If you’ve seen the tow ratings for Mazda trans equipped trucks, even Ford piles on. Ford isn’t doing that (being conservative with ratings) for warranty purposes, either, as clutches are wear items. There was a lot of coping years back when folks bought 5-speed F150s to tow and everyone parroted that reasoning (warranty!) for the low ratings.

 

I dont know how much the trailer weighed, but my aunt and uncle pulled a horse trailer with their m5od equipped f150. From Montana to South Carolina with 3 horses in the trailer, sold those 3 and bought 2 younger ones. Then made the trip back to Illinois before having the trans run dry because they had the top cover leaking and didnt fill it. So we put a junkyard m5od in and made sure it didnt leak. They pulled that trailer for 6 more years after that. So yes the Mazda can tow, but it's got to be filled and checked regularly.

 

And exactly how many have you seen broken from over loading? I've seen at least a dozen examples over the years hold up to more abuse than they should have. Heck there was a guy who swapped one into an F350 (5.8L) and ran it for years without issue. I'm not saying it's the greatest trans in the world - far from it. But it's not some fragile glass egg either. It is what it is - a perfectly useable transmission with a nice gear spread that shifts relatively decent as far as truck transmissions go and is capable of holding up to the duty cycle reasonably associated with a half ton pickup.

FWIW I've been inside both the M5OD and ZF and yeah, the ZF has bigger parts, but not by as much as you'd think. The input shaft is probably limiting on both and the smallblock versions happen to have the same diameter and spline count. Rev up a strong 351 and dump the clutch with sticky tires on sticky pavement and you'd probably snap the input off of each. To me, the ratio in first gear is the biggest difference between the two when discussing a half-ton application.

The common failure modes for the M5OD are loss of lubrication due to leakage from the rubber shift rail plugs and worn or broken shift forks due the driver leaving his/her hand leaning on the stick while driving in gear. Both are independent of load. The fork issue happens to ZFs as well.

Also, Ford always rated the manuals lower, even back in the 70s when the indestructible cast iron T18 or NP435 were the most common transmission in those trucks. This is primarily due to manuals are harder on the downstream drivetrain due to no big rubber band (torque converter) in between the engine and trans to absorb shock loads caused by the dummy behind the wheel.

 

After reading some more threads. It sounds like the zf42 is going to be better with the 3.55 gearing in my truck. What are your opinons?

 

Like I said earlier, you'll probably like the deep 1st gear of the ZF better if you're towing a 4000 lb trailer often. That 1st gear makes it so much easier on the clutch when starting from a dead stop.

 

Yes the deep 1st will help. I have pulled stupid weight a couple times with my 5.0 m5od 3.55 truck... but yes the M5 first made it tricky to get moving initially. However, once rolling 3 or 4 mph you can clutch out fully and go.
The most I pulled was a dead 7.3 crewcab 2002 super duty hitched to a tandem axle dump trailer loaded with 25 square of roofing material debris.

Idk how much it weight but would guess close to 12000 (edit add my truck weight and it was probably closer to 17000) total. Now I only went 25 to 30mph for the 5 mile trip, but like I said once rolling it pulled just fine. Stopping was fine since we used the trailer brakes and the super duty brakes to stop the nightmare train lol

 

Sorry guys forgot to include this info. I was trying to figure out if the zf s5-42 or the zf s5-47 would be better for a truck with 3.55 gearing. I know the -47 are harder to find but as far as towing are they better? What about higher speeds like on the Interstate?

 

Also,

What about a new drive shaft?
My truck is a extended cab short bed 4x4. If I was to find an f250 or 350 that was an extended cab short bed 4x4 with the zf-s5-42 or 47 would that drive shaft work? Or No?

 

Both transmissions have the same ratios. Your “higher speed” rpm question was answered in post #7. The ZF5 has a .76 overdrive and the e4od is .71. You won’t notice the difference.

 

What makes them different?

 

The -42 and -47 are essentially the same transmission, the -47 has some very minor internal improvements that barely even matter on a high-GVWR diesel application. There's no functional difference between the two for your small block 1/2-ton application. For the smallblock version that fits your engine, the -42 and -47 have the same ratios. Go with whichever one you can find first.

You'll have to get the driveshaft lengths adjusted at a driveshaft shop. The F250/350 shaft will be too short because the 10.25 sterling rear axle in the 250/350 has more pinion depth than the Ford 8.8 rear end in your F150.

Ratios are as follows:

Trans, 1st, 2nd, 3rd, 4th, 5th, Reverse
E4OD, 2.71:1, 1.54:1, 1.00:1, 0.71:1, ----, 2.18:1
M5OD, 3.90:1, 2.25:1, 1.49:1 1.00:1, 0.80:1, 3.39:1
ZF S5-42/47: 5.72:1, 2.94:1, 1.61:1, 1.00:1, 0.76:1, 5.24:1

So in 5th on the highway, the M5 will run 12.7% more rpm than the E4 and the ZF will run 7% more rpm than the E4. Keep in mind that the automatics get away with numerically lower 1st and reverse ratios because the torque converter does a lot of torque multiplication at low speeds.

 

from what I could find is a updated case design makes the 47 stronger. There is a diesel version and gas version, the ratios differ between those but for the gasser they are the same.

 

Thanks for the ratios. That helps. So either one will work being almost identical.

 

So if I go to my local junkyard and find a zf 42 or 47 how do I know that it is evenin good shape? What should I look for?

Also,

Will my existing transfer case be able to handle the new tansmission?

 

You won’t unless you heard it run and shifted it.

Yes.