94 Monaco Hydraulic leak

[Ronbstewart]

94 Monaco Executive, Cummins 300 8.3C, Allison MD3060 6 Spd. On recent 2000 mile trip returning home,my wife driving alerted me when she got a "Do not shift light" and tranny down shifted to 5th gear at 12.30 am. A check of tranny revealed no leaks in or around it, but no fluid showing on the dip stick. Lots of fluid all over back of coach and dripping off rear engine compartment access door, I assumed the Tranny oil cooler or one of the hoses running to it was bad. Limped to Walmart at next exit and put in 3 gallons of fluid, couldn't really get a good reading of the quanity from the dip stick, even after 3 gallons there seemed to be very little or no fluid on the stick. Didn't take the chance of shutting engine off as pushing buttons on the shift pad had no effect (5 gear showing) Was only about 50 miles from home out return trip (Fl to Oh) drove about 45 MPH (RPM 2100-2300) until it almost refuse to pull,added more fluid and made it to facility that can repair it. When I went back the next day for a verdict mechanic said he checked tranny, lines and cooler and found no leaks (didn't check tranny quanity) but he claims to have found a leak (O ring seal) in a valve of some type mounted on the bottom of the main Hydraulic pump that powers I believe power steering and radiator cooling fan and is supplied by its own reservoir (about 3 gal or so) in engine compartment. I'm sort of wondering about this as I didn't think that valve or any other hyd components made connections that would allow them to connect with the tranny system. I was aware of a small leak at that valve, but it has only required adding a guart of fluid in over 2500 miles of travel also once he loosened the hose about 3 to 4 gallons of fluid drained out in his drain pain about the amount the reservoir holds, I'm not sure he checked its level at the on start and I'm sure he has never checked the tranny level as he told me he never assumed that was a problem once he found what he thought was the problem. Engine has not been restarted since arriving there. They have not been able to locate the needed O ring thus far. Has anyone else had this problem?

[Mike Canter]

Well the "do not shift light" was because of low fluid. The fluid out of the back of the MH was most likely tranny fluid. So I don't see how the hyraulic system oring has anything to do with the Do Not Shift warning or the lack of power. One of the bad things right now is you do not know how much oil is in the tranny. It could be too little or it could be over filled.

When was the last time the tranny was serviced with a fluid and filter change?

Have you tried reading the trouble codes in the tranny. Turn the ignition key to the run position and see if you have a RED Led on it the right upper corder by the MODE. There should be one if you have a Do Not Shift Warning. Turn on the key to the run position and on the Allison shift pad press both the up and down arrows at the same time. Now you are into the "electronic Dipstick" and will get a fault there because the tranny is not warm enough but you don't care. Now push the Up and Down arrows at the same time one more time and now you are reading fault codes. You should have one showing. Right it down then press the MODE button to check for more.

You should read the operators manual starting at page 94 in the link below
http://www.irv2.com/forums/attachmen...9&d=1297134243

[JimM68]

Mike's on it.

Also, it sounds like the bozos who have your coach now have NO IDEA!!!
If anyway possible, fire her up and RUN!

If it was mine, I'd have it towed out of there is I had to, to a factory authorized allison service center

[Ronbstewart]

I'm currently not able to crank it up as a hose is disconnected from the belt driven hyd pump waiting an O ring that's being replaced today. I've requested a different mechanic look at it, they have qualified mechanics as the company has the maintenance contract for our city buses which consist of different brands and they also work on buses for the AF base here all with auto trannys. I think I just ended up with the rookie. No red light showed on the shift pad, only no shift light on dash panel. I didn't play with the pad much after I couldn't get the pad to change any shift positions. Thanks for all the info.

[Ronbstewart]

Problem turned out to be tranny oil cooler system leak inside the radiator forcing fluid into the radiator and out the coolant over flow hose which discharged down on all the other hoses. They say radiator will have to be replaced.

[Mike Canter]

The good thing is that it is not the tranny. Now is the time to totally drain the tranny and change the filters to make sure no coolant is in the tranny.

[SafariDon]

I had my hyd cooler blow a pin hole leak and it went thru the 5+ gallons in a 20 mile trip. 2003 Monaco Dynasty with Cummins 400hp. The hyd system uses tranny fluid to run the power steering and the fan motors, but gave no lights or indication until it drained completely and I had no power steering. Cost to replace was $800+, but I removed it in 2/3 hours, took it to a weld shop and they arced it for $20. It just went thru a 3,200 mile trip and was 100%. I believe my reservoir held about 8 gallons of tranny fluid.

[Ronbstewart]

Wish I could be as lucky cost wise, but I'm sure it's going to be more. In my case fluid lost was by way of the tranny, no fluid lost from Hyd reservoir. Repair shop hasn't got the cooler system removed yet, I'm not sure if tranny cooler is located within the radiator or is a separate system on the out side of it and just shares the same cooling fluid, my deepest concern at this point is did it contaminate the tranny. I do most of my on work, but this was a bit above my pay grade. Coach made it to repair shop under it's own power, just wouldn't shift.