Transmission oil cooler?

Ed Hackenbruch · October 24, 2016, 08:45:43 AM

Like Lin said, on my 5A the PO put a cooler to the outside of each radiator ......no fans needed, never ran hot, in fact the temp gauge usually never rose very much. Never saw it get above 160 degrees. Even though Clifford says the Allisons don't like cold temps, mine never gave me a single moment of trouble in the 12 years/90,000 miles that we had it, the PO never had a problem with it during the 127,000 miles that he drove it and the new owner hasn't had any problems with it either in the 15,000 miles he has put on it so far. I did switch over to transynd when i got it.

Stormcloud · October 24, 2016, 09:30:48 AM

I installed a Hayden 2305 cooler to cool the MT654 I installed in my MCI7 several years ago. Its rated at up to 108,000btu heat rejection.

This link
http://www.haydenauto.com/upload/HaydenAuto/Documents/Cat_Hayden/2007-hayden-trans-oil-coolers.pdf
shows the various coolers and Allison requirements ( page6 ).

This is the chart I used when I purchased the cooler. I also installed 2 fans on the cooler, but have never needed them.

The cooler is mounted in a single mesh door that replaces the double doors on the rear of the coach.

luvrbus · October 24, 2016, 09:33:04 AM

Quote from: Ed Hackenbruch on October 24, 2016, 08:45:43 AM
Like Lin said, on my 5A the PO put a cooler to the outside of each radiator ......no fans needed, never ran hot, in fact the temp gauge usually never rose very much. Never saw it get above 160 degrees. Even though Clifford says the Allisons don't like cold temps, mine never gave me a single moment of trouble in the 12 years/90,000 miles that we had it, the PO never had a problem with it during the 127,000 miles that he drove it and the new owner hasn't had any problems with it either in the 15,000 miles he has put on it so far. I did switch over to transynd when i got it.

If you tore one down that has been run cold you would see why Allison wants the 160* to 220* it shortens the life you go from a 1 mil mile down to 3 to 500,000 which would last the average bus guy all his life.They do just as good on 10/30 or 15/40 engine oil as it does on the Transynd IMO,the more oil you can get into the system the better off you are even with the 7 inch pan the 600 series hold about 1/2 the oil of a 740 with a 5 inch pan

bevans6 · October 24, 2016, 12:08:35 PM

So, not too hot, not too cold, but just right... Great. Now I have to channel Goldilocks...

Now I found a cooler that I am afraid is too big...

I mentioned I was looking for an oil cooler to my buddy and he said there on one on a John Deere engine in his storage yard that used to cool a compressor that I could have if I thought it would work. I went and got it. It is a double pass, double row cooler with a core of 20" by 24" by 3" There are five tubes per pass, total of 20 tubes, each tube is 3/4" OD, it has fine aluminium fins that look in decent shape. Overall size, what with the header tubes on top and bottom, is 32" by 23". It weighs about 50 lbs empty, and it would probably hold over a gallon. OK, I just worked it out, 1.25 us gallons. Add a quart for a filter, another quart for hose and fittings, almost two gallons of extra fluid.

How do you deal with all that oil not draining back into the transmission sump and over-filling it? This was mounted vertically with the in and out on the top, so gravity would keep the oil inside the cooler. If I have to mount this laying down flat (the only space I can think of to mount it is lying down flat on the floor of the passenger side of the engine bay, kind of under where the OEM air conditioner compressor frame is) then what keeps the oil inside the cooler?

Brian

Lin · October 24, 2016, 12:15:34 PM

Ed, as I once mentioned to you, I think that it is quite possible that your transmission oil temp sensor was mounted in the wrong place. When I first installed mine, it was suggested that I put the sensor in one of the small plugs on the side. When I did that, the gauge barely moved at all. However, I was soon informed by an Allison shop that those were test ports and would not give an accurate reading, so I moved the sensor to be inline in fluid output going to the cooler. Then it began to behave in a way that reasonably corresponded to the actual use conditions.

luvrbus · October 24, 2016, 12:27:13 PM

Not to hot not to cold you can control it, but that is why Allison preferred the water to oil setup, the gauge should be mounted on the torque converter out cicurit or in the sump but the sump installed gauge will read lower because it has gone through the filters and what ever type cooler you have test ports are not to install a gauge in there is no circulation

Fredward · October 25, 2016, 08:40:45 AM

Brian,
Judging by the tenor of this thread and the one about shift cable, I take it you are putting a 647 in your MC-5? I did that three years ago to my MC-5 and could share lots of experiences with you. PM me and I'll give you my phone number. I haven't been on the board much this summer so I missed out on a lot.

I added an air to oil cooler, installed vertically at an angle right where the OEM AC compressor would have been. Never had any issues with all that extra oil, but I had to have the engine running to get an accurate oil level reading. I installed a 24 volt thermostatically controlled radiator fan and set it to come on at 195 degrees. I also installed a "T" in the supply line for a thermometer but never got around to installing the sensor. I ran 15-40 in it but planned on switching to synthetic after the second oil change but sold the bus before that happened.

Before putting the engine back in I had to make some motor mount shims. About .8" . And when you have the driveshaft built it's going to be a spendy one. Basically close coupled yokes and you'll need to clock it at 45 degrees. Check out the OEM one, it is keyed to slide together only one way. And it's 45 degrees out of phase. And in an MC5A you have to cut a hole in the floor under the bed to fit the engine back in because of the shim. Maybe a 5C is different there. And finally, I decided to weld spacers in above the body stops to make certain the drive shaft didn't hit the axle when the axle travels all the way up. I think the spacers were about 1". When you see how close that axle housing gets to the drive shaft you'll see what I mean.
-Fred

bevans6 · October 25, 2016, 12:57:12 PM

Thanks Fred, I will shoot you a PM on the board here. I have read about your conversion, I have the threads book marked. I have a feeling that the shims are required to allow the driveshaft to clear the axle at full bump, correct? I am working on the driveshaft now, I have found suppliers of sleeve and shaft ends somewhat reasonably priced on line, but I am waiting for a call from the driveshaft shop that has the stock driveshaft to see what they recommend. I have a yoke output on the transmission, so different from your flange output. My driveshaft will be 17" long from center of the trans yoke to the flange on the drop box.

My current question, which I will start a new thread for, is what is the thread on the drain port on the pan? I need to adapt a dipstick to one of the drain ports.

Brian

eagle19952 · October 25, 2016, 02:21:59 PM

granted i am a Eagle with a HT740 and 8v71..... i do not have an air to oil cooler. never, have overheated with the coolant to oil cooler, what am i missing here ?

luvrbus · October 25, 2016, 02:44:47 PM

Quote from: eagle19952 on October 25, 2016, 02:21:59 PM
granted i am a Eagle with a HT740 and 8v71..... i do not have an air to oil cooler. never, have overheated with the coolant to oil cooler, what am i missing here ?

The MCI part

,I too have always ran a 740 in a Eagle with the water to oil cooler with a 8V92 and never had 1 heat up

bevans6 · October 26, 2016, 04:38:57 AM

Donald, since this is a retro-fit conversion I don't have a water to oil cooler the way an install designed for an automatic would have. I also don't have excess cooling capacity, this being an MCI with a much higher powered engine than stock. So the air-to-oil cooler will be the only cooler that the transmission has.

Brian

eagle19952 · October 26, 2016, 06:50:44 AM

Quote from: bevans6 on October 26, 2016, 04:38:57 AM
Donald, since this is a retro-fit conversion I don't have a water to oil cooler the way an install designed for an automatic would have. I also don't have excess cooling capacity, this being an MCI with a much higher powered engine than stock. So the air-to-oil cooler will be the only cooler that the transmission has.

Brian

i guess, then, that i would wish for both