios.

The speedo being off is probably your imagination, or you just now noticed it because the speedo comes from a wheel sensor and is not related to the transmission.

One side note, if you get a competent tuner and don't use the reverse lock out... you really don't need the Bowler harness. I mention that because if the car dies right when you shift into reverse, that sounds like some kind of short in the Bowler harness wiring.

 

[JLTH2183]

The reverse thing is weird and I don't know how the tune could be making the car die when you put it in reverse. Does it die as soon as you shift into reverse, or is it when you start to move in reverse?

Rev hang and cruise not working are because the tune is not setup right for the T56 gear ratios.

The speedo being off is probably your imagination, or you just now noticed it because the speedo comes from a wheel sensor and is not related to the transmission.

One side note, if you get a competent tuner and don't use the reverse lock out... you really don't need the Bowler harness. I mention that because if the car dies right when you shift into reverse, that sounds like some kind of short in the Bowler harness wiring.

It was 100% the tune. Car would not even attempt to start when put in reverse before hitting start button. I could start the car in neutral with clutch pedal down but as soon as I moved shifter into reverse it would die without letting clutch pedal out. Spoke with Bowler and they said all my wiring was correct but to run dedicated switched power and ground and there was no change. Installed old tune and I no longer have the problem. Just using various different GPS navigation apps and I'm about 5 mph off from actual speedometer. I installed new tune revision tonight and no longer have the engine stall when put into reverse and the Rev hang seems to be fixed but now when I come to a complete stop the idle goes down to 500 RPM and the engine almost stalls.

 

[Unas2k5]

Wow sounds like a nightmare. I would have it towed to a shop at this point. Id rather pay $900 for a trans install than go thru all of that. Good luck . Hopefully you have it figured out soon.

 

[Grimreaper]

Im sorry. Crappy feeling to have for so much work and money put in. Reminds of having to pull a 7m out after fresh rebuild and several month wait years back. Gas and matches becoming tempting.

What motor mounts? Is there an actual bushing in the trans cross member/ mount?

 

[JLTH2183]

Im sorry. Crappy feeling to have for so much work and money put in. Reminds of having to pull a 7m out after fresh rebuild and several month wait years back. Gas and matches becoming tempting.

What motor mounts? Is there an actual bushing in the trans cross member/ mount?

I had to lower the engine 1/2 inch even though VMP advertised ODIN would clear the stock hood but it rubbed. There Steeda adjustable motor mounts. I may adjust them and raise another 1/4 inch and see if the blower doesn't make contact then. I wish there was a way for me to measure the distance between the blower and the hood when closed. Maybe I'll use some butyl chord and cut 1/2" and 1/4" sections and close the hood to see if it makes contact or measure how much the butyl compresses down... problem is it tends to be sticky so when I raise the hood it may stretch back the opposite way so then I will have no accurate measurement.

There is an actual bushing in the rear Trans mount that was provided with the T56

 

[Rod Schneider]

Use Play Dough instead of butyl chord, it's not near as sticky!

 

[JLTH2183]

Use Play Dough instead of butyl chord, it's not near as sticky!

Thank you I'll go that route

 

[Angrey]

So wait, you didn't index the bell housing?

A friend of mine just had his Magnum installed and JPC (where he bought his) told him it didn't need to be indexed (that they somehow index them against a "standard" block. I found that sketchy. Bowler, Modern Driveline, both great shops that I dealt with for part of my setup highly recommend at the very least checking it for concentricity (preferably for both concentricity AND parallel).

I didn't end up needing any offsets, but I know a bunch of people that do. Maybe these shops CAN check it against a block before sending it out, my question is, what do they do when it doesn't run out within tolerance? Without offset dowels, how do they make the necessary adjustment to center the input shaft/trans onto the bellhousing (which is dictated by the fasteners on the block).

Whether it's horror stories and exaggeration, every reputable shop claims that bad concentricity will result in everything from excessively and prematurely worn out pilot bearings to poor shift performance at high rpm. I'm not sure that bad runout is causing your NVH, but if you are pulling the trans again, I'd take the time to check the centering.

Other than clutch chatter with my Tilton at low/lugging conditions I do not get any bad or excessive NVH. (I'm running a Steeda TriAx, which for all intents and purposes is very similar or identical to an MGW short throw direct shifter (or any other)). Have you tried swapping the MGW for the Tremec shifter? The NVH you're referencing, are you sure it's not just clutch chatter?

 

[J17GT]

What model RXT did you go with? If it’s a solid hub version, what you may be hearing while lugging around at low RPMs is called ‘gear rollover.’ That gear rattle sound will come up through the shifter. I used the GT500 sprung hub RXT with my Magnum swap and the trans is silent.

What driveshaft do you have in it? I have an aluminum Dynotech with billet yokes. I do get some driveline vibration above 70mph on deceleration. I need to go back and rotate the driveshaft around to different positions to see if it improves. Just have not felt like doing it as I don’t drive on the highway much.

I have Kooks longtubes and the fitment is perfect. Actually did them after the Magnum swap. Sounds like some of your vibrations could be related to the LTH fitment…which sucks.

Regarding shift quality.…I agree it is not as great as I thought it would be. I have 2000 mostly city miles on my setup and I’d call the shift quality just OK at best. It did get a bit better with some mileage, but I would never call it great. I will say though, when you beat on it and shift from the moon, it’s like the gates are WIDE OPEN. Goes into each gear like butter. The last time at the track I was power shifting at 8000rpms and it never missed a beat. I also think a dual disc clutch disengages better with RPM. It‘s like the entire setup just prefers you beat on it rather than drive slow and easy.

I did not index my bellhousing either. The tremec manual even says if you have your stock factory block in the car, no need to do it. In hindsight, I wish I would have. Would the shift quality improve, maybe? If this trans ever has to come out again, I will do it then.

My biggest challenge was for some reason I required a shim behind my slave. I blew the slave out on the second WOT shift after the 500 mile break-in. Talk about taking the wind out of your sails… I worked with McLeod and determined after some measurements that I needed a .450” shim behind the slave. Did that and no more issues with the slave. I was hoping maybe the shift quality would improve as well, but it did not change.

I know the frustration, but hang in there. Remember it’s a big beefy trans, so it won’t ever feel like your made of glass MT82.

 

[JLTH2183]

I finally had time today to remove my T56 XL, the clutch and the bell housing. After reinstalling the bell housing, I checked bell housing parallelism and I'm reading anywhere from .001 to .005 which is within specs. When indexing the bell housing I'm reading - .006 on left marking and - .005 on my right marking which is well within specs from side to side. My bottom mark or starting point is 0. My top mark is reading -.0082 so when I divide that by 2 that gives me .0041 so I'm within the .005 tolerance so I do not need offset dowel pins correct? I used 2 different dial indicators and had a friend turn the engine over multiple times so I could confirm the same readings over and over again.

 

[Grimreaper]

What was the final out come op? Rag in the gas tank or the t56 finally prove itself?

 

[mitsuchris]

ugh I just read through your post. rough situation. hopefully when you send the t56 out they find issues with it. this is the route I was going to take in the future. luckily my mt82 is ok at this time. you definitely need a daily driver to fall back on. making the daily a racecarr is a rough road.

 

[Ruiner46]

FWIW, I had trouble with the Mcleod RXT clutch for the T56. My unit, when combined with the Mcleod flywheel was way out of balance and I had to take it to a shop to have every part of the clutch balanced individually and then as an assembly with the flywheel. I had a ton of shifter rattle that got worse with RPM until it was balanced. Another member here also had trouble with the slave cylinder spacing and had to machine a pretty large shim. I didn't have that problem at all, but my T56 was pretty notchy for the first 1500 miles or so. I never did have any trouble shifting into the higher gears... 4th/5th/6th were always smooth. My trouble was more in the 1st/2nd gears and that has smoothed out a lot with time. It's still a little notchy when cold, but I think that's pretty normal.

 

[Angrey]

Man, you've been hit with the whole menu. I think part of the problem may be that there are multiple issues going on simultaneously.

First, yes, the tune plays a part (from rev hang to torque tables, as crazy as it sounds, if the tune isn't proper, it has way too many nanny features and protections to try to save the drivetrain from abuse).

Second, shift quality. There's a ton of debates and discussions about what fluid to run and like most things, there's no magic bullet. Tremec features both advanced and non-advanced synchros. Apparently a bunch of GM complaints caused them to swap synchro types on the first two gears to improve low temp shift engagement. I'll spare you the pages and pages but ultimately, if you want cold shift quality, you're going to expose the trans to wear and tear under high temp. If you want high temp protection, low temp shifting/engagement is going to suffer. I trust a couple of well known track rats over on trackmustangonline who tried every combination available and settled on motorcraft DCT with a friction modifer added as the best combination of temps and shift engagement. If you dig deep down into some of the discussions, even Calimer admits now that the infamous Calimer cocktail isn't the best fluid for harsh/track purposes. A lot of shops will outright dog cuss Royal Purple.

Also getting a vote in shift engagement and quality is the clutch and the alignment. It seems like you've resolved that it's not an alignment problem, so you may be getting clutch engagement issues that are contributing to shitty shifts. The bearing and dimensions (all of them, the gap, the length of throw) ALL contribute to whether or not a clutch properly disengages the input torque and therefore allows you and your synchros to easily engage the next set of gears. If that process is even SLIGHTLY muddled, you're going to be fighting to get into gears AND ultimately it's going to wear out your rings and synchros faster.

Like stated above, there are few magic bullets when it comes to clutches. If you want it to hold an ass load of torque, if you don't want 100 lbs of clutch force on the pedal, if you want it to LAST and wear well, if you want it to engage smoothly without grabbing, if you don't want it to chatter at low rpms and if you don't want it to cost a small fortune, those are ALL things that compete and oppose each other in different combos. Triple discs are better than twin discs are better than single discs. Clutch material gets a vote as does the overall design, flywheel material and heft, etc.

It sounds like you're not getting full disengagement of the clutch in between shifts. This is one of the advantages of the Tilton bearing over others. You can custom set/adjust the throw length. With the other OE style bearings, you can do that but with spacers/shims. Again, you want it to disengage fully, but you also want it to engage fully when depressed. There's an optimal range/dimension.

It's not unthinkable that Tremec has defects, but I'd say the odds of that are very VERY small. If you've lined it all up properly, chances are, it's either your fluid, your clutch, or both. I highly doubt it's a shifter issue given that they're all basically the same design. The only differences being springs and feel (notchiness).

I have things I don't like about my Tilton clutch. It's very grabby and continually tries to embarass and stall me coming from a stop in 1st. But after that it's perfectly fine. It does chatter if I lug the car in a high gear and don't have the music on, but that goes away above 3k rpms or so. I run a trans cooler so I keep the temps within a pretty tight range that works well with my fluid.

Unfortunately you may be dealing with a lot of different factors and it's hard to isolate the problem sometimes if that's the case.

I know it's been a rough road, but at the end of the day, a properly functioning stout trans with a tail section is much MUCH better than a short trans (even a TR6060). You won't have to deal with all the problems of critical speed and 1/2 critical speed of a really long driveshaft. Shifting is infinitely better with a direct mount.

Keep at it, you'll get there (maybe with some of your hair left).

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