If you search around on the internet, you will find a lot of people that claim that the T56 can-NOT tow.Why they say this is beyond me, but I do have some theories.1. A bunch of computer chair mechanics and self professed experts are simply regurgitating what they have read some other jackass post on the web.2. Dodge stuffed the T56 in the SRT10 pickups but didn't give it a towing rating. AFAIK this SRT10 is the only production pickup-truck to use the T56.Regardless, this is an internet myth that needs to be debunked like the BS that it is.So I took my 1990 Silverado with my T56 from Guthrie, Oklahoma to Arkansas City, Kansas to pickup and bring back a longbed F150 for a friend.
I have not towed anything this heavy this far since the T56 swapI did several years back. My little 1/2 ton with a T56 towed the other truck and trailer with pure ease. Torque multiplication is the key if you're going to tow with a T56 (or anything for that matter).
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Mytorque multiplication comes in the form of 4.88 gears in my 14-bolt semi floater.Now I prefer to be very scientific and quantative, but unfortunately I did not get the opportunity to run the whole rig over a scale.I'm estimating the two trucks, plus the trailer, ramps, tools, etc. To easily be 10,000 LBS in total.With the 4.88 gears I was even able to keep the trans in 6th gear MOST of the time.
![Nv3500 vs t56 Nv3500 vs t56](/uploads/1/2/5/4/125446354/306065886.jpg)
I had to downshift into 5th to climb a few hills with all that weight, but all in all the truck performed like a beast.I drove up to Arkansas City with just my truck. In Arkansas City, we hooked up the trailer, loaded the F150 on the back, and headed back to Guthrie, OK. Round trip burned up 1/2 a tank of gas.
Not bad at all. Reviving this thread.I converted my 1998 4.2 V6 F150 to a 5.3 GM with a T56. The 4.2 expired even though it had less than 100,000 miles. 4.2s have intake manifold problems where water leaks into the motor causing hydrolock. I'm using an F car T56 now but asked a couple of reputable trans dealers about the T56 Magnum. I told them I might tow with it from time to time. Nothing huge.about 4000 maximum.
They couldn't say whether they would warranty the unit if it was damaged towing. 750ft/lbs of torque capacity seemed like a great feature but apparently towing is a different kind of stress. I get grief for having a hitch on my 'maro, and these cars were never given a tow rating higher than 2000 pounds. But the T5's weakness is mostly about 'powershifting', which truck guys can't do with those long shift levers.
In the mid '80s, the 300ZX turbo guys were breaking their T5s so much that Nissan took the 5 speed from the V6 Hardbody, gave it better ratios, and dropped the T5. The '95 Cobra R got the Tremec 3550 that should have been in all 5-liters since the 3550 was available in '87, as Ford was using other Tremecs in other regular-production F150s. So there's no debating that the T5 was a mistake. Better to put an OD in the tail of a Super T-10, but that never happened. The 'vette 4+3 was nearly as good, but costlier, heavier, weaker, and too complicated.
No good reason to use it in second or third as the 'vette did. But that was the Hone-O-Drive, which GM offered in the '66 Chevelle with the 283 and a 3.70:1. It would have done well with a 3.36:1.But towing is generally presumed, and usually correctly, to have no chance of breaking the tires loose on dry pavement, perhaps because of the tongue weight. 600-800 HP with 700 TQ in a car, most drag radials will spin before the trans breaks. But if the tires can't spin, something else will fail.Our cars can't tow enough to break a T56 Magnum, even on drag radials, no matter how much power you have, because the car itself will fail, one way or another.A T5 can take alot if you baby it, but then where's the fun? These cars are for driving, not babying.Likewise, why should Dodge put a tow rating on the SRT/10 pickup when they'd seen what people did with Chevy's 454SS sport truck?
Most never towed anything at all, and the few who did treated them like duallies, without incident. I once saw a 454SS towing a ginormous camper trailer, and it didn't seem out of control. Could SRT/10 buyers do much worse?It seems to me that many in the manual transmission industry like to reference how many millimeters between the input shaft center and the countershaft center. If we look at that, then the T56 and all variants since '93 are 85 mm. The New Venture 3500 and 3550HD are also 85 mm.
So by that reasoning, the T56 can tow as much as a NV3550HD.If we reference the traditional fact that taller ratios in first gear are stronger, the 3550HD is 3.49:1, the most common T56 is 2.66:1. So the T56 should tow more, once the axle ratio is corrected to make up the difference.Because I'm putting an '01 4.8L into my 'maro, I have all the info extant on '01 Silverados. The '01 4.8L / NV3500 combo, with the theoretically weaker 4.02:1 first, is rated to tow 8300 pounds, in a 2wd rcsb truck weighing around 4500 pounds.Most transmisions have a GCWR, but not those specific to sports cars only, like the T5, the ZF6-420 from the '90s 'vettes, etc.I always figured it reasonable to multiply the rated max input torque times the rated max GCWR, then divide by the actual weight for theoretical max power, or maybe divide by actual input torque for theoretical max GCWR?The difficulty with that is knowing your real torque. Weight is easy, it'll scale the same at any truck stop. Torque is affected by temperature, elevation, fuel quality, even humidity.And those ratings allow for some abuse. Except the T5, its ratings are optimistic even if you do baby it.
![Silverado Silverado](/uploads/1/2/5/4/125446354/237574642.jpg)
Well I got around to doing my T56 swap this weekend. Everything went pretty well aside from the fact that it was ridiculously hot out. The only problem I had was with the pilot bearing. My bearing from the 5 speed is the larger diameter bearing that fills the main hole on the crank.
It was in good shape so I left it in, I dont know what I was thinking. So I put the flywheel/clutch/pressure plate on, bellhousing and the trans input shaft hit the pilot bearing with about 1/4' to go, the input shaft is just a little longer on the T56 so you need the LS1 bearing, which I had but didnt put in the first time around. So I had to take it all off, knock out the bearing and install the smaller bearing in the second recessed hole.
Its my own fault but after that everything went fine. Had to flatten my Y-pipe just a little bit so it would fit under the rear section of the trans, and lengthen the VSS and backup light harness a little. Stock crossmember fit with no modification, reusing the trans mount from the 5 speed, stock 60e driveshaft is perfect length. Only had to trim the shifter hole about 1.5' or so with the front shift conversion. The forward and back throw is about the same as 5 speed but left and right throw is much shorter. Once I get the boot and stuff on it will look stock.Clutch bleeding went better than I expected.
I filled the reservoir and opened the bleeder and let fluid run out till it was clean and there weren't any bubbles. Then pumped the pedal a bunch of times making sure to keep the fluid topped off. Then opened the bleeder about 5 times or so when the pedal was all the way down and hardly any air came out just fluid, that was it. At first it was engaging about 1'off the floor but after about 30-40 pumps of the clutch with it running and a quick test drive it was almost back to normal. I still need to get my boot and stuff installed inside but thats the least of my worries right now.Heres a few pics.Difference in driveshaft length.
The T56 shaft is only a few inches shorter.Stock ClutchLS7 clutch on the left, stock on right.Stock NV3500 pilot bearingLS1 pilot bearing installed. I couldnt get the stock bearing pulled out, tried 2 different pullers with no luck so I just took the seal off and knocked the cage and. out and left the outer race in since there was enough clearance to put the input shaft through it.You have to knock out the pin on the LS1 slave and the truck line installs directly into it.LS7 clutch installed. QUOTE=zachmvery nice!
Sometimes i wish i had the luxury of a light weight single cab or even a 4th gen with a t56 just for the fun of banging through the gears. I think a couple people have already tried fully built t56's in heavy. ext cabs and the results werent pretty.just too much weight for the trans to handle.QUOTEI want to do a manual conversion to my 07 burb 2wd this winter.
T56 is a no-go, eh? I don't want to do a body lift for the nv4500 or the zf s6-650.
I plan on keepin the factory center console if possible and have the shifter come through where the cupholder is. Could it work to make a floor cutout and hide it under the console?