Hey all. I just replaced my stock Trans cooler (in front of Rad) with a Tru-Cool H7B. Did this because stock cooler was leaking bad.

Anywho, the new cooler is rated at 29k GVW. Thought this would be great since I pull an 11k 5th wheel.....

First drive with it was 25 miles, not towing, on highway at 70 MPH. Outside temp was 80f. Trans temp hit 180f. Seems a little high to me but wanted to
ask around before I get pissed.

New cooler is mounted same place as stock. 1/2 npt to 1/2 inch nipple fittings. I cut the stock hard lines where stock rubber hoses attach. New rubber hose from cooler fittings to cut hard lines with double clamps.

Any ideas?

Thanks,
JC

 

I played with my tranny cooler this weekend to. I notice and from what I interpreted from your post you put rubber lines onto steel with double clamps. Might I suggest flaring the end of steel lines then clamping, it will give some bite on the id of the hose so it won't pop off under pressure.
From what I read if fluid gets between hose and steel line it makes it easy to pop off. I ended up renting flare tool and flaring the ends. Little insurance I guess for piece of mind.
Also by chance is your hot line going to top of the cooler? Might or might not matter but I would think it would aid in flow going from the top down instead of trying to pump fluid upward.
Also on the rubber lines on the hose I bought said minimum of 3 inch for bend. Is it possible you have a bend that's too sharp and restricting flow?

 

what are the truck specs?

180 isn't bad.. it's right where it should be, actually.. it's dead on if you're using a 180 stat, and even better if you're using a 195 stat..

where did you implement the cooler? upwind or downwind of the radiator?

edited to add:
if i'm not mistaken, the OE route is to external cooler first, and then to radiator.. the principle is to cool it off first- and then to further cool it through the radiator- OR- warm it through the radiator if need be.. too cold of fluid is not good either, and will disallow the o/d to engage.. that is a nice problem to have, no?

I think the OE way of thinking is silly, and I routed to factory cooler, radiator, then additional external cooler back to trans.. I live in a warm environment though, and don't ever have to worry about too cool..

 

I don't recall the return line on my 05 hemi 1500 going to radiator. Both lines on mine ran to tranny.

 

It's kinda hard to see how it's plumbed unless you've had the radiator and cooler removed at some point, but rest assured, every factory rig there is routes through the radiator.. whether before or after the external cooler is the question.. I don't know if that varies, or if it is a standard thing..

 

Agreed, 180* with a full load doesnt sound bad to me either

 

Sorry fellas, the truck is a 2005 2500 crew cab Cummins. Has 170k miles, upgraded from stock transmission, new injectors, smarty JR running SW2, TM2, and TQ4. My dad put a different thermostat in it before I got it. Wanna say its a 190 but not sure.

The new trans cooler is mounted in same spot as stock (in front of radiator, behind cooler). I plan on removing the rubber lines and flaring the stock hard lines. Did not have the tool yesterday. The new cooler did not have any markings on the ports indicating in or out so i'm not sure which line is running to which port. Guess I need to clarify that......

On the way home today the overhead was 88 degrees F. All highway at 65-70MPH. NO LOAD. Trans temp fluctuated between 180-185.

Kicker is I am still leaking tranny fluid on the bottom passenger side corner of the radiator. Thought the stock trans cooler was leaking but apparently it was not or was not the only thing leaking. Guess I need to find the trans line that goes in or out of radiator.

Thanks for all your replies!

JC

 

most auto transmissions route from the pressure line (hot, leaving transmission) to the radiator, and back to transmission (low pressure 'cool' line)..

if there is an external axillary cooler, most often they go there first- then through the radiator, then back to the transmission..

If you live in a warm environment, OR, if you plow or tow/haul a lot, it makes the most sense to route the additional axillary cooler AFTER the radiator, and directly before it returns to the transmission.. it will drop a few more degrees in this manner..

I'm going somewhere with this, though- and this is what applies to your condition..

Find out where it's leaking.. fix that.. know this though: you don't HAVE to route through the radiator.. that is simply a measure the factory uses to maintain a temperature range that is optimum (not too cool, not too hot).. if you're pulling/hauling/plowing or some such, that system of operations is seriously stressed to maintain it's designed purpose..

you can, and if you're working with a rebuilt transmission I'm surprised the transmission shop didn't advise this: either totally replace the radiator exchange core for a brand new one, OR, route the lines to their very own exchanges and don't route through the radiator at all.. two honkin' big exchanges mounted on either side of the radiator does damn near the same trick.. here IS the trick-

mount the first one directly behind the radiator.. it will warm it.. then the additional aux in front of the radiator- it will cool it.. use quick release fittings.. IF, in the winter, you lose o/d due to transmission temperature, all you gotta do is flop the quick releases to where the front one gets the juice first- the back one second.. this way, the one on the back of the rad gets warmer air from the radiator exchange forced through it- and, whallah- it warms it..

if'n it were me, though, i'd be having a talk with that trans shop and having them explain why i've got leaks and why they didn't tell me this..

 

drewactual,

thanks for the reply and info. I bought the truck used from a guy in TN. He told me the tranny was rebuilt by an outfit in Ohio called Firepunk Diesel. I was able to contact Firepunk and spoke with a guy who confirmed it was rebuilt/upgraded. They didnt install it though, the previous owner did. Its supposed to have around 8k miles on the rebuild...

from what I gather my truck has a heat exchanger that the coolant and trans fluid passes through. not sure if it hits the radiator next or the trans cooler in front of rad. I have looked all over the radiator but cannot find a trans in/out. Im guessing it comes from the heat exchanger. Wish I could bypass the heat exchanger due to numerous horror stories about coolant and trans fluid mixing. Thats scary!

Sounds like your idea might work. Im gonna re-read your post and see if I can come up with something.

And oh, I have a 180 Tstat.

Thanks again!!

JC

 

it's a real easy job.. once you've got the parts and pieces, you'll be in and out of there in a matter of an hour- two hours absolute tops.. and you'll have peace of mind that what you're doing is giving your trans longevity..

you're going to need:

2 large exchanges.. I prefer plate style, NOT tube and fin style.. a plate is identifiable as two sides having large tubes running vertical, and smaller usually flat tubes running horizontally, with small fins in between.. a tube exchange has a large tube meandering through it with fins encompassing it.. the fluid moves faster through the tube and fin, and slower through the plate style- the plate style cools more efficiently in this manner..

two large ones will run you somewhere around $40~$50 each..

maybe 12' of 3/8" or 1/2" (depending on what you're rigged to use on your transmissions hard lines) !!!ATF!!! high pressure rated hose.. maybe $20ish

external transmission filter kit.. a spin on filter works best.. will work as both an anti-siphon as well as cleaner of fluid..

enough fluid to fill her up..

hose clamps.. at least two for each junction.. the trick with hose clamps is the heating cycle- once they've been hot a few times, they will hold.. but you need to tighten them after a few cycles..



pull the transmissions hot pressure line and point it toward a bucket.. pull the transmissions cool line and point it toward a bucket.. push fluid with compressed air in the direction the transmission's pump pushes it through the system.. get as much out as you can..

mount the first exchange behind the radiator.. people usually scream at me when I suggest this, but I've had zero issues with the zip-tie style mounting nylons.. Mount the second one in front of the radiator.. you can push the same mounting cables through both, and use eight cables total..

plumb the two together using a section of ATF hose.. double clamp the unions on both sides..

run a stretch of hose from the hot line of the trans to the inlet on the inboard exchange.. double clamp both unions..

run a stretch of hose from the outlet of the outboard exchange back to the engine bay, or to where you are going to mount the external filter system..

mount the external filter system.. I mounted mine on the interior of the passenger wheel well, where there was hefty enough material to support it..

put the line returning from the outboard cooler to the filters inlet (MAKE CERTAIN IT IS THE INLET).. run a stretch of line from the outlet to the trans return line..

fill fluid with about what came out of it..

start and warm truck with it in neutral.. check fluid level.. fill accordingly..

monitor it for leaks every time you approach it for next few days.. after about a week, tighten the clamps again.. don't strong arm them, just snug them up.. look for anything that isn't to your liking such as wet unions, splitting lines, ect..

once you've knocked the bugs out of it, you've got a strong system going for yourself..


optional: instead of using clamps, take the hoses which are cut to length to a place capable of pressing connectors on and have them install a quick release.. if you do this, you can exchange the order of which heat exchange is used first if in the case you're running too cool in the winter.. I wager that won't be a problem, though..

back to your original post: you said you're running 180 and with a 180 stat.. you may simply need to fix some leaking clamps and go about your business.. 180 is pretty dang good.