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Medium Truck transmission cooler w/3/4" ports

FellowTraveler

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Up front, I can say, this is overkill, however; I made it fit my radiator support along with AC condenser, and P/S cooler, I will be using a weather front in colder weather.

I reduced the 3/4" NPTF ports to 180 deg. 8AN fittings to SS braided teflon hose to a few 90 deg. fittings from in/out ports of transmission.

Question is; I am running a 48RE high pressure low RPM pump, 30 micron inline NASCAR spec. filter, so should I worry about excessive pressure drop across such a massive cooler, or?
 

Will L.

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If it is same size lines going to and from cooler, the net pressure will be the same.

Larger tube size isn’t ideal however.
The volume will be whatever it is according to the pump. Going from small line at higher pressure into the larger tube size coil allows for expansion which would drop pressure at that point. It would also theoretically drop a small amount of temp when that happens.
Having smaller cross sectional tubing in the coil means more fluid in contact with the tube, and more tube in contact with the air, so more btu removed from fluid. But then as fluid leaves the cooler it gets squished back into the smaller line bumping pressure back up whatever minimal amount of loss there was. The other drawback is the expansion and contraction areas are going to disturb tlow more at those areas and could cause more aeration.

The turbulence is good inside the tubes because laminar flow inside means the same fluid is staying in contact with the tubes aand and exchanging the cooled fluid for the warmer fluid inside that laminar flow means better cooling. That’s why the dimple core radiator tubes are so much more effective. How much aeration it causes -I would think negligent.

The larger volume the cooler has the better it will perform, but a 1 qt, cooler with 100 square inches will do better than a 1qt cooler with 80 square inches.
 

FellowTraveler

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I have been wondering about that, since both in/out transmission fittings are limited to 1/4" NPT.
I bought a flow meter w/0 to 10 gpm scale it has a 250 deg F limit which I suspect is OK with such a large cooler.
Low stall convert has me wondering about internal condensation boiling and steaming out of trans and OD 4x4 vents, higher stalls do boil it off.
I hate the idea of a fluid to fluid torque converter cooler Dodge keeps using on their diesel application transmissions because of internal failures that are quite common in that design...once water or coolant is introduced there goes BIG $,$$$.
 

FellowTraveler

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I suspect I will have to use a weather front in front of the grill the winter in Florida too. Ideally 220 deg. f is needed to boil off any condensation inside the trans case that accumulates over night or on humid days.
 

Will L.

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On all my rigs that had 4l80e temps, they almost never hit 200. Does the 48re always run a lot hotter? A wether front on that is going to block radiator too. Seems to me pushing heat into the engine for sake of removing moisture from trans isn’t worth it. If it is that big a concern, you could add a diverter valve to bypass the awesome MONSTER cooler you added. Want it to heat up just flip the switch, then once achieved flip it back.

I here many people having concern over humidity condensation inside transmission, but if it is that big a concern, why not seal it off like the newer transmissions are? Make the trans dipstick a sealed unit that can withstand vacuum/ pressure. Plumb from the overflow port to an atmosphere expansion tank with a schrader valve like an a/c system uses. Get it running, check fluid to proper level, and hook up the vacuum pump. It will cook off the moisture just like it does the a/c system. Then have it draw airbacm in through any kind of drier and seal it off at zero pressure. Because it is an experimental system, add a basic vacuum/pressure gauge you could see while driving, temporary is fine. Run it hard and see if it can build enough pressure from heat expansion to make any difference. Tank size would determine max pressure achieved, larger tank= lower pressure.
When vacuuming moisture out, low vacuum for long time can accomplish same thing as high vacuum short time, I Don’t think you would need to go anywhere near 20hg
 

FellowTraveler

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I had forgotten to point out, transmission temps rise with in torque converter slippage and that will burn off any condensation, the weather front idea is not written stone.
So a tighter lower stall converter will lower trans temps quite a bit, as does proper running pressures to clutches. I suspect the trans vent is actually a steam vent. I eliminated the pump vent as it is the common way water get into this series trans, I now run top trans case, OD & T-case, diff, p/s, hydro boost vents up high.
The 47/48 RE brought me well within the $10k realm that's with me doing the labor and still a gamble as I went well beyond what most everyone else has for this build.
I do not dismiss the idea of a smaller trans cooler, the current setup was close to the Cummins setup big torque convert heat exchanger and trans cooler up front, I did not want to risk the heat exchanger failing for the inside which is a common issue.
 

Will L.

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On the vent, hummer/hmmwv just uses vacuum hose from transmission, transfer case, differentials (and geared hubs) all tie together to 1 small vacuum line and get their air through the air filter. A simple and low cost modification that makes sense for any offroader or anyone that might have to cross any deep puddle.
 

FellowTraveler

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On the vent, hummer/hmmwv just uses vacuum hose from transmission, transfer case, differentials (and geared hubs) all tie together to 1 small vacuum line and get their air through the air filter. A simple and low cost modification that makes sense for any offroader or anyone that might have to cross any deep puddle.
That's the way, however as you know the fording diverter valve redirects a very small amount of pressure into all those vented components to prevent water ingress. I am looking into the Raycor CCV 4500 to integrate into 3/8" vent system too.
 

Will L.

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That's the way, however as you know the fording diverter valve redirects a very small amount of pressure into all those vented components to prevent water ingress. I am looking into the Raycor CCV 4500 to integrate into 3/8" vent system too.
Yes but only in hmmwvs with the kit. They use whatever crank case pressure there is to pressurize them It also goes to the power steering pump resivour but only when the dwf (deep water fording) switch is on which also disengages the fan clutch. Remember added pressure is bad, you only want it when crossing water.

however on all hummers & hmmwvs even if they don’t have that dwf feature, they still all have the hoses. The idea of the pressure is to ensure no water coming in past worn seals. The concern is that high rpm, they draw a vacuum and having vacuum in gear boxes makes water ingress worse. The fuel tank vent just goes to a small inline fuel filter up high. A person could do the same with all the others and no need of adding pressure imo. The need of a filter is so dust doesn’t plug the vacuum line. It seems once every 100,000 miles replace that little filter is plenty.

the racor is nice. Only needing new filter about every 45,000 is good, but having the indicator is really great. I bough Bobbie Martin’s used provent, wish it had an indicator. I am going to use a small vac/pressure gauge and check randomly. I expect 40,000 mile intervals with it. Are you adding the drain back line and valve? If so, where are you tapping into? I am undecided about adding a port into oil pan vs manual pouring back in. Manual you could see if any moisture collected and separate.
 
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FellowTraveler

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Yes but only in hmmwvs with the kit. They use whatever crank case pressure there is to pressurize them It also goes to the power steering pump resivour but only when the dwf (deep water fording) switch is on which also disengages the fan clutch. Remember added pressure is bad, you only want it when crossing water.

however on all hummers & hmmwvs even if they don’t have that dwf feature, they still all have the hoses. The idea of the pressure is to ensure no water coming in past worn seals. The concern is that high rpm, they draw a vacuum and having vacuum in gear boxes makes water ingress worse. The fuel tank vent just goes to a small inline fuel filter up high. A person could do the same with all the others and no need of adding pressure imo. The need of a filter is so dust doesn’t plug the vacuum line. It seems once every 100,000 miles replace that little filter is plenty.

the racor is nice. Only needing new filter about every 45,000 is good, but having the indicator is really great. I bough Bobbie Martin’s used provent, wish it had an indicator. I am going to use a small vac/pressure gauge and check randomly. I expect 40,000 mile intervals with it. Are you adding the drain back line and valve? If so, where are you tapping into? I am undecided about adding a port into oil pan vs manual pouring back in. Manual you could see if any moisture collected and separate.
You can make your own fording kit to retro to any drive-train...
 

FellowTraveler

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I will soon repaint the beast.
On another note, many performance Cummins guys/gals are dumping the transmissions in newer trucks and going to the 48RE as it has proved to be the strongest of all but the ALLISON.
 
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