Tranny cooler question

[HighCard77]

Mounting the thing...just one more issue, don't use those cheap rods that fit between the fins of the condensor (if A/C equipped) & your rad. They will cause leaks down the road. Make-up some brackets and bolt it on. Not sure if already mentioned, but if you don't want your A/C or have a condensor from another parts beast...you can use it as a cooler as well.

 

[VTEK1]

my temp gauge keeps moving between the 210 mark and the 200. Mostly in the winter the truck stays at 200 because the heat is usually on. I noticed last week that when I've been driving the Jeep up to Maine and the oil heats up I start to lose oil pressure and this seems to be creating an increase in the temp. I know nothing about tranny or radiators so if someone could dumd this down for me that would be great. I think the lines themselves are leaking but I'm not totally sure.

 

[MoparManiac]

Just an FYI, a tranny cooler from an early 90s Explorer is stacked plate in design (I believe) and is large/fairly cheap.

I'll get a pic up when I get a chance.

 

[5-90]

my temp gauge keeps moving between the 210 mark and the 200. Mostly in the winter the truck stays at 200 because the heat is usually on. I noticed last week that when I've been driving the Jeep up to Maine and the oil heats up I start to lose oil pressure and this seems to be creating an increase in the temp. I know nothing about tranny or radiators so if someone could dumd this down for me that would be great. I think the lines themselves are leaking but I'm not totally sure.

Despite the long-chain polymers used to increase oil viscosity (thickness) with heat, you're still going to see a decrease in oil thickness as it gets hotter - that's the nature of the beast. A 50-vis oil is usually going to be thinner at 210* than a 30-vis oil at room temperature. When you see something like "10W-30", read that as "10-vis Winter, 30-vis." Meaning: the long-chain polymers used "break down" at cooler temeperatures to make it act like a 10-vis oil (about like auto transmission fluid) when it's cold, and then reform to act like a 30-vis oil at higher temperatures (like when it gets up to operating temperature.) Yes, the 30-vis oil is thinner at elevated temperatures than the 10-vis at room temp, but it's still to your advantage.

The "pressure loss" is simple to explain - as you pump a "thinner/lighter" fluid, you have to do less work to get pressure up. It's also more tolerant of resistance to flow (bearing orifices and the like,) so it doesn't get restricted as much. This is why we have "multi-weight" oils - so they can behave like thicker oils when they get up to temperature, but we have the advantage of having them behave like thinner oils when they're cold (try starting an air-cooled engine with 30 or 40-vis oil during a cold snap, and you'll see what I mean. I used to keep a heat lamp in my Bug back home to heat up the crankcase if a cold snap hit - otherwise, I'd wreck the engine because it wouldn't get oil.)

You're not really "losing" pressure - it's just that the oil flows more easily as it gets hot. This is a fairly difficult idea to put forth simply - I'm doing the best I can - but I hope it gives you more of an idea of what's going on. I'm fairly sure you'll have questions yet, but they'll be a bit more specific now, and they can be addressed in greater detail when you ask. Engine oil chemistry ain't a simple subject...

 

[Muad'Dib]

Skip the radiator/trans cooler. It's a retarded design and just stick extra heat into the engine coolant and slows the cooling process.

I've been running mine that way and I have no problems in the -30 - +100 deg SD weather. You want the trans fluid to warm up let it run for a bit longer.

And bigger is better to a point, area is only part of it, get one with the biggest tubes you can find as well.

In bold is the problem... Just as running hot fluid longer in the tranny is bad, so is cold. The longer you run it in there the more life its going to suck out of your tranny.

I stick to my recomendations.

 

[VTEK1]

thanks for explaining that. I understand how oil works but I was getting worried because the engine seemed to be getting to hot I was thinking about using 10W-40 high mileage. but with the tcm and pcm problem I'm having I'm willing to blame the temp problem on the tcm or pcm messing with the temp sensor. but i did notice that the pressure seems to be lower than normal. sometimes at a stop light it's below 30PSI (just barely) other times it's almost 40PSI???? I know XJ have bad oil sensors but is there something to this????

 

[xjtrailrider]

I think the idea is the other way around.

Trans -> aux trans cooler -> radiator -> trans

Doing this will help keep it from getting too cold in cold weather. Here in california its ok to bypass the radiator, but it would not be a great idea in say .. colorado.

X2, this is how I run mine on the daily drivers. Our winters here in SW VA are mild with mid teens being the coldest we get but in my opinion is the tranny needs some heat in it to operate correctly and help fuel mileage as well. Thick fluid takes HP to turn things in.

On the trail rigs I bypass the rad, I just let the Heeps warm up before hitting the road/trail and take it easy on them until i start seeing 100 degrees on the tranny temp guage. I don't wheel much in the winter time anyway. I like to keep things simple on the trail rigs and keep connections(possible leaks) down to a minimum.