questions after tranny cooler/gauge install

so after frying my tranny recently, i just put in a new(er) tranny in my cherokee (95XJ,4.0L,AW4,NP231, 3.55gears w/31's). i also installed a 18,000GVW tranny cooler BEFORE the radiator (tranny--cooler--radiator--tranny), and a new temp gauge for the tranny.

i mounted the tranny cooler in front of the radiator on the passenger side thinking that the engine fan would help pull air through it. so all i have is the tranny cooler and the radiator. no A/C or anything else.

well i noticed that since i've done that, my coolant temp occasionally will go slightly above 210 which it never did before. any ideas???

and the tranny seems to ride happily at 170-180ish while i'm moving, but after a decent drive (either long haul through the city, or highway driving), when i come to a stop and sit there for a bit, the temp starts going up to around 210, and occasionally up to 250. i'm not happy with that at all. why would it be going so high while sitting still with the additional cooler in there now???

is there something i might have overlooked, or should i install an additional PUSHER fan in the front grill, or possibly do the electric fan conversion so i can have it running while sitting still??? i'm trying to find some answers on this because i would like to get this situation corrected before my next wheeling trip.

oh one more question i just thought of...........if i have a temp sensor in the OUTGOING line and the RETURN line, which temperature should i be more concerned about??? the return line since that's what the tranny will be working with, or the outgoing line since that's what the tranny did???

Is your new transmission rebuilt? Has it been fully broken in yet? If so, then it may still be working out a few bugs.

I'd place the temp sensor in the outgoing part of your lines; you'll want to know what temperature the tranny is at, not what temp the fluid has been cooled to.

An electric fan should help with your problem somewhat; it'll spin at a constant speed and pull more air than your mechanical fan will at low RPM's. You could relocate it to the other side (if you have the aux electric fan) and wire a switch to the fan in order to provide a constant flow of air over it.

One reason your engine temp might be going up is the additional heat load, and slight reduction of airflow caused by the new cooler. It shouldn't be too much of a worry; both of my 4.0's ran at 210 when healthy. If it pops above it, then the auxiliary electrical fan popped on to help out (usually in summer.) As for the tranny temperature, I don't know what the normal operational temperature range is. I do know that the AW4 is known to run a little hotter than most transmissions.

HTH!

does anyone know the normal operating temp of an AW4 with and without a cooler?

I have my temp gauge to the feed to the cooler. Prior to installing eth aux cooler, I drove it around for a bit in the summer to see how hot she would get.

If I drove nice, the trans temp only hit around 160-180*. If I drove aggressive, the temp would get closer to the 210-220* mark.

Once the cooler was installed, the temps dropped to around 140* when driven nicely. Aggressive driving gets it to about the 160-170* mark.

I believe you are supposed to run the hot line into the rad, then the aux cooler, and back to the trans. The rad will actually add some heat to the cooled fluid.

I mounted mine at about half way between the mech fan and the aux fan. My AC took a dump and I never got around to fixing it, so I just disconnected the plug to the compressor and wrapped it in tape. When it gets warm offroad, I slide the HVAC to defrost or AC and the fan kicks on.

the tranny that i got has around 95-97,000miles on it.


i know the 4.0's run at 210. mine always has. but mine would consistently stay right at 210. not above. and that was with the a/c condensor in there. now i removed the a/c condensor and installed a tranny cooler, so i don't see how the amount of airflow changed.

as far as operating temps, i know that auto's in general are healthy between 150-190. anything over 220 starts hurting them.

and the reason i mounted the cooler before the radiator was that it would prevent it from undercooling during the winter. i figured that during the winter the radiator would warm it back up, and during the summer the cooler would bring it down, and the radiator would keep it just like it was before i added a cooler. is there any major downfall to that way of thinking???

did you use any kind of spacer between your trans cooler and the radiator?
I'd venture a guess that you're limiting the airflow to the radiator now, and that's why you're seeing increased temps.

My guess is this, by adding any cooler in front of your radiator, it will cause some increase in your water temp, especially when not moving. Think about it, you had added a device that radiates heat. Now any air blowing through that is now hotter then before and you are blowing this hot air into the radiator. No different then if you raise the outside air temp up. You also decressed airflow by adding more restriction in front of the radiator, just like putting a piece of cardboard in front of the radiator.

As for putting your tranny cooler before the radiator, any cooling you do with the tranny cooler is being offset by whatever the water temp is. The water will try to raise the outgoing temp closer to itself. That is why you typically want it after the radiator, so it will cool it down from the tranny and radiator temps. I understand your idea and in really cold climates it makes sense. My best bet is even if the radiator output is at 210*, even a 60* drop (which is very unlikely) from the tranny cooler still only puts you temp at 150*, which is fine for the tranny.

My .02 worth. YMMV

the only spacer that i have between the cooler/radiator are the little foam spacers that came with the tranny cooler. i'm guessing that there is maybe 1/8-1/4" between them. somebody suggested i increase the space to
1/2-3/4".

i guess i'll try to move the cooler after the radiator then. hell if i do it right, i can use quick disconnects, and if it does get extremely cold again like it did this winter, then i can just switch the lines around.

I have my coolers on all 4 of my XJ's on the drivers side. I have not seen any increase in engine temp. I'm running the Hayden 30,000 GVW units.

I'm running temp guages on all 4 also, and they all run 160-170 on a hot summer day towing(return line temp).

The best place for the sensors is both before and after the cooler and put a toggle(double pole, single throw) in line to switch it. That way you can check the efficiency of your cooler. I'm running that set-up on one of my XJ's and on the others I got cheap and only put it on the return lines. I just really want to know that the oil going back in isn't cooking and will help cool the tranny.

I am also running the same circuit as you, tranny output-cooler-radiator-tranny input. I like a little heat back into the tranny on cool days.

i'll have to check it again and drive it for a couple days before making any changes. apparantly there was some air in the system after putting the new tranny and cooler/lines in. after driving it a bit, i noticed yesterday that i was a bit low. so i topped it off with about 2qt. somehow i got a feeling that may not have helped the situation. i'll report back.

is it the upper or lower line that returns to the tranny? Im installing a cooler tomarrow and havent had a automatic vehicle in some time so I forget

the return line to the tranny is the bottom one on the radaitor.

crank up and put it in drive for about thirty seconds, feel the lines the hottest one is the feed the coolest the return

skim, that is what I thought but on my 89 aw4 the bottom line is the feed

I got my info from here, it for worked fine for me when I installed my tranny cooler.they both say the lower line. http://www.4x4trailhunters.com/article.php?id=21
http://www.jeepin.com/features/trannycooler/index.asp

I know, I followed the same articles, but
test the line temp. mine at least indicates the lower line is feed and upper is return. doesn't make a difference for me since I completely bypassed the tranny cooler anyway. I swapped in a B&M unit I got from ebay, it's the small one ( 9800 BTU) but seems to work fine on road, might just use my a/c condenser though, once I put a therm to it.

weard

FWIW, I found the same situation on my 97 last night while installing a cooler. Mine still had all the factory steel/swaged rubber lines and quick disconnects. I cut the rubber section out of the return line because I wanted to run the aux. cooler after the one in the radiator. I hooked up the aux. cooler to the steel line running back to the transmission and then noticed that the other part of that steel line ran to the top of the radiator. Since all the articles I had read indicated that it was supposed to run to the bottom I decided to test it even though I pretty much knew that I was working on the return line. There's really no way that the line out and the return line positions on the transmission would change. Anyway, I connected a piece of hose to the line coming from the radiator cooler to feed in to my new aux. cooler and put it in a can. I ran the engine for a few seconds and found about a cup and a half of trans. fluid in the can and nothing coming out of the open end of the new cooler. So, if you are installing a cooler, forget about what line is where on the radiator and just assume that the rear port on the AW-4 is the return line.

The guy that does the trannsmisions for my barracuda has always told me to run the cooler before the radiator. Since he does that for a living i took his word on it and it works good, I also run the guage on the hot side as it tells you whats happening right then.

I have a factory cooler on my XJ, I need to get out and look and see how it is plumbed out of curiosity. I plan on makeing the factory cooler a PS cooler and putting a larger aftermarket cooler on for the trans.