PTO hydraulics on a GMC Top Kick

[Willie B]

I've bought a fire truck as a replacement for my C65 I need hydraulics for the dump body now on the C65. It won't carry tandem weight. I'd estimate body, and load together at 17000.

My engine is a Cat 3208Turbo. Try as I might I can't find room for an engine mounted pump. Shaft drive off the front of the engine isn't going to work as the radiator is in the way, and includes coolers for transmission, and engine oil.

I'm down to PTO as best choice. I find PTO with married hydraulic pumps of unknown specification. I'm needing at least 5GPM, 2500 LBS. Am I going down a wrong road?

 

[lumberjack]

A transmission mounted PTO and pump can easily make that flow at that pressure.

I'm building a small hook lift truck now with a 3.86CI pump, up to 2800psi. At WOT, it'll make ~45GPM, although I doubt it gets ran that fast in practice.

 

[Willie B]

There are published specs. for PTO units from a couple manufacturers. I think I can pull Something like 100 HP from a PTO. I need something like 5. There is stuff in the way preventing me from using a driveshaft to power a separate pump. What I'm finding are "Yard mule" units. I believe it was once possible to choose gear ratio, clutch type, and pump specifications. These days these trucks/transmissions are dinosaurs.
When I think of yard mules, I imagine the hydraulic fifth wheel. It raises, lowers, engages, and disengages. I'm concerned they may not need much flow, or pressure.

 

[lumberjack]

My PTOs have a direct mount pump, this hook lift, the crane, and the grapple truck. Would that not work for your application?

 

[lumberjack]

Here's the only picture I have of it, the shift cover and pump mount is off, but the pump comes back to the flange for the end housing of the trans, had to grind it a bit for clearance.

 

[Willie B]

Yes. I'm curious about output. The seller in California will ship to VT. They know nothing about it. Is it a 1 gal. pump at 200 PSI or a10 Gal pump at 2500 PSI. At this point it is a total mystery.

Oh, mine is on the passenger side of the tranny.

 

[lumberjack]

The pump just makes flow, although it will have a max PSI spec.


I didn't realize you had your eye on a pto setup already. There's no way to guess what you're looking at based on the information provided, or maybe I don't understand your question?

 

[Shimmy1]

Darn it, WillieB. You know better than to post duplicate threads. Couldn't figure out why my post wasn't there, then found out you had two.

 

[Willie B]

Darn it, WillieB. You know better than to post duplicate threads. Couldn't figure out why my post wasn't there, then found out you had two.

Sorry, after posting I checked, nobody had read it, nobody had responded, and I couldn't find it either.

 

[Jonas302]

There are not going to be very many pumps that cant lift a dump box on a single axle unless it looks like a tini tiny pump im willing to bet it will do the simple job your asking it to on top of that getting the right housing and gear for your tranny is the most important part pumps can be changed more affordably

What trans is it exactly?

 

[Willie B]

The pump just makes flow, although it will have a max PSI spec.


I didn't realize you had your eye on a pto setup already. There's no way to guess what you're looking at based on the information provided, or maybe I don't understand your question?

I've learned that PTOs can be fast slow and several steps in between. Separated pumps usually have some info. This married unit is described only as coming from a yard mule. I have no understanding of yard mule hydraulics, I hoped someone else did.

 

[Shimmy1]

Sorry, after posting I checked, nobody had read it, nobody had responded, and I couldn't find it either.

Yeah, I know the feeling. I'm not sure what exactly is going on around here, but a LOT of the guys that a guy could expect to respond are nowhere to be found. Some are still logging on once in a while, but not actively posting. Makes me a little sad, I've been following this site since the days of D8Bob and Deas Plant and am disappointed to see this trend. Maybe everyone is just too caught up with work and life......

 

[Willie B]

There are not going to be very many pumps that cant lift a dump box on a single axle unless it looks like a tini tiny pump im willing to bet it will do the simple job your asking it to on top of that getting the right housing and gear for your tranny is the most important part pumps can be changed more affordably

What trans is it exactly?

The nameplate says only MT643. It is 1990 fitted to an Eone fire truck. four speed automatic. As only one wire runs to it, (I guess back up light switch) I'll presume the M stands for mechanical.

 

[Jonas302]

https://www.heavytruckparts.net/det...EA-PARKER&model=SPOTTER/YARD-MULE&searchnum=2

How about one like this looks to have a 1/2 inch output line and isnt a tini tiny pump like some of the yard spotters that come up for the price if you had to change the pump you would still be way ahead of buying new the worst case would be the bed running slowly

That one fits on the passenger side cable shifted

 

[56wrench]

i believe the MT stands for medium torque as they are the medium series of Allison. the 643 is basically the same as a 653. the 5 stands for the number of speeds ( not counting lock-up ). the 653 has the additional lowspeed planetary assy bolted to the back of the main case and is easily seen at a glance. i would find a truck wrecker and get the complete pto and pump assy etc off a dumptruck. the allisons were quite popular behind gas engines in ford and gm medium duty trucks with dump bodies as well as smaller diesels( ie. cat 3208 ). i think they were also in garbage trucks. the pto off a 653 should also fit a 643 but may or may not need the gear changed.

 

[56wrench]

oh ya, they were more popular in cities than rural areas

 

[Tags]

Can't you just get in touch with a Chelsea dealer to find out what you need then search for one or just purchase a complete new one? Those Allison autos were pretty popular. At least that way you wouldn't be guessing.

 

[Willie B]

I've been quoted $2600, it may not work. They haven't seen a new Allison 643 in many years. I went ahead and ordered a PTO with pump from CA I'm in VT. A risky thing, I know. I'm getting desperate.

 

[Willie B]

The used Muncie PTO with attached Parker pump arrived today. PTO is in good condition except someone used an acetylene/oxygen torch to cut a mounting bolt. In doing so, they blew a big hole in the cast aluminum flange. I could cry!

Parker pump is big, but Parker's website can't find it. I will call Monday, I'm not aware it needs any seals or parts.

They will fit I believe.

Willie

 

[repowerguy]

Cuttin torch mechanics break one thing to “fix” another!