I started to ask this in another thread, but thought I'd get more exposure if I titled it right. I tow my FED with a '47 Ford 1/2 truck with a 392 Chrysler cast iron T/F. Currently it uses a '56 (ish) Chrysler trans cooler that originally mounted off the water pump - it's kinda goofy and I'd like to get rid of it. I was planning on having a factory (47) 1 ton V8 radiator re-cored, but the bottom tank appears very small - not sure I can or even want to add in a trans cooler there. So given that I want to make this bullet proof - what are your suggestions. I am leaning towards modifying the trans pan - as well as adding an aux. cooler - undecided on the aux cooler - I have a smallish one that has an integral fan built in - or I could put a HD one somewhere else - in front of the radiator??? Please - Share your wisdom!!!
Install a transmission fluid temperature gauge,and keep it under 200 degrees when towing. Fluid temp is the key to tranny life! You want a cooler which will do that. Talk to someone at an RV or trailer shop, they should be able to tell what you will need. Good Luck! KK
good quality trans kooler a must, i think the fan type is great when hauling a trailer with the starting and stopping. i would talk to one of the radiator builders about having one built for your rig. trailer weight etc. i no this always starts a pissing match, but im an aluminum rad fan. all your late models run aluminum , all the diesel pickups are alumnium. i have been in the shop for almost 40 years, repaired a load of copper rads, never have replaced an alumnium for a leak, i dont think there a car or truck built with copper anymore. my opinion they disapate heat quicker, my opinion. i also think separate trans cooler away from rad.
Based on advice, the consensus is to run transmission coolers in a series, from pressure outlet of transmission through radiator first and then through an auxiliary cooler before going back to transmission. Firstly, the reasons for this is that if the transmission fluid is hot, it will be cooled more quickly and efficiently by the radiator. Secondly, if it is cool it will be warmed up and yes they can run too cool. When they run cool condensation that may be in the system remains there, NOT GOOD. The transmission needs heat for self preservation but not too much. If the fluid is too hot after it leaves the radiator it will be cooled by the auxiliary cooler before going back to the transmission. Auxiliary coolers needs to be mounted where airflow isn't impeded as it needs to dissipate or radiate the heat, air flowing through and over does the job. If stuck for space a small slimline auxiliary coolers with a fan as you propose is the go. In colder areas and on short trips, the transmission may not get hot enough to reach optimum operating temperature. By being routed through radiator firstly it will be heated to a better temperature. I checked my late model in the garage and this is the way the big manufacturers now do it. They spend $M on R&D so why not take advantage of their expertise, it's free. I wouldn't recommend just running an auxiliary cooler, my opinion, but definitely use your radiator. Why, because the transmission generates the second greatest amount of heat beside the engine. Another thing, I always use coolant rather than water. It costs a little more but a lot more advantages. Water has contaminants that may lead to blockages and corrosion. Coolant also lubricates your water pump. A good radiator also helps. I personally prefer to run fluid line through the radiator first and then back through auxiliary transmission cooler. I've seen small air deflectors used to push air over and/or coolers in some instances where space is an issue. Don't have it too low so that you run the risk off loosing it due to road clearance issues. Last thing you want to do is grenade your transmission due to heat buildup and heat will kill them eventually. I've never been a fan of just a stand alone transmission cooler in isolation. If you add a deep pan, don't forget to match the pan with the correct pickup that sits down where it should near the base of the pan, a lot of additional fluid to cool. Normal transmission range is between 180F- 250F with pan temperature @ 60mph being 180F. Any more that 20mins @300F and you could need some repairs. When towing a load the temp can easily rise to 250F. Cruising at 60mph the pan temp could be 180F and then you pull a slight grade the temp will go to 200F+. Pull a long steep grade or tow and it could climb to 250F. If temperature climbs to 300F over a prolonged period serious damage could occur. Temperature fluctuation is normal however prolonged high temps will definitely shorten the life expectancy of your trans. Good fluid is pink, red is used and brown means you've waited too long. For optimum performance change the fluid, purge the system and change the filter every 15k miles (24k klms). For longevity used a quality trans cooler.
I have always run the fluid through the aux. first , seems to take some of the load off the rad. Engine temps run lower.
Either the '56 cooler or a radiator with a cooler, then through an aux cooler, either set up should be fine with an aux cooler. An aux in a poor location with a fan means youre dependant on the fan not crapping out. On mine after the fluid leaves the aux cooler I plumbed in a spin on filter adaptor so the fluid goes through a real filter & gets a little more cooling also. The fact that they switched from the earlier style cooler with the PF to a diffrent set up with the 3 speed TF probably meant the old style by itself was considered inadequate.
May be your radiator is a bit small, there's the possibilty that the fluid could be warming back up in the radiator if you have a big aux cooler....could be an interesting conversation on sizes of radiators (too big/small) & aux coolers (too big/small) & what combo does best for both.
Something simple that has not been touched on yet is a good quality synthetic trans fluid. I transport all over the country & I use dexron 6 supposed to be the latest & greatest from Gm. It is pricey though. My one truck that uses an auto trans. went 265,000 plus on the first trans & just over 200,00 on the rebuild & still going great
How you cool depends on your tranny pump .... Tranny pumps are not designed or intended to move a large volume of fluid a considerable distance - adding to the distance a pump has to move fluid will shorten the life. Start with your towing weight calculation. Then find a good auto tranny shop. Get a professional evaluation of your current set -up. You might need a different torque converter, a different tranny, an electric tranny cooler .... Consider rebuilding & balancing your driveline (u joints and carrier bearing) ..... Jim
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