Towing with a T56? Possible?

This is for a '93 F150

One of the major changes I want to make to my truck is to turbo it.  To do this I'm likely going to need to get rid of the E4OD trans so I can run a homebrew EFI.  I've long wanted to put a T56 in the truck, but I'm concerned about towing.  I don't tow often, but when I do its my '67 Mustang, or a 14 foot fiberglass boat, so its not a heavy load.

Anyone know if the T56 will survive while towing?  Other thoughts to this experiment?

I wouldn't think twice about towing that boat with almost any vehicle, especially one with a transmission that can take the obscene HP and torque that the T56 does. 

For the Mustang, I guess the question is how heavy is the trailer? I would assume that it is fine though, but no data to back that up. 

I had the T56 in my SRT10 Ram and it towed decently well.  A fiberglass boat is no issues at all with that transmission. 

In reply to wearymicrobe :

I'd forgotten that those trucks had them in there stock.  I know they were initially rated at no load for towing (or something extremely low) did that ever change? 

The only concern with towing with a manual trans is excess wear from slipping the clutch from a stop.

You know that there are stand alone ECM's for that trans.  They sell then for folks that install them in older cars that didn't come with a computer controlled auto trans. Check out some of the aftermarket auto trans tuners. I did some research on this when I considered replacing my C6 trans in a van with a overdrive one.

I'm going to disagree a bit.

The T56 has kinda sucky ratios for towing.  First isn't that much higher than your current E4OD, but with an automatic that stalls at 2400, it is masked a bit.  Just swapping to a T56 loses the stall and raises first gear.  Not to mention, your double OD in the T56 will be completely useless.  You likely have 30" tires or so and 3.42 rear.  That puts highway cruise in 6th gear somewhere around 1200 rpms with the T56.

T56s match well in the ram with 4.10s.  In a pinch, 3.73, but not for towing.  You need final drive ratios in the 10.5 - 2.1 which you can't get without a axle gear swap.

Think of it this way... my Impala SS was going to get a T56.  Swapping from the 4L60E and 3.08s means that I would need 4.10s just to keep the same basic final drive ratio spread, and I would still have slightly lower highway RPMs.

You can get different ratios depending on which T56 you get, but keep in mind, the taller 1st is one of the reasons for the higher torque rating.  If you do the 2.90 first, it's only rated for 250 lb-ft.

Another thing about the Rams... they did not get the T56.  They got the magnum T6060 which is beefier in every single way.  Complete apples to oranges.  Different case, different gears, bearings, the works.

It's also not just about torque capacity.  A transmission behind 350 lb-ft is completely different if you're at curb weight versus max GCVW.  The T56 will get very hot while towing.

I hate to be a downer, but in my opinion the T56 is the worst possible choice.  High buy-in, terrible ratios, not up to the task.  At all.  Great performance box, terrible towing box.  Heck, I'd be concerned about it with the turbo and no trailer at all.  GCVWR for T56s is remarkably low.  Borg Warner used to rate them at 6000.  A trans at it's max torque and 6000 lbs is a far cry from a trans at max torque and 12,000 lbs.

TL;DR, using torque rating to determine if a trans is up to the task of towing is not a valid metric.  Look at it's GCVWR.  Is it possible?  Yes.  But you'll be unhappy with it's ratios, and you'll be really unhappy when you're picking up pieces of your t56 off the highway.

Ever notice how truck manual transmissions like the NV5600 are stubby but tall?  It's because of the diameter of the gears.  You need that radius to transmit torque without blowing stuff up.

In reply to jimbbski :

I remember looking at Baumann controllers a long while back.  I just wasn't that interested.  If I'm doing that work I'd rather have the manual.

In reply to Curtis73 :

I might not have been clear enough.  I want the truck to drive as a daily, as that's what she is now.  However semi-randomly I need to do something like move a car.  95% of the time the car I need to move is my Mustang, at most that towing is maybe 4 hours on the road every year or year and a half.  Its a very low amount of time towing, compared to actual driving.  Still, if there's a better option for a trans, I'd be glad to look at it.

Rear end will definitely need to be done as well, 29" tires (I believe) and its 3.00 gears back there, puts it right at 2000-ish RPMs at 70.  I was hoping to drop that down to at least 1500RPMs cruising

Mr_Asa said:

In reply to jimbbski :

I remember looking at Baumann controllers a long while back.  I just wasn't that interested.  If I'm doing that work I'd rather have the manual.

MegaSquirt to the (potential) rescue!

https://www.diyautotune.com/shop/transmission-vvt-control/microsquirt-transmission-controller/

add another to manage your EFI bits and connect via CAN.

Done.

T56 gearing is shallow. I didn't enjoy driving a car with a Cobra T56 and 3.07 gears because it idled so fast. Maybe go for the factory manual trans? M50DR2 or a ZF S5.

In reply to Curtis73 :

The SRT Rams defiantly had the T56. The 6060 is a common upgrade though on the single cabs. 

Borg Warner originally designed the T56 as a truck transmission, it was first used in the Viper because it was the only domestically produced transmission that could handle the torque. The Viper was too low volume to consider the ZF 6 speed that the ZR-1 used.

The Chevrolet SSR pre-'05 had a 3.01 First gear and I believe some of the newer V8 Camaros also offer a 3.01 First gear. It's not much, but with a 4.10 or 4.56 you could haul stuff and still have really decent fuel economy in 5th/6th gear, but you'll need a torquey motor to tow in OD.

Mr_Asa said:

In reply to Curtis73 :

I might not have been clear enough.  I want the truck to drive as a daily, as that's what she is now.  However semi-randomly I need to do something like move a car.  95% of the time the car I need to move is my Mustang, at most that towing is maybe 4 hours on the road every year or year and a half.  Its a very low amount of time towing, compared to actual driving.  Still, if there's a better option for a trans, I'd be glad to look at it.

Rear end will definitely need to be done as well, 29" tires (I believe) and its 3.00 gears back there, puts it right at 2000-ish RPMs at 70.  I was hoping to drop that down to at least 1500RPMs cruising

I looked through and didn't see what engine it was.  300? 302? 351?  1500 rpms cruising is a bit low for me, but it could work.  Best MPG and piston temps will happen at about 80-90% of your peak torque RPM.  So if your torque peaks at 2000, 1800 would be great.  Less isn't better, but I'll leave that to your discretion.

If you're really towing that infrequently, it might do the trick.  I prefer overkill so I don't have to baby things, and with the wide variety of good options out there that don't cost three arms and two legs, I personally would look elsewhere.

M5R2 is a bolt-in swap, great ratios, and they get a bad rep for stupid reasons.  Mazda made them with rubber plugs shoved in the holes for the shift rails.  They like to fall out and splash lube out which obviously kills them.  The fix is stoopid simple.  Silicone the plugs in.  Or if you want to get fancy, use a freeze plug hammered in.  Or if you want to go full metal jacket, drill and tap for NPT plugs.  Bad rep = cheap.  Truth is, they're a great transmission.  Pair it up with some 3.73s and the OD will keep you around 2000 at cruise.

There are a ton of other options out there, but none that easy.  ZF did an S5-42 for behind the early Powerstroke trucks, but you'll have to contend with the big-block bellhousing pattern, and the bellhousing is cast integral with the case.  It has been done with adapters plenty of times.

I know this isn't the route you were thinking, but with a wide torque curve like you probably have, NP435.  Yes, it's only a 4 speed, but it would be perfect... and no need to swap your rear.

The only one I would think is better than the M5R2 would be the TR-4050.  Again, not an easy swap, but it can be done.  They used the 4050 in jeeps and chevys, but only in Fords in other markets (south america, rumors of Canada) in the superduty trucks, but not the diesel, so there is a good chance of finding one (with the big wallet) with your bellhousing pattern.

But honestly... easy button... M5R2.

buzzboy said:

T56 gearing is shallow. I didn't enjoy driving a car with a Cobra T56 and 3.07 gears because it idled so fast. Maybe go for the factory manual trans? M50DR2 or a ZF S5.

Quoted for truth.

If you really want the wow-factor of 6 gears, the T56 will get the wow factor, but have a ton of drawbacks in a towing/truck application.

Curtis73 said:

I looked through and didn't see what engine it was.  300? 302? 351?  1500 rpms cruising is a bit low for me, but it could work.  Best MPG and piston temps will happen at about 80-90% of your peak torque RPM.  So if your torque peaks at 2000, 1800 would be great.  Less isn't better, but I'll leave that to your discretion.

Its a 300, so there isn't really a peak torque, which is one of the huge things I like about this truck.  Throwing a turbo on will change that, but I will be planning to keep as much of the truck characteristics of it as possible.

Part of wanting the 6-speed was to match the 6 cylinder, sort of as an aesthetic thing.  Wanting a nice low OD in order to boost the rear end gear was a plan as well, though.

The M5R2 has a pretty low towing capacity. For example, a 97-03 4.2 truck with the M5R2 is rated at 2,000 lbs towing. The same truck with the same engine and the 4R70W auto has a 4,700 lb towing capacity. Step up to the V8 and a 4.6 truck with the M5R2 only has a 3,500 lb tow rating.

In terms of RPMs: My LS1 Camaro with the T56, 3.42 gears and 315/35-17 rear tires turns 1300 rpm at 65 mph.

In reply to Will :

The M5R2 is not the limiting factor in that truck, it's the 4.2L, and I'm not sure where you're getting the 2000 lb rating.  The lowest rating was 5000 in the Lightning and the rest range from 6900 to 8300. I had a 99 F150 with the 4.6L and M5 and it was rated at 5500. Heck, even the M5R1 in rangers has as much as 5500 lb tow ratings.

1300 RPMs in your camaro isn't terrible.  The LS has enough torque down there and it's not trying to push a heavy brick of a truck through the air with half the torque like his 300 has.  Part of the reason they gear the F-body that way is so the pinion doesn't eject the diff through the cover with malice.

If Mr_Asa wants the real deal, can't-be-killed, master of all 6 speeds, he needs an NV5600.

I'll stand by my recommendation.  The whole T56 is a close-ratio box designed for light GCVW.  The M5OD is purpose-built as a light truck transmission.  Not heavy duty by any means, but it will certainly last longer and have better ratios than the T56.

Keep in mind that transmissions are rated not just by the physical transmission.  Example:  The TNET1247 in the Viper was rated for 550 lb-ft.  The Camaro version was rated for 450.  All over the market the exact same part numbers used for gears, center case, shafts, bearings, shift forks, etc could have been rated as low as 330 lb ft despite being the same exact gearbox and guts.  This was partly based on vehicle weights, rear axle ratio, etc.  Put the same transmission in a Locost and a Ram pickup.  In the Locost it could survive with 700 lb-ft.  In the Ram, maybe 450.

When it comes to manual transmissions, the GCVWR has the greatest impact on its torque capacity.

In reply to Curtis73 :

I was using the specs here: https://www.fordf150.net/specs/02f150.php

Now, if it's not accurate, it's not accurate. The site claims it's from a Ford press release, but I can't say one way or another.

I see what you're talking about.  Over at another part of that same site it shows towing with a manual at anywhere from 6900-7200, but it's vastly different between the XLT and the Lariat.

Confusing to say the least.

So we've narrowed it down to somewhere between 2000 and 8000.  :)

Suffice it to say, I have owned two trucks with the M5 (one an R1 in a B4000 and the other an R2 in an F150) and both were rated at 5500 in the 2wd.  My B4000 is a 4wd, so they dropped it down to 3700 for some reason.  Suspension maybe?  I could understand a 500lb difference, but not almost 2000.  Anywho... I don't think the M5OD was the reason for a low tow rating.  Certainly lower than the automatic which is almost always the case, but there are plenty of configurations with the M5 where tow ratings are much higher than 2000... indicating that it isn't the reason for the low rating.

^Sometimes it takes the Bloodhound Gang to figure out that E36 M3