Overheating 1999 Diesel Cutter

[Clyde Gartman]

I have a 1999 Cutter diesel with a 6 speed Allison transmission. The temp is getting to the high side of normal with trans temps reaching 220+ I understand the trans and engine are both cooled by the same system but where should I start looking for the problem (or is it a problem) ?

I called the CAT people and they said "Nothing to worry about until it get out of the normal range" I usually pull into a rest stop and it cools very quickly (within 10 minutes it back to normal)
I bought the Cutter used and it has 40,000 miles on it. I've checked the levels of the transmisson and coolant.

I might add that I was pulling a light wieght auto and was going up some hills and the outside temp was about 90, but it has done it befor when I was not pulling an auto and the outside temp was about 100 degrees.

I am not a mech but would like to change the transmission oil at least. How hard is that to do?

Thanks,
Clyde

[74Argosy24MH]

Go to Allison's site and type 1099b in the search box. That is a pdf with recommended change intervals and fluids for the different transmissions.

John

[John Brimer]

I have the definitive solution to your problem, because I have had the same running battle on my 1999 Cutter.

First of all, there was a recall to replace the valve cover breather tube on the engine. This recall MUST be done to prevent a further occurance of your problem. The original breather tube ended at the bottom of the engine. This arrangement allows the engine blowby (which is more than you can imagine as normal) to be collected by the fan, shroud, innercooler, and radiator. The exit of this tube MUST be behind the radiator. Unfortunately, this creates a problem for the towed vehicle unless some sort of catch can is manufactured. (I am working on that)

Next, the radiator and innercooler MUST be removed and completely cleaned. You will not believe the amount of imbedded cruded that accumulates between the innercooler and radiator. Also completely clean the shroud and fan. I recommend that you do not replace the belts at this time. I did that, and in less than a thousand miles, I had to replace the new Green Gates water pump belt with my old belt. (which I kept for emergencies)

If you play your cards right, the whole thing should be covered under the recall, unfortunately, mine was funded and designed by me!

I know this sounds crazy, but I pull a 20,000 lb race car trailer behing my 35 ft Cutter. I have to slow down to 60 and put in in 5th gear on hilly terrain and in 95+ temps to keep operating temps in normal range. I did install a custom made cooler for the transmission with auxiliary fan. This helped before I solved the problem. Now, I hardly have to use the transmission fan.

I put 20,000 to 25,000 miles a year on my coach. I encountered the heating problem in my first six months of use. It took me a year to figure out the problem. I tried cleaning the radiator without taking it out, it does NOT WORK.

I would be glad to help you anyway that I can.

John

[HowieE]

If you have not yet seen what can become accumulated between your radiator intercooler and AC condenser take a look at my web page noted in my signature. These pics represent 9,500 miles of use.
If in fact your breather tube is forward of the radiator and discharges any level of oil vapor I would assume the accumulation of bugs would be increased due to the oil file that may be present.