Transmission Pump Leak

[Discover 17]

I was hoping that someone could help me out identifying what this is (top of the picture) on the side of the transmission and what it function. It has some larger lines coming from it and one smaller one to the bottom of transmission pan. It has been drip oil on the floor and appears to be transmission fluid. Was hoping to know what I am talking about before I call the shop for repairs. 

I have had the motorhome stored for several months now. I have cleaned it off with some de-greaser to better identity it and hope to see where the leak maybe coming from. I noticed this small leak earlier, however I believe it has gotten a little worse now. Plan on leaving on a trip soon.

This is on my Monaco Signature Commander IV. 600 hp Cummins ISX and Allison Transmission. 

Thanks in advance for any help.

 

[Ivan K]

Hydraulic pump driven by transmission PTO.

[Discover 17]

Ivan,

Do you have any idea what the pump function for. What does it support. 

[vito.a]

It operates your engine cooling fans.

On ours the small braided steel lube hose developed a leak and I changed it. 

[Discover 17]

Thanks Vito

[waterskier_1]

It also operates your power steering. 

  -Rick N 

[Ivan K]

6 hours ago, Discover 17 said:

Ivan,

Do you have any idea what the pump function for. What does it support. 

Sorry, got busy doing nothing in the morning but you got your answers above...

[Discover 17]

Sorry for the long explanation. To get to the point, has someone out there have some knowledge on this. Below I have laid out my research this far. I hope this makes sense. 

Following up on my continued research on the PTO / Pump leak/drip. I have taken it in for service. Tech repairing the issue has told me it is the PTO seal on the shaft to the pump is the problem. PTO is a Chelsea model #X126705. They tell me the unit is no longer available. We are trying to find the replacement or a rebuild kit to repair it.

I have contacted REV with no luck, also several part warehouses in my area, again without success. This maybe be a number for Monaco only.

I have also talked to several (two) RV tech in the Monaco arena, and they both said the same thing. The internal pressures inside the PTO is minimal. Repairs could be to double gasket the PTO to Pump and a little gasket sealer. The current tech working on it would not advise this, as not to cause damage to the transmission.

Any help out there would be greatly appreciated. 

[waterskier_1]

I had a similar problem, which I found is not all that uncommon.  Mine was the front seal of the Hydraulic Pump itself allowing transmission fluid to enter the Hydraulic System, causing the hydraulic reservoir to overflow.  My mechanic said there was no way the pressure in the transmission could overcome the seal in a hydraulic pump that typically operates at 5 - 10 times the pressure.  I had procured a new pump, after reading that the success rate of resealing it was not good.  He reluctantly installed it for me, and it solved my problem.  But from your description, it sounds like you have a leak at the PTO shaft that is leaking - on the ground?  If so, you may have a different problem. 

  -Rick N.

Currently in Tucson, AZ 

[Discover 17]

Thanks waterskier_1

Mine is on the PTO side. I am currently awaiting a responds from Parker Chelsea Products Division. They are checking with the engineer to see if there is a cross reference to the current pumps. I will post any information I receive.

Thanks again

[vito.a]

I'm sorry, but I think you need to be much more involved in this or you are going to be led in circles.  

I don't understand how the tech can narrow it down to the PTO seal.  He would have to disassemble the hydraulic pump from the PTO to even see the PTO seal.  And that's a big job because those huge hydraulic lines need to be removed and there is almost 20 gallons of hydraulic fluid in this system.   I had a weight lifter friend help loosen the 2" B-Nut on the hydraulic hose and it took 20 min of straining.    

This is the link to the post I made on repairing ours:  https://www.irv2.com/forums/f115/sauer-danfoss-hydraulic-pump-rebuild-455664.html#post4895665

The Cummins PTO to hydraulic pump gasket is Cummins part number 3916042.  They are available on eBay.  I'd get two of them and a tube of Permatex Ultra-Grey gasket sealer.  

I also replaced one of the dash 4 steel braided hoses from the transmission to PTO and replaced the shaft seal in the hydraulic pump.  

I hope you get it straightened out.  

 

Edited April 18, 2023 by vito.a

[trailmug]

Were you able to resolve? Old thread, pardon. Lots of good info in this thread. 

https://www.irv2.com/forums/f115/sauer-danfoss-cpc-1047-hydraulic-pump-444138-5.html

On our coach, (Monaco?) used the four-bolt gasket between the hydraulic pump and the PTO, on a two-bolt pump/PTO. It had been leaking for years and I finally got around to pulling it off. The pump can be removed from the PTO easily, and the gasket between them replaced without removing the hoses. Only a little trans fluid will leak out of the housing when you slide it off. As far as I know, only this gasket can result in leaking trans fluid to the ground at this location. The hydraulic system has its own fluid, though on my coach they were both red. A blot of each on a paper towel should tell you which it is. No leaks in 4 years after changing to the correct gasket. Cummins part 3916042. If it's held on with 4 bolts, there's a different part number.

Edit: On rereading, Vito had that part number above 😁  but my money is also on the pump-to-PTO (silver to red) interface. 

Edited Friday at 11:01 AM by trailmug

[Bill R]

@trailmug

Rob - I think this is a common issue as I have had the same small leak for the past several years.   I bought the new gasket, and removed the two mounting bolts, but then realized I would have to disconnect the hoses to get the unit out far enough to get the gasket over the shaft.  
 
What engine do you have?  Mine is the 400ISL.  Seeing your comment above about not needing to remove the hoses has me wondering how to do that.  Can you elaborate more?  Or perhaps if we have different engines the orientation is different.  

Thanks. 

[trailmug]

Bummer, maybe there is a difference in line length or orientation, this is on the ISX600/MH4000. I don't even remember considering the hoses, I was just able to slide the thing off (toward the front of the vehicle) and set it aside. If memory serves, the shaft protrudes from the pump into the PTO. I had to wiggle the shaft a little bit to get it to slide back in, but it wasn't difficult enough to be memorable. 😐

Edited Saturday at 01:34 AM by trailmug

[georgecederholm]

I had a similar leak from the PTO, and had WWWilliams (Allison distributor in Phoenix) look at it. They determined it to be a bad internal seal, replaced it, and sent me on my way. All looked OK until I got to the first Rest Area in CA on I-10. Leaking again. Crawled under and found that the tech had stuffed 3 shop towels around it so it would look OK until I was well down the road. Never did find out if they actually replaced a seal. Anyway, I found a place called “PTO Sales” in Fontana and they were able to diagnose the real issue: my PTO had a hairline crack, possibly from being dropped at some point. They had a replacement overnighted from Louisiana and fixed it. 

They now appear to be part of “TruckPro”, but still handle Chelsea PTOs.

https://www.truckpro.com/search/chelsea/
 

It wasn’t until several years later that I ended up with the same issue Rick mentioned above, where the hydraulic pump was allowing transmission fluid to overfill the hydraulic reservoir. That didn’t involve an external leak at the transmission, PTO, or pump. Just at the reservoir overflow in the rear.