Allison Transmision Cooler

jmblake · October 30, 2010, 07:45:14 PM

Iam getting ready to do a transmission swap in my 81 MCI9 with a 8v71, I have the standard 4 speed manual and Iam putting in a Allison 740 auto. I got the trany and most every thing else I think I will need but what is stumping me is the cooler for the trany fluid. A friend of mine says his is cooled by a cooler at the bottom left of his engine looking in from the back but his is a 6v92, will that set up work on my 8v71? and if so what parts would I need or where to get them, I have a truck salvage yard not to far from me if I new what I was looking for. I attached a few pictures of mine to see if any one can help me out with what I may need. Thanks in advance for any help Jason.

luvrbus · October 30, 2010, 08:20:16 PM

Jason, Jim had one on a 6v92 that will work 888-349-0704 the RV Safety guy here,if he doesn't still have it Don Fairchild 661-391-4250 or Ironman (Pedco) 562-944-4192 those are pretty pricey the gasket set is 75 bucks and a all day job to install plus around 400 bucks for the 2 monster hoses .
Be sure to get the bolts and shims with it you can break that heavy joker without the shims behind it trust me on that one lol

good luck

TomC · October 30, 2010, 08:27:27 PM

Mine for the V730 is a remote mounted shell cooler connected to the engine cooling system. You could also use a Hayden oil to air cooler in front of your radiator, but that runs the risk of actually running too cool in winter. On mine, I also added an auxiliary oil to air with thermostatically operated 12v fan that is in line between the hot output from the transmission and shell cooler. This takes a lot of heat strain off the engine.
On your pictures, it doesn't look like you have enough room to add another cooler behind your engine oil cooler. The remote mounted shell cooler will probably be the best bet. Good Luck, TomC

luvrbus · October 30, 2010, 08:59:01 PM

Jason,you have plenty of room for the double cooler the filter just changes location and cooler in the pictures is removed

good luck

Boomer · October 30, 2010, 09:13:43 PM

You can get a double cooler and all associated parts from Caylor Supply in Rantoul, Kansas. Good folks to deal with.

jmblake · October 31, 2010, 06:51:18 AM

Thanks for the replies, I will check them all out, I was thinking about a oil to air cooler in front of one of my radiators but didn't know if that would be enough? I was going to put new radiators in anyways, does anyone make a oil cooler built into the radiator so I don't have to do the one on the engine? Thanks again Jason

TomC · October 31, 2010, 08:43:02 AM

It seems that the oil coolers built into the radiators are not as stout as a remote mounted shell cooler. Freightliner (and others) have gone to trans coolers in the bottom of the radiator for simplicity. I had one customer that the cooler blew and mixed coolant and trans fluid facilitating a full Allison trans overhaul (3000 series) with only 15,000 miles on the truck-but it was covered under new truck warranty (of which we of course do not have).
The double engine/trans cooler that mounts to the engine does eliminate some coolant lines, but is a big pain to install, and parts are expensive. Try to find a trashed bus and take the shell cooler-have it pressure tested-then you can install it anywhere. Good Luck, TomC

jmblake · October 31, 2010, 08:58:54 AM

TomC
What size of a shell cooler should I look for? where do you connect the water line from? the one that goes to the bottom of the radiator? Do you think a air to oil cooler mounted in front of the radiator would work or run it to cold? How about one mounted on the side access door with a thermostat controlled fan? Sorry for all the questions. Thanks Jason

TomC · October 31, 2010, 09:12:27 AM

Jason-whatever cooler you use, you should have a trans temp gauge also connected to it to verify how well the cooler is working (I believe the pickup for the trans temp gauge is on the top of the trans-but others would have to verify that). If you look for a shell cooler from a bus using a V730 or HT740, that would be big enough. The water lines are connected to a spare casting plug near the water pump for pressure, and returns to the right rear of the engine block at the 4 bolt square plate (have to drill and modify the plate to accept the hose fitting-typically a 1 inch pipe). Air to oil cooler in front of the radiator might run too cold in under 50 degree weather. A Hayden transcooler with 1 inch fittings and the thermostatically controlled fan would be a good choice-but it isn't anywhere as large as the transcooler on my truck that they installed in front of my radiator (34"tall x 18" wide). On my truck I can put a winter front on if it is running too cold-be pretty hard to do that on those two high radiators of yours. Good Luck, TomC

Melbo · October 31, 2010, 09:41:15 AM

I have a shell cooler that I took out of my bus and put in a larger one

If you want it I will take a picture of it

You can have it and the hoses

3/4 oil inlets and 1 inch or 1 1/4 water inlets

It is heavy but cheap enough at FREE

Melbo

Melbo · October 31, 2010, 10:01:43 AM

Here is a picture of my trans cooler that I took out

Melbo

jmblake · October 31, 2010, 01:53:19 PM

Melbo
What transmission did you have it on? Did it cool enough or why did you need a bigger one? If you think it is big enough for my 740 I would gladly get it from you. I was thinking my lines on my trany were 1" but Iam not shore, could reduce them down to 3/4" if that wouldn't restrict them to much. Do you know roughly how long your cooler is? I better make shore I have enough room. Thanks for the offer Melbo. Jason

Melbo · October 31, 2010, 03:25:24 PM

I will have to go and measure it -- it worked fine for my trans (I have an hp 590 ZF) but I am wanting to use the retarder and it will build up some heat I am told so I bought a cooler that is about 3.5 feet long and has 2 inch water inputs and 1.5 inch oil inputs -- my trans has 1.25 oil outlets -- the restriction to the .75 did not seem to matter when I didn't have a retarder hooked up.

I won't get a chance to measure it til tomorrow sometime.

I left it out in the weather so it will need to be flushed and dried out -- last time I had to dry it out I put it in the oven at 350 (yes it fit in the oven) for about 3hours (my girlfriend was picking up the transmission in CA so she could not object to me using the oven for bus stuff) after I took it to the car wash and flushed it out really well.

I will post tomorrow how long it is -- maybe clifford or tom can chime in to let you know if it will be sufficient to cool your trans.

Melbo

jmblake · October 31, 2010, 05:48:28 PM

TomC
Will cutting down the oil line to 3/4 hurt anything, either restricting the flow to hurt the pump or not cool enough? and you mentioned taping into a plug on the water pump, I looked and saw one on the back side about a 1" plug right above where the Y at the bottom of the pump where the water come's from the radiators, and also a smaller one 1/2" on the front side near the top of the pump, can you get pressure from any of the plugs? I also saw the plate with the 4 bolts you were talking about. Thanks Jason

Barn Owl · October 31, 2010, 09:39:32 PM

My bus has the shell cooler on it but after running through many long steep grades and high altitudes, I have decided to install an air cooler ahead of the shell cooler. I consulted with the engineers at Hayden, and at their recommendation I purchased a Hayden 1290 that I will mount in front of the radiator. I found it on Ebay for $100+shipping. It took about six months for one to pop up at that "best offer" price. The V730 on the GMs require up to 20 gpm flow, the 1290 has 3/4" fittings and will handle that.

This might help:

Locate the pdf under the Hayden catalog for Transmission and engine oil coolers.