Do Ranger auto trans run hot?

[Otis413]

I was reading on another Ranger Forum about auto trans when someone mentioned that the poster should add a second (oem) trans cooler while he had his truck apart because "Ranger automatic transmissions run hot".. New info to me, if true, I looked around here on RS and didn't find anything about this being a problem, but, while I have my '03 apart (4L SOHC V6, 5R55E, 4x4, 4.10:1 gears) might be a good time to add another cooler. I do tow some, have a car dolly and a 5' x 10' utility trailer (firewood mostly).

Opinions? I have an extra cooler on my parts donor, and can make my own brackets, also thinking about adding an in-line spin on filter (off my old Dodge).
Thanks for any input!

 

[MikeG]

Sounds like BS. The 5r55e in my 97 lasted 20 years and well over 250K miles with the stock trans cooler, and there were times I used it pretty hard.

 

[Dirtman]

Every automatic transmission should have an extra cooler. Period. The stock "thing" is really not even a cooler, it's a warmer. It runs at radiator temps so it can't spill off much heat when the radiator is already at 160+ degrees.

The 5r55e doesn't really run hotter than any other transmission but it is by no stretch of the imagination a stout trans. Keeping it cooler will substantially increase its longevity.

 

[DILLARD000]

...add a second (oem) trans cooler
...have my '03 apart (4L SOHC V6, 5R55E, 4x4, 4.10:1 gears)
...might be a good time to add another cooler.
...tow some
...make my own brackets, also thinking about adding an in-line spin on filter
...Thanks for any input!

Doing simular TransCooler modification on my 2001 V6~4.0L~SOHC+5r55e.
Tranny is original with 240kMiles now, but runnning strong.
Tranny temps run from 160f cold days to 190f hot days mountain roads with stock TransCooler, via OBD2 with OBDLink MX+ & Phone.
Turning 1st FactoryOE TransCooler 90degrees, bolt to left frame in front of AC Coil behind grill, hose barbs pointed right center.
Mount 2nd FactoryOE TransCooler MirrorImaged on right frame in front of AC Coil behind grill, hose barbs pointed left center.

5L2z-7a095-a - Google Search

0i375 HoseBarbTees in between the 2 TransCoolers, so they're hose connected in parallel.
Two 8" Fans with 2 TempSwitchControls mounted on front of each TransCooler; looking to set TempSwitches at ~160f & ~165f.
Plan to disconnect\bypass ATF lines to+from TransCooler\Heater in left Radiator tank, hose directly to TransCoolers behind grill.
Hope to lower average Tranny temp by 10f or more.
Good luck & keep us posted on your modification.

 

[Otis413]

I think I'll go ahead and do this, I do some heavy towing (occasionally) and everything else being equal I don't think it could hurt.

Speaking of oil coolers, I noticed while we were swapping motors in my bro-n-laws '01 Explorer Sport that it has an actual power steering cooler (about half the size of the common Ranger trans cooler) instead of the usual U shaped pipe mounted on the rack. It's the only one I'v ever seen.. This got me thinking, I have a homemade front skid plate that will prob block some air to the rack and its cooler, I might go ahead and change/move that while I'm at it.

 

[Dirtman]

I had a 92 S10 with every heavy duty option available. It had a massive power steering cooler. That is one thing I never really understood, I've never experienced a power steering system overheat even with oversized offroad tires.

Can't hurt though, power steering still uses ATF and ATF breaks down extremely quick when overheated which is why coolers are a must on automatics. I think at 230? Degrees ATF essentially ceases to function and just turns to black goop.

Your trans should run about 165-175 which is optimal operating temp. It has a thermostat just like the engine that controls flow to the cooler so dont be surprised when you dont see the fluid temp ever go below that, it simply means the thermostat and cooler are doing their job to maintain the proper temp.

I would still keep the factory "cooler" and just run the second cooler in line with it. The factory cooler will help get the fluid warmed up faster on cold days.

 

[Shran]

The closer you can keep it to normal operating temp, the better. I think having either an additional cooler or a much larger single cooler is mandatory with a Ranger auto. It's great that you have 4.10 gears too, that takes a lot of load off the trans.

 

[MikeG]

I won't argue that heat kills ATF. That is a fact.

But.... auto transmissions started lasting a LOT longer, once lockup torque converters became common. The 'slip' in the transmission is what generated heat, and a lot of it. Lock up the torque converter, and you get rid of a lot of heat (inefficiency). As well as get substantially better gas mileage.

Granted if you tow or haul a lot in hilly areas, then yeah the torque converter may not stay locked all the time. I've always run thermostats at the cooler end of the scale, because it gets HOT in central Texas in the summer. Not as hot as Arizona or a few other places, but when it's 100+ (F) it is HOT and heat transfer efficiency of the radiator, any radiator, goes way down.

5r55e transmissions mostly die, or get severely wounded, from blowing out the gasket between the valve body and the rest of the transmission (from what I have read). There are a ton of TSBs on that and similar issues. Why mine didn't, I have no idea, because I beat it like a red-headed stepchild, using it for a work truck. Enough to kill the rear springs. Not recommended, but that's what I had to do at the time. That or not eat.

I put a drain plug in mine and every oil change, I dumped the trans pan and put 4 more quarts in it. Maybe not needed, but that's what I did and I'd guess it lived longer due to that. Just a thought. You'll have to re-plumb the cooler lines if you don't want it to run through the radiator, but probably not a huge deal in the grand scheme of things.

Just a few thoughts.

 

[19Walt93]

In sub zero weather there is such a thing as too cool a transmission, an add on cooler should have a thermostatic by pass to allow the transmission to warm up. Any thermostat in a vehicle controls the minimum temp, not the maximum, that's controlled by cooling system capacity.

 

[Dirtman]

In sub zero weather there is such a thing as too cool a transmission, an add on cooler should have a thermostatic by pass to allow the transmission to warm up. Any thermostat in a vehicle controls the minimum temp, not the maximum, that's controlled by cooling system capacity.

The 5r55e has a built in thermostatic switch to control flow to the cooler. Which is why even with a secondary cooler you'll never see the temp (once warmed up) go below the set temp which I believe is 165. Mine has a rather large auxiliary cooler and always stays right around 165-170 no matter what. But like you said, this doesn't do anything to stop it from over heating, only a big enough cooler can do that.

 

[ford4wd08]

So this brings me to a question. Is the routing through the radiator considered a cooler?

My B2 has it routed through the radiator, which could serve as heater in cold weather, and a cooler once operating temp is reach.

I also have a factory external cooler that is mounted in front of the condensor for the AC behind the grille. I do plan on installing a larger one of those, which I have already purchased.

 

[Dirtman]

So this brings me to a question. Is the routing through the radiator considered a cooler?

My B2 has it routed through the radiator, which could serve as heater in cold weather, and a cooler once operating temp is reach.

I also have a factory external cooler that is mounted in front of the condensor for the AC behind the grille. I do plan on installing a larger one of those, which I have already purchased.

Both... the integrated radiator cooler is obviously only going to allow the trans fluid to cool to the temp of the radiator so it keeps the fluid warm but does still spill of some "excessive" heat. Some people plug and bypass the radiator lines but think its worth keeping the radiator cooler intact when adding an aux cooler.

 

[ford4wd08]

Both... the integrated radiator cooler is obviously only going to allow the trans fluid to cool to the temp of the radiator so it keeps the fluid warm but does still spill of some "excessive" heat. Some people plug and bypass the radiator lines but think its worth keeping the radiator cooler intact when adding an aux cooler.

So... in theory it is pretty safe to install a larger cooler than stock when you leave the radiator lines hooked up as you have a smaller chance of overcooling the trans fluid.

 

[cbxer55]

3.0 with a 4R44 I believe. Anyhow, just changed the trans fluid and filter last Tuesday. After 10 years, it was still bright red. No evidence of overheating at all. I changed it the first time in 2010.

In May, did my 4.0 Mustang with a 5R55. I bought it in November 2019. Have no idea if the owner ever changed it, but it was ugly on draining. Kind of brownish, bad smell. I see the cooler lines for my Mustang, on the passenger side, they run straight up to a cooler sandwiched in between the radiator and the ac condenser. No evidence they go to the radiator at all. No fittings on the radiator for hoses. The lines were not scary hot at all after driving it 60 miles on the highway. The fluid was drained again in October to swap the solenoids trying to get to the bottom of a P0741, Torque Converter Clutch Locked Off, which only happens at in town speeds in OD. At highway speeds ,it never happens. Anyway, after several thousand miles between May and October, the fluid was still bright red.

Did my Lightnings trans last Monday. After 10 years in a 4R100, it was bright red.

 

[Dirtman]

So... in theory it is pretty safe to install a larger cooler than stock when you leave the radiator lines hooked up as you have a smaller chance of overcooling the trans fluid.

On a 4r/5r you can add as big of a cooler as you want because no matter what the fluid flow to the cooler is controlled by a thermostat. It will always keep the fluid at the minimum temp set by the thermostat and only allow fluid to flow through the cooler when it reaches that temp. (Same way the cooling system on the engine works). I do not know if the A4LD has a thermostat switch.