Cummins Diesel Forum banner

Dump Hydraulics Tied to Transmission

3K views 16 replies 8 participants last post by  Doka971 
#1 ·
Greetings! Im new to the forum and this is my first post. I'm picking up my first diesel early next week, it's a '92 4wd extended cab with a dually conversion and a little over 73,000 miles on the odometer. Most importantly to me, it has a dump bed so I can make runs of chips, mulch, and firewood. The bed has removable sides, as well, so it can run as a flatbed too. I'll be the second owner.
When they installed the dump bed they didn't install a pto, but hooked up to the transmission for running the dump. Not ideal because of the extra wear and tear on the tranny. I'd rather not overhaul it at this time so would like to maximize what is already installed. My first order of business (on a list of many!) is to confirm that the transmission cooler fan mounted behind the drivers door is working properly, and possibly setting it up to run on a manual control as has been mentioned elsewhere in the Forum. However, even though the transmission fluid is right where it should be and looks and smells good, I'd still like to replace it asap. Considering the dump bed set-up, what kind of fluid do you think I should use? I dont know if standard fluid would be the right call for this or not? Is there anything else I could do (other than replacing with pto system) to minimize the stress on the transmission with this set-up?
I've tried looking through the threads for information on this topic but cant find anything.
FYI- I'm a complete diesel noob. I know just enough about gas engines to be dangerous, but as far as recommendations and advise I need simple, crayons and construction paper level explanations, please. For now anyway...cant wait to dive into the truck and get more knowledgeable.
Any help or advice you could offer is sincerely appreciated!
 
See less See more
#2 ·
I've owned a few dump trucks and they have been PTO off the trans or electric over hyd. I don't see how it could be run off the trans with out a PTO, you'll have to send us a picture of the setup when you get it.

I would suggest that if your worried about wear and tear on the trans to switch it over to a electric over hyd.

If it has a trans cooler then the oil's not going to overheat.
 
  • Like
Reactions: Doka971
#3 ·
I can't think how a PTO would work off an automatic tranny? But if they have truly plumbed the tranny cooler lines into the dump box hyd cylinder I would be interested to see how that works.
 
#4 ·
You would need a minimum of at least 1,500 psi to raise a loaded box.
 
#5 ·
Thanks for your responses. I'll post a pic with some additional explanation early next week when I pick up the truck.
 
#6 ·
Don't know of any 1st or 2nd gen autos that had provisions for a pto, manual trans and some transfer cases had this provision.
The trans cooler fan behind the drivers door has me thinking it has a auto trans
No way one can get enough line pressure from a auto trans to raise a loaded dump bed.

Are you saying there's no pto or no pto shaft coming from the trans to a pump, many of todays apps have the hyd pump direct mounted to the pto that bolts to the trans or transfer case and don't use a pto shaft.
 
#7 ·
From what I recall the dump pump is plumbed directly to the automatic transmission.
Im mostly concerned about longevity. Fortunately its seen relatively light use in the past and was only used for firewood.
Will definitely be following up with photos soon. Thanks!
 
#8 ·
That truck should have a A518 auto trans that doesn't have a provision to attach a pto, would be interesting to see pics of how it's setup.
 
#10 ·
This could sound dumb, well, it does sound dumb, but I'm just trying to figure out how this could work. Is it possible that it has an electric/hydro pump that uses the trans fluid and cooler as hydro fluid for he dump system?

Scratching my head on this one.
 
#11 ·
Operating the pump off of the transfer case is doable, not the best setup but it will work.
Using oil from the trans to operate the dump would cause very low oil levels in the trans when the bed is raised, hydraulics for a dump bed don't run long enough at any one time to need a cooler.

Think I'll wait till I see some pics of how it's setup so I can go, Doh. :doh: or say What the h---.
 
  • Like
Reactions: thrashingcows
#12 ·
I've read the dodge auto circulates fluid in neutral, but not in park. If you tapped in at the right spot, is there enough flow/pressure to run a dump with the revs up?

Most modern hydraulic accessories are either based on a self-contained 12v electric pack, or a clutched belt-driven pump (2wd auto tow-trucks come to mind...). There used to be a Milemarker hydraulic winch kit that piggybacked on the power steering.
 
#13 ·
Picking up on Monday or Tuesday, and looking forward to getting pics out soon. Thanks for the consideration!
 
#15 ·
Just picked up last night. I expect to have pics posted by the end of the weekend or early next week. I owe my wife a day or two of labor on the RV towards smoothing things over on the truck purchase ;)
I noticed last night when fueling that the dump bed goes up when the truck is not running. This leads me to think that it's an electric system, but I dont see any auxiliary battery or extra wiring coming off of the existing one. Stay tuned!
 
#16 ·
It has to be electric if it goes up without the truck running. Should hear a electric motor running when it's going up.
 
#17 ·
Hi all wanted to update this. It's an electric over hydraulic setup. We misidentified at first. Sorry didn't mention this previously-out of respect for everyone's time and consideration it took for you to respond initially.
The truck has its warts but is working out great. Many thanks to everyone for a great site filled with knowledgable and caring members.
Regards.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top