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Discussion Starter #1
I have made up my mind that I am going to install a cooler for my G56 Transmission. It runs hotter than I am comfortable with and I think it would be a worthwhile project for trans life as well as peace of mind.

There are lots of options but I will for sure need an oil pump and I will filter it. I have a filter head sitting on the shelf and I believe it is 1x16 threads but I will have to verify. I plan on using a standard lube filter.

Is there any reason I can't run a stock automatic trans cooler that mounts to the radiator? It has a built in thermostat and I could just run the pump relay on a key on power source with constant filtration and cooling when needed. I searched the forum and it looks like the built in thermostat closes at 140 degrees. Does that sound right? If so that would be about perfect. If I ran a remote cooler I would likely need a fan and a thermostatic switch to turn it on and off.

I have access to a 99 V10 auto that has a bad motor. I might go take measurements on this cooler to see if there's a chance of making it fit.

I already have aluminum PTO covers that I have drilled and tapped years ago with something like this in mind.

Any thoughts or input on this are appreciated. I will keep this updated as I go. I plan on ordering parts in the next week.
 

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Discussion Starter #4

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I put one on my 2003 manual. the Fill port is an npt and you get a pto cover and tap into that for your suction. Mine gets hot only when in overdrive and either pulling something or going 70+ unloaded. I ended up mounting a 32 row heat ex-changer with fan over the driveshaft with mine and I have a temp gauge in the truck. I just manually turn it on when I need to. It definitely helps keep temperatures in check. I also like that i put a filter element in it so I can filter the oil every so often.

I also use the pump to fill my system.
 

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Discussion Starter #7
When I'm towing I have to keep it in 5th for any chance of staying under 230 degrees. If ambient is hot it may run 240-250 in 5th. If I run in 6th even on flats it climbs above 230 easily.
 

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When I'm towing I have to keep it in 5th for any chance of staying under 230 degrees. If ambient is hot it may run 240-250 in 5th. If I run in 6th even on flats it climbs above 230 easily.
Coming home last week it was 101 outside temp. Pulled some steep grades in Idaho with my Logan living quarters 3 horse trailer. With 2 horses I stayed in 5th and saw 240 245 on the steepest grades otherwise 210 to 220 and I have the Trans Cool covers from Geno's
Roughly 350 miles one way home so she was heat soaked.
6th is not even an option when it is that hot outside
Running Mobile Delvac 50w

So I would like an additional cooler as well.

Which side do you have your temp sensor in? Mine is in drive shaft side Not exhaust side.
 

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Discussion Starter #9
Mine is in the driveshaft side as well. There was someone on here in another thread that suggested most of the heat is coming from the exhaust. I added more exhaust wrap and rigged up a shield on the pipe. Haven't towed but I don't think there's a significant improvement. I drove it empty to work a couple times. It's about a 45 minute drive and most of it is cruise set at 72 or 73 in 6th. I will get up to 195 just in that short time with ambient temps in the mid 90's.

Several years ago I hauled a 40ft high cube shipping container home from salt lake. This was before I had the temp probe stuck in the transmission, it was actually in the rear diff at the time. It's pretty much a long slow climb from salt lake all the way to Evanston on the interstate. Ambient temperature was over 100. Hottest the rear end got was 210. This was when I decided that I would never have to worry about the rear end temp and moved the probe to the transmission. I was driving based on coolant temp. I would back off when the coolant hit 230, I was able to stay above 65 at most times. I had no idea that the trans ran hot and I wouldn't be surprised if I was over 260 for a lot of that trip.
 

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Discussion Starter #10 (Edited)
Has anyone used a compression type fitting on a stock auto cooler? I figure since it is tubing it would probably work with the right size fitting. Or am I going to have to adapt one of those quick connect fittings?

EDIT: Found this. I'm not sure if half inch is the correct size for the cooler, I will have to measure. I could also just go to the hardware store and find the appropriate fittings.
Compression fitting adapter
 

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Food for thought, if you cool the fluid too much it will rob HP/TQ (big cooler up front)... it might be better to use a remote cooler with a 180* fan switch on it
 

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No problem using tube compression fittings on the stock auto cooler - that is what I am doing.
 

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Food for thought, if you cool the fluid too much it will rob HP/TQ (big cooler up front)... it might be better to use a remote cooler with a 180* fan switch on it
I use the stock auto cooler up front with no issues. I have the oil pump on a temp switch so it only turns on and cycles oil when the fluid hits 190*.
 

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I use the stock auto cooler up front with no issues. I have the oil pump on a temp switch so it only turns on and cycles oil when the fluid hits 190*.
I didnt say it couldnt be done... just saying colder fluid robs hp/tq. Its not going to be noticeable for sure as it will be a small loss.

Your solution sounds like the way to go with the temp switch on the pump.
 

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I swapped my NV4500 transmission out for a much more stout Eaton FSO-8406A. The manual on that says that the transmission should be approx 120 degrees above ambient. It instructs you to pull over and let it cool if it reaches 250 degrees. So far, I have never hit that. I have gotten up to 190 towing an rv in 5th gear.

The one thing I do like about having a tranny cooler, is I added a filter as well after the pump, It will clean the oil the more you cycle the oil thru it.
 

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Discussion Starter #16
Food for thought, if you cool the fluid too much it will rob HP/TQ (big cooler up front)... it might be better to use a remote cooler with a 180* fan switch on it
Thats why I was thinking the stock auto cooler with the built in thermostat. From what I read the thermostat sends the fluid into recycle at 140 degrees so I'm sure the trans will never actually be that cool. I guess we will see how much cooling I get out of it. Honestly I would be fine with 140 degree running temps. I can always add a temp switch to the pump if I need to.
 

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Discussion Starter #17
I ordered the pump and the cooler.
I need to verify threads on my filter head and decide on a filter.
I have some stainless braided hose leftover from another project, I will see how much and order more if I need to.
I also need to go dig through my big box of fittings to see what goodies I have and what I need to order.
 

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I ordered the pump and the cooler.
I need to verify threads on my filter head and decide on a filter.
I have some stainless braided hose leftover from another project, I will see how much and order more if I need to.
I also need to go dig through my big box of fittings to see what goodies I have and what I need to order.
Any plans for a DIY writeup? (pics too? I can host those pics if needed... Smugmug.com is what I use)
 

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Just throwing this out there, have you considered a check valve to keep the fluid from draining out of the cooler and lines and overfilling the trans when not in use? Maybe even consider a normalish oil filter head and use a standard automotive filter with an internal check valve?

The NV5600 my truck had rarely got over 200, and I was running fast coolers.

Sent from my SM-G950U using Tapatalk
 
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