M50D – Weak Link when towing with a Ranger?

[Kage]

Cliffs: Considering using my wheeler to tow a ‘light’ (Sub 4k) Pop Up/Travel Trailer to local wheeling spots. My concern is whether or not the M50D will hold up to the weight I’m moving.

Build Thread Background (link)

Going by the factory specs on my truck, it was rated for 7,000 lbs combined vehicle weight. (’94 Super Cab, 4x4, 3.73’s, 4.0, M50D, 30” tires).

The truck has grown up a little bit from the factory specs, as it sits right now:
- 8 Lug Dana 44 (‘78 Twin Piston F-350 brakes)
- FF Dana 60 Rear from an E-350 (again Twin piston Disc setup)
- 4:10’s (going to be 4.88 in the near future)
- 37’ Nitto’s
- Wheel base set to 115” (about 10” shorter than factory).

As it sits in ‘street trim’ it weighs in at 5,400 lbs which means I’ve got 1,600 lbs capacity left over from the factory setup. However, I’m not really sitting at factory specs anymore.

With the upgraded brakes, I’m not worried about stopping any (reasonable) additional load that I’d put on this truck as they are true 1 ton brakes. I am worried about the rest of the drive line though, mainly the M50D. So my primary question is…

Do I need to be worried about loading the M50D this heavy? (about 1,400 – 2,400 over what the ‘factory’ rating is).

I’ve not played with these tranny’s too much, but as light as the thing feels, I’m a little concerned with melting it down trying to pull anything with this setup. Is my fear justified, or just rock on?

 

[RangerSVT]

I dont think it be too bad on it...I have a 96 ranger 2.3L with the M5OD and I towed a 99 4x4 explorer from new york to tn with no problems, 5 years later, still running like a top, doesnt come out of gear, doesn't grind going into any gears, no howling noises (signs of bearing wear)...All is good....Hmm, interested in a better gear ratio for you M5OD??
SVT

 

[bobbywalter]

with dual t case off road its a non issue.

with 37 in tires the minimum, 4.88 gears at least imo...for a driver anyway.



for now though, run an hd clutch and get it.

or just get it.

with a normal clutch and proper maintenance i think you will be just fine really. and the clutch will be the weak link.

 

[Hahnsb2]

Just keep it out of 5th.

 

[4x4junkie]

4.88 is a tad tall for 37" tires (5.13 would be better).

I think you'll be OK, though you'll probably want to keep it out of overdrive (5th) while towing (some say you should do that anyway, though if your axle gears are well-matched to your tires, there most likely would be no issue with it).

 

[strvger]

or you could go with a light weight, all aluminum camper. i have one and it's great. best part besides the light weight is no wood to rot and the only steel is the axle... no rust! certainly worth taking a look at:

http://www.livinlite.com/index.php

i have the 6.0 and can't even tell it's behind my 1st gen with the 2.8. and at only about 600# and with my 4.56 gears, i can even use 5th on straight to mildly hilly roads without straining the motor (or tranny) at all.

 

[Kage]

I dont think it be too bad on it...I have a 96 ranger 2.3L with the M5OD and I towed a 99 4x4 explorer from new york to tn with no problems, 5 years later, still running like a top, doesnt come out of gear, doesn't grind going into any gears, no howling noises (signs of bearing wear)...All is good....Hmm, interested in a better gear ratio for you M5OD??
SVT

Thanks, The "4 banger gear swap" is on my list of wants for this truck.

with dual t case off road its a non issue.

with 37 in tires the minimum, 4.88 gears at least imo...for a driver anyway.

for now though, run an hd clutch and get it.

or just get it.

with a normal clutch and proper maintenance i think you will be just fine really. and the clutch will be the weak link.

The clutch is fresh (3k miles on it at this point). I'm not really worried about towing offroad, as there aren't any 'remote' places out here to drag a camper to.

Right now with the 4:10's its not to bad at all to drive around in. Either a 4.56 gear swap, or dumping the 4 banger gears into the tranny (or both) would make it ideal for what I use it for. Keep in mind that I live in the flat lands

That said, if I'm going to go through the effort of a gear swap, 4.88's it'll be

Just keep it out of 5th.

Why? Can you elaborate a bit more than that?

4.88 is a tad tall for 37" tires (5.13 would be better)...

5.13's are a bit too much gear for my taste. 4.88's put me at ~2500 rpm's at 70 mph wich is my usual cruising speed. And to be honest, I don't like spinning the motor that fast as it seems to be much happier around the 2200 mark (4.56's)

...I think you'll be OK, though you'll probably want to keep it out of overdrive (5th) while towing (some say you should do that anyway, though if your axle gears are well-matched to your tires, there most likely would be no issue with it).

I'm not so sure why people are afraid of running in 5th? Does the OD gear get starved for oil or something?

or you could go with a light weight, all aluminum camper. i have one and it's great. best part besides the light weight is no wood to rot and the only steel is the axle... no rust! certainly worth taking a look at:

http://www.livinlite.com/index.php

i have the 6.0 and can't even tell it's behind my 1st gen with the 2.8. and at only about 600# and with my 4.56 gears, i can even use 5th on straight to mildly hilly roads without straining the motor (or tranny) at all.

Those are some slick trailers!


Thanks for the comments guys, you're making me feel better about considering towing with this truck. As of right now, I'm in research mode for what would be the best 'fit' for what we want to do moving forward. The main optoins being:

1) Going the truck camper route (would need to buy a truck ) and that truck would wind up being my DD, so this option isn't the best.

2) Buying a smaller Travel Trailer/Pop up that I can tow with this truck. The bonus here is that not only could we use it on vacation (thus making them cheaper), but I can use it on my 4wd trips. Which would be awesome as I'm tired of tent camping!

3) Hitting the lottery and buying a bus (Guess I need to start buying tickets)

I'm thinking that I shouldn't count on option 3...

 

[Tractorman]

Well, yes, the upgraded the hardware on your truck helps you out in every way, except on how it sits legally.

People say stay out of fifth because its the weakest gear set.

Shorter wheelbase is counter productive to a positive towing feel, but for as little weight as you're thinking of towing it shouldn't be bad.

 

[Kage]

Well, yes, the upgraded the hardware on your truck helps you out in every way, except on how it sits legally...

Agreed, but since I'm "overweight" as the truck sits empty, I might as well go for the gusto

Not trying to get into a 'legal' pissing match, in IL's eyes, as long as I'm not exceeding my tag weight (8k lbs) life should be good. So long as what I'm doing doesn't look sketchy in the State Toopers eyes, I should be ok.

Keeping things legal is definetly on my mind though.

...People say stay out of fifth because its the weakest gear set...

Kinda what I figured, but I was hoping for some hard numbers/experiences. There appear to be lots of claims of "Stay out of 5th, its weak!" But I haven't found an example of a failed gearset. I'm not saying they aren't out there, I just haven't run across one yet

FWIW, I would think that when using common sense, life should be fine (Not lugging the thing around in 5th gear for example).

...Shorter wheelbase is counter productive to a positive towing feel, but for as little weight as you're thinking of towing it shouldn't be bad.

Yup, I realize I went backwards (In regards to towing) with the shorter wheel base. But 115" isn't exactly short either.


Thanks for the comments!

 

[RangerSVT]

Only reason why I wasnt in 5th (except for flat ground) was for the gear reduction, OD was a little too much for the gerbils under my hood, they liked 4th gear much better for the hills and downgrades, but I had no problems pulling in 5th gear...
SVT

 

[Captain Ledd]

5th gear is fine unless you find yourself putting a ton of power through it. If it needs too much pedal, downshift.

 

[4x4junkie]

5.13's are a bit too much gear for my taste. 4.88's put me at ~2500 rpm's at 70 mph wich is my usual cruising speed. And to be honest, I don't like spinning the motor that fast as it seems to be much happier around the 2200 mark (4.56's)

2500 RPM is actually right about the 4.0L's sweet spot for cruising.

I'm not quite sure where you got your figures from, but with 5.13s and 37" tires, you should be right about 2400RPM in 5th gear @ 65 MPH (or ~2580 @70) The 4-cyl gears in your M5OD doesn't change this at all, 5th (OD) is the same ratio either way (0.79:1). 4.88 is going to miss that mark by a fairly good margin.

And yes, 5th tends to be the most vulnerable gear in a transmission not so much because it's weaker, but because it typically sustains the most load of any gear, which creates more heat in the transmission as well (towing would aggravate this even more). A deeper axle gear (5.13) will take a good portion of the load off the transmission, which should help it last longer (not as much heat generated).

If you still insist on going with 4.88s, then I would again recommend you stay out of 5th completely while towing.

 

[Kage]

5th gear is fine unless you find yourself putting a ton of power through it. If it needs too much pedal, downshift.

That's pretty much where my head is at

2500 RPM is actually right about the 4.0L's sweet spot for cruising.

Personal preference here. Yes the torque curve is at 2,400 rpms on a OHV 4.0, but mine seems to be happier at 2,000- 2,200 revs. YMMV.

...I'm not quite sure where you got your figures from, but with 5.13s and 37" tires, you should be right about 2400RPM in 5th gear @ 65 MPH (or ~2580 @70) The 4-cyl gears in your M5OD doesn't change this at all, 5th (OD) is the same ratio either way (0.79:1). 4.88 is going to miss that mark by a fairly good margin.

The Grimm Jeeper (Link) Website has an awesome (and accurate) calculator to play with. But we can simplify it a bit more by cross multiplying and dividing (and ignoring the extra vehicle weight):

Tire 1 = Org Gear Set
----- = --------------
Tire 2 = Needed Gear Set

So that:

30” = 3.73
--- = ------
37” = xxxx

X = 4.60 (or 4.56’s) which would put right back to the “Stock” rpms on the high way (about 2,200 ish). With 4.88’s that puts me about 2,450 ish rpms at 70 mph. 5.13’s will run around 2,570 rpms. So we’re talking about ~100 rpm difference on the highway between 5.13’s and 4.88’s.

This is all assuming that my 37’s actually measure 37” when in truth they’re closer to 35” tall. I’m not refuting your numbers, just giving you an idea where my heads at.

The 4 banger gears are just a thought to help get things rolling (from a stop). I know they still have the same OD ratio and if I could have my way, I'd love to have an ulta low granny gear to get things off the line. Something ala the NP435 low.

In all honesty, I actually like the 4:10’s I have in the truck now for crusing down the road, my complaint is the ‘effort’ it takes to get this rig rolling when loaded, and really 4.56’s with the 4 banger gear set in the M5OD would keep me quite happy. But I don’t want to spend the money/effort on regearing one step (Keeping towing out of the equation).

You’ve also got to keep in mind, I live in the flat lands, so I don’t really need the deep gearing that you folks out west need to get up the mountains out there.

......And yes, 5th tends to be the most vulnerable gear in a transmission not so much because it's weaker, but because it typically sustains the most load of any gear, which creates more heat in the transmission as well (towing would aggravate this even more). A deeper axle gear (5.13) will take a good portion of the load off the transmission, which should help it last longer (not as much heat generated).

If you still insist on going with 4.88s, then I would again recommend you stay out of 5th completely while towing.

Yes I agree that 5.13's would make towing easier, but I don't plan on this thing being a dedicated tow rig, so the rest of the time the extra gearing would be an annoyance to me.

I still haven't seen any damage done to an M5OD due to towing in OD (not saying it isn't out there, but I'd like to see it). It does make me feel better that there really aren't any reports of M5OD failure due to towing (in general) so that's making me feel better for even considering doing so.


Thanks again for the thoughts and comments guys!