XM-816 pto issue

[Bigfry78]

I wish I had found this forum two years ago. It's awesome. I have a question that I hope somebody finds simple.

I am a crane operator by trade, local 627. I bought a 1970 refurbished in 89 xm-816 crane bed, no truck. I will shortly find the appropriate place and post pics and progress. I mounted the 17000 lb bed on a C-65 I already had. I am very close to testing, but I have to get the proper pto. I read the TM for it, and it said 4th gear so 1:1 ratio at the tranny and 1200-1250 engine rpm. My question is, on the 5 ton these are normally mounted on, does the pto itself have and reduction or overdrive? I can't find that info anywhere. If I am right it is 1:1 but that will be a costly mistake if I am wrong. I can get a pto with reduction, 1:1 etc, I just need to make sure tranny is the normal 1:1 and if the pto itself is 1:1. I will add gearing if necessary for the 45000 lb winch to have a appropriate amount of torque.

Thanks very much for any help.

 

[73m819]

The out put is 1 to 1, the pto thay are talking about is the TRANSFER case pto, this is a direct output 1 to 1 for what ever comes from the trans, so 1200 rpm is the pto output rpm.

to drive the rear winch you need a heaver pto than a trans pto, the transfer case one is built for this load

 

[timntrucks]

yes it goes thru a very large diverter that splits up between the crane and the rear winch. do you have that part? there is a m816 being scrapped out in miss now. so you might can get some parts from him csm davis has that one. send us some pics too

 

[Bigfry78]

Thank you very much 73m819. That's what I needed. I will prob. drop the gear reduction via chain and sprocket for the rear winch, to get a similar gearing as 3rd which is what the tag calls for, for heavy loads 5th for light loads. If 3rd is 1.79:1 and 5th is .78:1, I might get something that will still give me the reduction or part of it, and be able to bring the rpms up on the engine to achieve the nominal speed. I rarely need full throttle at work on any of our cranes. If it doesn't hold up, it will be on the tranny shop, they said it would handle all I can throw at it, and that its used for large winch trucks. I can get a 40-105% of engine speed setup, so maybe somewhere around 70-85% will be able to do both decently, 70% would make 1700 rpm about perfect for the crane, and hopefully be gearing would be decent for the winch as well, at least comparable gearing to the original. Idk, that info though is very appreciated.

Timntrucks, yes I have the splitter, stinkin cv on it was broke, 700 bucks later its happy. Thank you. Yes will deff be posting pics very soon.

 

[73m819]

The winch load is a drag load as compared to a lift load, with the winch low gearing is needed which puts a load on the pto, most hyd lifts require just enough power to over come the load.
The tm states that 1250-/+50 rpm is max , more may damange things (I guess over rev the pump), so 1700 won't work, if fact I found that idle (600) would work find in most cases.

 

[Bigfry78]

Here's some pics.

 

[timntrucks]

truck is looking good bigfry that bed is going to be super nice on the rig. you will be happy with it im sure. i too only use my wrecker on just idle almost all the time. lets hope you find the parts to get it going your way. keep the pics coming too

 

[Bigfry78]

Tim, 1700 engine rpm, with a gearing reduction in the pto that would bring the rpm coming out of the pto to 11-1200 rpm. That way I have to rev it jus a little to get the same output rpm as stock on the 5ton. It will also allow me to have a little lower gearing to be closer to the 3rd gear stock that it recommends for heavy pulls. I deff will keep the rpm at the pump to 1200 rpm or less.

 

[Bigfry78]

Thanks too Tim, I sure hope it all works when I'm done lol.

 

[crasheej]

I use 5th gear at an idle. Has done the job for all the jobs that i've ever done. Plus saves fuel. I see the power dievider is on the bed you'll need some way to ingage, disengage it. That is where you get the control to the crane or the rear winch. Let us know how thins work out. Good luck.

 

[NDT]

Looks good on the Chevy. Too bad boss man wouldn't let you take the Demag I mean Grove home for the night one night to set that bed.

 

[Bigfry78]

Thanks Crash. It has all the levers, most still attached, there is one that's attached to the splitter that needs to be connected to a additional lever, maybe it was originally in the cab. Then the throttle I will build a cable setup to the original lever. Etc. I found one pto with a 84% engine speed. Which will be similar to 3rd gear. Probably going to purchase that one. That way enough grunt to pull, and with a lil throttle I will still be able to hit the 1200 rpm at the pump if needed, all without over revving my 366. Should be about as perfect as I can get with this setup. Might go purchase it tomorrow. Lol, another 700 bucks.

 

[73m819]

one question, will the frame handle the trekking and stress of the crane and the pull, the mil and most civi frames are double or triple plus extra cross members, also what about the springs

 

[Bigfry78]

NDT, I used our boom truck to haul it home and unload it lol. I had a job with it in my hometown the next day, and was on it when I bought it. Was meant to be. I think it looked alot better after I mounted it. I really like how it sets.

 

[Bigfry78]

Lol, got griped at to remove names.

 

[Bigfry78]

73, the truck has a heavy haul package on it. It was a propane hauler. It has a double frame, and the springs are about 2 inches from even touching the overloads. Tires look good, etc. I believe it will be fine. Pretty sure it would be fine with 3-4 thousand more. The rubber chart is basically null, should be able to do a little, but mainly it will need the outriggers. I'd say I could pull tow truck duty with maybe a 1 ton, but no way do I think I could add more than that on the hook. Prob won't ever anyways. Maybe carry pipe or something small around the house. It's no 5 ton, but I believe it has potential within limits. I will also build some spades for it too.

 

[crasheej]

Was a tight fit after you got it loaded wasn't it, Got her done though didn't you. My kind of guy. Do what you got to to get the job done.

 

[doghead]

That looks really nice on that truck! It should be a very useful setup.

 

[Bigfry78]

Yes, it was a very tight fit Crash, to dodge all the crossmembers. Prob haveta notch one crossmember for the pto shaft. I bolted it down with 20 1 inch grade 5 threaded rod. I still gotta fab up a brace for the 5 bolts on each side that supports the drag winch. The truck when I got it, was freaky. My x father-in-law gave it to me. I was not equipped for this ten yrs ago. It was a cab and chassis. I have a homemade 3 axle trailer a friend pulled for me with a bumper hitch on a one ton chevy van. Lol, insanely dangerous but I got it home. It's a 78, so am I. It also had a flyer in the door for Fry's propane. It has my name too. Freaky. Next thing ya know it's gonna be running ppl over and fixing itself(Christine) lol.

 

[Bigfry78]

Thank you Doghead, it will be very useful to me. Ima almost 23 yr powerlifter and seems to always be lifting large items. Funny that Ima crane operator too, I pick things up, and put them down. Usefulness, oh heck yes. I built a raised concrete porch off my house. 3 in square tubing frame, handrails, etc anchored by 10 pillars. 4 floor panels I poured, .5 inch rebar on 6 in centers. 2500 lbs each. It was all my tractor wanted to lift them using my bucket as a spreader. I built eyes into the concrete. I helped the tractor get over the edge, my boys would hold the lever back, while I deadlifted the rest to get it up. Last one, I put my 7ft brushhog on, choker around the rear tire frame, over the rops, to a 4ton come-a-long overhead, to a d-ring on the bucket. Whalla! Homemade superlift attachment lol. Worked perfect. I have pics n vid of all this. Lol.