i skipped the thermal bypass. its not needed here in Ga and its just something else to go wrong. if it failed, i don't know which way(s) it could fail, but l assume fluid could continue to bypass the cooler and without a temp gauge i'd never know it.

i don't have a temp gauge to know what temp its at all the time, but as long as it gets warm enough to activate Overdrive, then i figure its ok. Even on the coldest mornings here (15-20), i get OD after a couple of miles of driving.

 

I see you bypassed the radiator trans cooler. Did you always have the radiator bypassed since the 4739 or did you try it with the radiator in the loop.
Do you have a temp gauge installed from the hotline? If so, What kind of temps are you seeing (and at what ambient temps)? Nvm, just saw you didn't have a temp gauge.

My trans loop looks like; Trans>Radiator>[thermalbypass]>4739>trans. I was thinking I could completely bypass the radiator, but wanted to leave it as factory as possible but with better cooling because I don't have a temp gauge installed yet. I also just got a new CSF 2969 with the trans cooler. If I can completely bypass the radiator safely with the 4739, I might buy an all-aluminum radiator without the trans cooler and put this one in my other Ram. I've also wondered how much the radiator part plays in warming the fluid when its really cold out vs. just driving down the road.

Has anyone compared the 4739 with and without the radiator in the loop? Is that how the diesel guys do it?

 

here's what I know and don't know:

i don't have a trans temp gauge, so I can't say exactly what its cooling to. I need to get one, but just haven't done it yet. what i really want is a small, almost unoticeable digital gauge rather than a big one that gets in the way on the dash or the A-pillar.

i originally routed the trans fluid through the radiator on my original, smaller cooler, assuming that it would provide some trans cooling and not be detrimental to engine cooling. that worked ok for a while, but in the last couple of years, i've noticed a climb in engine temp when its working hard. instead of sitting steady on 180, the engine temp was climbing to 210 when pulling a long hill. i'm thinking it was the radiator getting stopped up - and maybe in combination with the heat of the transmission dumping into it. so my next move was to get a much bigger transmission cooler, and bypass the radiator and maybe squeeze a little more life out of the radiator. that worked ok, and I think it might eliminate the problem of the engine temp climbing - but - its not 100 degree summertime, so I can't test it yet.

then - as luck would have it - the next thing that happened was the factory POS radiator sprung a leak at the seam. This lead to the all-aluminum CSF2969, and since I had already bypassed the radiator, I just left it that way.

since the coolest part of the radiator is about 140-160, and any heat you pull from the transmission will transfer to the engine coolant - i want to try a summertime of engine cooling only in the radiator, and trans cooling only in the trans. i'd like to see the engine temp sit on 180 again, and i think the trans will be alright on its own.

 

i don't think it does anything. when the engine is very cold, and the thermostat is closed, then the radiator is super cold. so the transmission gets no warming. only very cold.

if you did NOT have an aux trans cooler, and AFTER the engine t-stat opened up, i could believe that the radiator helps to warm the transmission fluid a little in very cold weather. not that you need it - as the transmission is capable of heating it up plenty....

but - if you DO have an aux cooler, then all your doing is cooling the trans fluid in stages. 200-ish coming out of the trans, 140-160-ish in the bottom of the radiator, and then COLD in the aux cooler. i see nothing really gained here.

if the price for the CSF is about the same with or without the integrated trans cooler, i think i'd just as soon have the integrated cooler since it gives you more options. it'd be my luck that as soon as i bought one with the cooler, my aux cooler would catch a rock or fender bender and i'd be dead in the water.

 

I didn't think about that. My A/C condenser has some pretty nice dents in the fins from a couple rocks that made it through the grill, but I'm not worried about a rock cracking the trans cooler (I know people have had similar things happen). It would have to take a pretty good sized pebble and some good speed to cause enough damage to crack the trans cooler that now sits in front.

I just figured that the CSF without the trans cooler might cool the engine a bit more because it has the extra few inches. I knew about the trans dumping heat into the coolant, but the hottest I've seen the motor since the swap was the needle at the middle of the '2' on 210 and the bottom hose wasn't very warm. I was kind of seeing if I could get it to 210 'safely' and it just wouldn't heat up any more. This was driving around at 55MPH, O/D off with a 7.5' plow on in 30-35F weather, so I guess that is OK. Under 35MPH I don't think I saw the needle budge past its normal spot where it covers the angle on the bottom of the '2' where my data logger says coolant temp is between 185-190F with a 180* stat. When I've had a ton (literally) of stuff in the bed, almost riding the bump stops, I might get a needles width past that low point, but not the middle of the '2' I saw with the plow on.

I'll have the trans temp gauge in soon enough, at least before the summer. The A-pillers on these trucks are thick enough so I'll probably go for a steering column pod. I love that location on my VW. Either that or where the broken cup holder is below the radio. With the cooling efficiency of the 4739 and the 180 thermal bypass I doubt I'll be able to get the trans past 180F.

 

Well I'm gonna resurrect this thread again, and any info on how well that cooler worked dvaughan? I'm looking at installing one, (possibly buying a camper) and want to add a cooler. I don't have the towing package so to my understanding I only have the stock transmission cooler, not the extra one inbetween the ac condenser and radiator. Thanks in advance.

Does anyone know how BTU will correlate to GVW in ratings of temperatures?