PTO basic's?

[MasterYota]

Anyone have any tips or tricks for safe operation of the PTO winch on an M37? All my experiences have been with electric winches. Are there any operational "no-no's" I should be aware of?

I guess I'm asking for operational instructions...?

Thanks again!

Ray

[maineSS]

Probably the biggest difference is making sure you're out of harm's way if anything suddenly breaks. A PTO or hydraulic winch won't overheat and stall like an electric, they'll just lug down a little more, and a little more until- SNAP! ZING!- and if you're in the wrong spot, you'll be Just A Memory...

Another thing to watch is accidental engagement of the winch when the cable is still hooked to the bumper or crossbar between the guides. My winch had the crossbar bent into a V, and I had to straighten the guides with a rosebud torch. I've seen another winch with the same problem, so it seems to be an easy mistake to make.

[712edf]

Well I have a Braden Lu-2 on the front of my 78 W200. Honestly things work best if you have two people. It's annoying hopping in & out of the cab to start/stop the pulling while trying to watch the line & keep things from tangling up. Maybe M37's are set-up differently. I like to keep my cable spooled up nice and even. That don't happen if I'm sitting in the cab gunning the throttle if no one else is spooling it in evenly. Also my winch will pull more weight than my brakes will hold, or at least more than my tires can.

Bucky

[Paul Cook]

"I guess I'm asking for operational instructions...?"

Are you wanting the operational instructions from TM 9-8030, paragraph 55, that tells you which levers to push to make the cable go out and in, or are you wanting some general winching guidance as contained in FM 20-22, VEHICLE RECOVERY OPERATIONS. (My latest edition is July 1970.)

There are operational instructions listed on the web sites of various winch manufacturers.

You can SEARCH this Forum (and others). This is a well discussed topic.

Getting "hands on" with another knowledgeable person is also very helpful.

Let us know how we can help.

[MasterYota]

Thanks for the feedback guys. Searching this forum is out, as I don't have access to those privledges at the moment. I had the same feelings about two person operation as well. Thanks Paul for the resource information, now I have another piece of the puzzle to research.

My biggest question is what holds a load under tension when the winch isn't engaged and pulling? In other words, does the PTO winch have an automatic load holding brake similar to an electric winch? Or is the load/tension simply held through the mechanical conection to the engine clutch, and the line will go slack if the engine clutch is disengaged?

[712edf]

My biggest question is what holds a load under tension when the winch isn't engaged and pulling? In other words, does the PTO winch have an automatic load holding brake similar to an electric winch? Or is the load/tension simply held through the mechanical conection to the engine clutch, and the line will go slack if the engine clutch is disengaged?The mechanical connection holds it, but pushing in on the clutch isn't going to let things come too unraveled. Probably due to the mechanical advantage built into the design to allow the engine to easily drive the winch and not the winch drive the engine. There's alot of frictional resistance in the drivetrain of a mechanical winch, but things are geared to the advantage of the engine, not the spool.

Bucky

[712edf]

Also (usually) forward transmission gears winch in...Reverse winchs out. At least on mine np205 driven braden.

Bucky

[MasterYota]

Also (usually) forward transmission gears winch in...Reverse winchs out. At least on mine np205 driven braden.

Bucky

Which gear in the trans do you find yourself using most often? Is it possible to "over-rev" a PTO? Ie, should the throttle remain at idle, or just above, or have you found it necessary to give it some juice to get things moving?

When all the conversions are done, mine will be a tcase driven unit as well. Does low range on the transfercase have any bearing on the operation of the PTO, or is it separately geared?

Thanks guys for all the help! Keep it comming!

[712edf]

Well you must understand on mine particular set-up the pto is run off of the t-case, which I shift into neutral to keep the vehicle stationary. My 4-speed 435 transmission gives me 4 speeds to choose from to winch in. If I'm just spooling in cable I might use 4th just to speed things up. This is with engine at fast idle. I might goose it time to time because I'm impatient. Also I have the hood up. This helps cool the engine a bit, plus if I were winching a load and had a line breakage the hood up might prevent something from going through the windshield. But that's just me.
The 435 is geared very low in 1st, so usually 2nd is the better choice for winching, just depends on the circumstances. Used to be vehicles with PTO's had a throttle lock to hold the engine at a faster than idle rpm. Again conditions dictate gear & rpm needed. MY engine is a 440. Its not stock. It is rather healthy! If I crank up the heat to much something is going to break maybe.
I do know that smaller engines with a PTO, particularly ford 8n tractors (and those like it) are meant to run at a higher rpm while in use, especially when engaging the PTO.

I'm just not familar enough with your drivetrain to give specific info on what would be best for you.

Bucky

[712edf]

To answer your last question. I don't thnk hi-lo has an effect on pto speed. Mine (NP205) is driven off of the input shaft.

Bucky

[MasterYota]

Sounds like we think and build along similar lines. My M37 will also be big block powered ('69 428CJ- warmed up a little) with a 435 as well. The only real difference is how the PTO is driven. I will be utilizing the unused front output on the stock ford tcase (drivers side output) to power the PTO. The rear output will power the stock NP200 down to my swapped in GM D60 and 14bolt.

This setup also lets me winch with the truck stationary, or driving the wheels at the same time, plus I can use the high/low range on the ford tcase to vary the line speed even more depending on the circumstances. I think I'll also hook the dash mounted throttle control up to the new setup as well. The rpm would remain more constant than my foot vibrating up and down. Good idea on the "hood up" practice - I can see the safety advantage already.

[712edf]

I imagine your PTO set-up will be stronger (durability) than mine, at least up to the actual winch itself. The front output of a t-case is built to handle more load than a PTO output on the side of a t-case (or transmission). I'm not familar with how much room is in a M37, but seems like you'll have that packed to the gills.

I'd like to rig up a MICO type brake lock on mine, but I'm still search for a manual brake master cylinder rod assembly.

[MasterYota]

The MICO lock is my book as well. I'll plumb it into the front lines and it'll accomplish two things: one, weight transfer when using the winch will move forward as the front end is pulled downward when winching someone else out. Two, the MICO will act as a park brake should I ever break the rear driveshaft. This will give me enough time to lock in the front hubs and set the tcase in 4hi to ensure the truck dosen't roll anywhere.

What rod assembly are you looking for? Is it the handle and linkage that activates the park drum on the back of the tcase?

I do imagine that the whole works will be rather tight under there, but the 428 is quite small, and the tcase outputs are on opposite sides of each other. The Ford case is also quite small, as its not an NP205, but a Dana 20.

I'll take lots of pictures once I get through the planning, and parts gathering stages...

[712edf]

What rod assembly are you looking for? Is it the handle and linkage that activates the park drum on the back of the tcase?I have a 78 W200 that has power brakes. I desire to switch to manual brakes. On my particular set-up the rod that bolts to the brake pedal is an integral part of the vacuum booster. It does not come apart from the booster. I need a rod to connect the brake pedal to the master cylinder, along with the plate that bolts to the firewall.

bucky

[MasterYota]

I have a 78 W200 that has power brakes. I desire to switch to manual brakes. On my particular set-up the rod that bolts to the brake pedal is an integral part of the vacuum booster. It does not come apart from the booster. I need a rod to connect the brake pedal to the master cylinder, along with the plate that bolts to the firewall.

bucky


I have to ask the question:

Why on earth would you want to downgrade your brake system from power to manual?

[maineSS]

With respect to winch rpm vs engine gear, I don't think gear selection influences winch rpm on the OEM setup, it's engine RPM. The speed can be set with the hand throttle. The OEM PTO had a rating of 30 HP at 1700 RPM, and the output RPM differs according to whether the PTO output is turning the same direction as the engine, or counter to it (lower RPMs).

[712edf]

I have to ask the question:

Why on earth would you want to downgrade your brake system from power to manual? I want to "feel" the truck when I'm driving it.

I'm an odd duck.

Bucky

[712edf]

With respect to winch rpm vs engine gear, I don't think gear selection influences winch rpm on the OEM setup, it's engine RPM. The speed can be set with the hand throttle. The OEM PTO had a rating of 30 HP at 1700 RPM, and the output RPM differs according to whether the PTO output is turning the same direction as the engine, or counter to it (lower RPMs).I was speaking about how my particular set-up operates. At a given engine RPM: higher transmission gear=higher transmission output shaft rpm's=higher t-case input shaft rpm's=higher pto rpm's. My PTO is off of the t-case. Some are not.

Yes higher engine rpm's=higher winch speed too.

Bucky

[MasterYota]

With respect to winch rpm vs engine gear, I don't think gear selection influences winch rpm on the OEM setup, it's engine RPM. The speed can be set with the hand throttle. The OEM PTO had a rating of 30 HP at 1700 RPM, and the output RPM differs according to whether the PTO output is turning the same direction as the engine, or counter to it (lower RPMs).

MaineSS - would you happen to know the pto rpm at 1700rpm on the engine? That would determine (for me) if the PTO adds any additional gear reduction to the winch drive system. If so, it could influence which transmission gear I select to operate the winch.

If I run my engine at 1700rpm while winching, I can set the PTO output speed from roughly 255rpm (1st gear) to 1700rpm(4th gear) with a corrosponding speed value for the other two gears. My concern would be turning the winch either too fast, and or, not enough gear reduction (via the PTO port) to make it pull accordingly.

Thanks for the Math guys, its all helping...

[maineSS]

There's a spec sheet at www.dodgepowerwagon.com/main/spec230.html that has some PTO stuff. It says that PTO rpm is 395 @ 1000 engine rpm, and the pto gear has 36 teeth. There are differing output rpms depending on whether the PTO is being driven the same direction as the engine (61/5% of engine RPM) or counter to it (47.5% of engine RPM) but this may apply to the side of the tranny the PTO is mounted on- left side is counter rotating, which would be the driverside if standard automotive practice is being used here. The output was listed as 35 Hp at 1700 rpm for rear tailshaft use. I haven't been able to find the gear ratio for the MU2 winch, but since it's a worm, the stepdown is substantial. If you know the number of teeth on the pinion gear, (say 20, for example), the ratio would be 20:1, as the worm is always 1.

[MasterYota]

So based on those numbers (with engine rpm at 1000, and pto rpm at 395) I presume that the PTO adds a reduction of about 2.53:1 to the winch drive system. This means that 2nd and 3rd gear in the trans should turn the winch at an appropriate speed without overwhelming anything. I have no idea what the HP would be at the front of a Tcase output would be. I'm going to presume its more than 30HP with a Big Block idling infront of it.

Is there anything like a fuseable link in the winch drive system (aside from ujoints or cable strength?). I'm wondering (as I'm not using a PTO box) if there are any shear pins etc... that I might need to design into the new drive system to keep it from grenading.

Thanks for the help guys, it looks like the PTO will be staying put at the moment.

[iranch]

I think the ratios maineSS quoted are for the transmission mounted PTO. Transmission PTOs for winches are Bi-directional (forward-reverse) and always turn with the same relationship to engine RPMs, The forward side just engages a PTO gear to the cluster gear on the transmission, the reverse side has an additional gear in the drive between the transmission cluster gear and the PTO to get the reversal and because of size restrictions the ratio changes.

The transfer case PTO would have different ratios. Transfer case PTOs are usually single direction and depend on the transmission for reverse. Forward speed is a function of gear selection (1,2,3,4) and the ratio of the PTO.

I hope this makes sense for you.


Dennis

[Desoto61]

Is there anything like a fuseable link in the winch drive system (aside from ujoints or cable strength?). I'm wondering (as I'm not using a PTO box) if there are any shear pins etc... that I might need to design into the new drive system to keep it from grenading.

I just started tearing mine apart and the winch input yoke has a pin holding it to the worm shaft. It didn't look like a shear pin but it would be a weak link. You could probably install a shear pin there if you were worried about it.

[maineSS]

The winch u-joint has the shear pin- it goes thru the end of the winch shaft. Do NOT use hardened bolts for shear pins- you have a good chance of binding the worm and pinion "together forever", or splitting the case. The original shear pin is made of brass, and is carried by VPW.

[MasterYota]

Thanks alot guys!

Its this type of knowlegde that makes this place great! This was exactly what I was looking for.

Its good to know about the shear pin. I'll have to look into packing a few of them (or something comparable) in the boonie box just in case.

[maineSS]

I disassembled my MU2 for rebuild and found the pinion gear has 29 teeth- so the reduction factor is 29:1. The gears had sat in "miracle lube" (half 90 wt and half water) for who knows how long, allowing the worm to pit and really chew up the pinion. Now I'm looking for a good used set.

[MasterYota]

I disassembled my MU2 for rebuild and found the pinion gear has 29 teeth- so the reduction factor is 29:1. The gears had sat in "miracle lube" (half 90 wt and half water) for who knows how long, allowing the worm to pit and really chew up the pinion. Now I'm looking for a good used set.


Wow, that seems like such a minimal amount of reduction, I was expecting a ratio alot deeper than that...

Most newer winches are geared almost 10 times deeper than that, but I suppose they have alot less power to turn them if comparing apples to apples (being a 4-6hp electric motor vs. a 30hp pto...)

[maineSS]

You have two reductions, one being the PTO, the other being the winch. At the 395 rpm/1000 rpm tranny speed, you end up with 13.6 winch drum rpms @ 1000 tranny rpm (395/29), which is a 73.5:1 reduction. What is the typical electric motor rpm- all the reduction is being done at the winch, so a 1750 starting rpm will need more ratio.

[MasterYota]

As usuall MaineSS your math is spot on with your logic. Perhaps you can shed some light on a rumour I've heard as well. It goes something like this:

I've heard unsubstantiated rumours that the Military rated all their equipment to 50% of its civilian counterpart. In other words, a 3/4 tonne mill spec truck, would actually be rated as a 1.5 tonne truck in the civilian world. I've heard this is true for the winches as well, having been told that the M37 winch was rated at 7500lbs for mill spec service, but its actually closer to a 15000lb winch in real life. I would assume that this was done so that under battle field conditions, the GI's could get away with thinking they've overloaded a vehicle, but in reality its still be capable of performing its duty just fine.

Any thoughts? I keep looking at the MU2 and think that its just too big a winch to be rated at only 7500 lbs of capacity. If thats the case, has anyone out there found themselves in a situation where the winch hasn't been able to pull the truck out?

[712edf]

Seems like on other vehicles (civilian) the MU2 was rated at 10000lbs. Don't know who gave it that rating (Dodge, Braden?).

Bucky

[Desoto61]

I've heard unsubstantiated rumours that the Military rated all their equipment to 50% of its civilian counterpart. In other words, a 3/4 tonne mill spec truck, would actually be rated as a 1.5 tonne truck in the civilian world. I've heard this is true for the winches as well, having been told that the M37 winch was rated at 7500lbs for mill spec service, but its actually closer to a 15000lb winch in real life. I would assume that this was done so that under battle field conditions, the GI's could get away with thinking they've overloaded a vehicle, but in reality its still be capable of performing its duty just fine.

For the most part I think you are right, or at least close. The design specs of most of the military equipment I deal with is conservative compared to the actual limits. I don't know that they downrate it 50%, I'd think more like 75% but that's academic. Naturally with these machines more likely to be in severe conditions than their civilian counterparts that extra margin of safety leaves extra room for operation under less-than-ideal conditions.

As for the winch I don't think it's downrated quite that much. I thought the Braden service manual specified that 12k lb and under winches used a dry brake while over 12k lb used a wet brake. I thought the primary difference of the miliary winch was better sealing against water infiltration since they could be used for fording deeper water.

[maineSS]

I've heard, but never actually verified, that the earlier Bradens had a smaller shear pin dia. than the later 10,000 lb ones. It would be interesting to compare things like the drum shaft dia, gears, etc from a 7500 lb rated winch to a 10,000 lb one and see if any differences exist. Maybe Paul from the Texas Powerwagon Museum would have some data?

[Rodney]

What are the wire rope capacities of the different Dodge/Braden winches? If one were to go with a stainless rope, what type would he use? I do not know of a stainless fiber core rope, but it might be out there.

[MasterYota]

I can't speak about the varying winch capacities, but I can speak a little about my experience with stainless wire rope. It was terrible. I had about 100' of 1/2" stainless cable on an 8000lb. winch. It was so stiff that it was a total PIA to wrap on the drum. Whenever the tension on the cable slacked at all, the cable would go all snaky on the drum and make a real mess. I'll never use it again.

I would choose a much more limber steel cable, or even the newer synthetic rope before using the stainless stuff. I will admit however that the design of the stainless cable probably played a role in its handling characteristics. I used it before I had any knowledge of cable makeup (my knowledge is still at a minimum!) such as strand count, wrap direction, ect...

[maineSS]

When I get my winch rebuilt, I'm going to evaluate some of the synthetic alternatives. Yale Cordage, whom I work for, makes synthetic rope for extreme duty application in industry, and we've made some stuff for the 4x4 Offroad market. I'm looking at a product called Uniline, which we bought a company to aquire, which we're going to be making with exotic fibers like Dyneema and Pobon. It has a tightly braided outer cover, but the center is composed of parallel non-braided strands- the strongest type of construction.

[Desoto61]

I'll be interested in your findings. I've seen some stuff on the new synthetic winch cables and wondered if it was worth the expense. Seems be a lot safer than the steel cable but less durable.

[maineSS]

The biggest problems synthetics have are (1) UV exposure, (2) sharp edges, and (3) Dirt pickup. You can coat the fibers or jacket the rope to minimize UV exposure, and jacketing definitely helps prevent dirt from infiltrating and abrading fibers. Pulling over a sharp edge is a big No-No. Yale has been developing ropes to replace steel cable in the Western logging industry, where the weight saving and handling ease are big concern in Highline operations. We also do a lot of Utility pulling rope for 765 KV line construction, Arborist climbing line, and Marine racing (America's Cup, Southern Ocean stuff).