Ok I just got a true 4"dp for my truck (thanks Cowboy_Customs) and was wondering if someone could tell me how important these trans coolers are. My thought was to eliminate this cooler so that I have plenty of room for my new 4" dp. If it shouldn't or can't be eliminated can I move it to under where the air box is. If it can be moved can I just use hose barbs and rubber hose because right now it has metal lines going to it.

Any input and or suggestions will be greatly appreciated.

Thanks Ryan

 

While it does help cool the trans when the trans fluid temperature is well above the the engine's coolant temperature, that heat exchanger located under the exhaust manifold is more helpful to the trans in that it helps warm the transmission fluid when it's really cold outside.

Take for example Momma going to get groceries when it's 20* outside and the truck's stone cold. You know she's most likely gonna baby it (Dale Gribble interrupts . . . "Or Is She!" ). By the time she creeps the four or five miles into town, the engine coolant is just getting to the lower mark of the normal range. The transmission temperature is still well below the minimum operating temperature that is conducive to good operating characteristics and overall longevity without any help. The heat exchanger is there to add the heat to get the transmission temperature up.

I would think that pending your geographical location and how you drive the truck would determine whether you really need it or not. Living up in Maine or Alaska and just getting groceries? Might ought to hang on to it.
Living in Florida or Texas and fixing to start another eight-hour shift hauling the max gross combined vehicle weight? Dump that fat-boy and perhaps add a true auxillary cooler!

Moving it is no problem and I think a few here have done it.

The little radiator up front of the truck is to help dump the excess heat on those long sultry summer days.

Hope this helps.

 

So David... are you still running the exchanger?

When McMopar serviced my 518 he was pleased with the overall lack of sediment and condition of what he could see w/ the VB out. The sender was installed at that point and that's when I saw the heat... was running 220* going home on the highway and wanted to go even higher pulling my Jeep (ambient 90*).

I added a manual switch (it's the one hung in the stake pocket & marked "Heater" ) for the OEM rear cooler to see if it would help... VERY slight difference (it will be replaced with a cab mounted switch and relay shortly).

Friday heading to Chapel Hill (ambient 45*) it STILL wanted to run 180* with plenty of cool air thru the coolers & the fan on high. Same thing coming & going to the dyno...

I contend that the tranny is being "overheated" in the summer by the exchanger. Since I'm ONLY gonna be "fetching groceries" occasionally & towing, I'm fairly sure the tranny will heat up on it's own (WITHOUT the exchanger). My TH400 on a 26K# GVW air/oil cooler barely cracks 140* and only goes above 190* after 15 minutes of slow crawling or or high rpm hillclimbs.

So, I'm gonna bypass the exchanger. Do you happen to know what fittings are on the tranny side? I knew I should have looked at yours (MUCH easier than my "lowrider")...

 

I'm still running the heat exchanger and I believe the exchanger uses 1/2" NPT female bungs.

 

Go with a synthetic ATF if you insist on running without the exchanger. DexIII is going to be harder on the trans when it's not warmed up, especially in cold weather. Probably not that much of an issue in NC.

 

The heat exchanger side of the fitting is 1/2" NPT...the hose end is 1/2" JIC. At least on my 2nd Gen!

Chris

 

I was under the impression the ATF+4 *was* synthetic?

While I'm unsure what the unacceptable cold operating specs are, I'd guess it's well below freezing? Unlikely to happen for long in NC and if it should drop that low, I'll circulate in N to let it warm for 10 minutes before leaving..

 

ATF+4 is a GPIII-based "semi-syn." But would be a better choice than the factory spec'd DEXIII, in your case. I'd use DEXVI if I were going to go without the exchanger. It is a PAO full syn that is somewhat thinner, and oddly enough, backward compatible spec'd for the A518.

But I wouldn't go without the exchanger, in any case. The machine and it's lubricants are designed to run at a certain operating temperature. The numbers you are seeing don't look that high. >220 is pushing it for DEXIII, but sounds like you are using ATF+4. I see no prob there, assuming your temp gauge is correct.

Best approach here would seem to be getting a tighter torque converter and elimintae some of the heat generation at the source, rather than applying a band-aid solution.

BTW, if you are using +4, that alone is contributing to your tranny heat generation issue.

 

Dave and ACE hit it with the cold atf thing, I had a Buick Regal waaay back in the day that i had swapped a hotted up SBC/TH350 into. It had no rad hookups for the trans and I used a huge by gigantic air/air cooler on it, while it never got too hot (I don`t think) it DID act wierd in very cold temps. More importantly, Ryan, why won`t the DP fit w/the exchanger in place? Mine fits with a mile to spare....unless you r truck is "planning" on twins I`d just keep it.

 

I'd be thrilled with 220* Max numbers, but pulling 7k#... it'll just keep going up and up and up. Engine temp is normally at the 2nd mark (1/3 from C-H)

The first test with load netted 230* (and climbing... the engine temp was at the 3rd mark) then we hit the mother of all thundershowers and even with gallons of water thru the grill cooler (and I'll assume the rear cooler) it took 15 minutes in N to cool below 200* while the engine dropped to below 1st mark

Phil says occasional 230* isn't great, but should hurt it... 240* is "pull over and cool it IMMEDIATELY!"

I have yet to test the sender (drop in boiling water under the rig), but can see the correlation between the tranny temp & engine temp when it's cool enough outside that it shouldn't be running 180*...

 

That is expected within acceptable levels, and why the heat exchanger is designed the way it was.

 

Chris thanks I haven't tried to put the 4" in yet but I know when I put the 3 1/2" in it was tight. I was looking at it and thinking of maybe trimming the frame a tad or so. I haven't had a chance to look at any with a 4" DP and auto trans yet to see how they fit I was just thinking that it was going to be to tight. It's probably not going in until spring because I have to build the box "manifold" for the 5" stacks. Yes I am to cheap to go out and buy the correct piping for the stacks, plus I enjoy doing fab work.

Ryan

 

While I didn't "remove" the exchanger from the the block, I did take it out of operation, with pretty favorable results!