TJ Trans cooling ideas

[alosix]

Check this post as it sounds as though Mr. Yates has been there and done that and could save you a lot of guessing and confussion. http://expeditionportal.com/forum/showthread.php?t=14264&highlight=trans+coolers


Donn

Thanks for the link.. Think I went over that a few months ago while starting to formulate my plan.

He seems to have a pretty persistent issue just driving the Jeep around. My Jeep 99% of the time and even towing on relatively flat ground it does just fine. It just tends to have issues dragging the trailer up the sierras.

 

[robert j. yates]

Given the references to my work, I guess I should update my situation.....

I have recently completely cured both my engine cooling and tranny cooling issues. First, I removed the 7 blade Mopar fan and fan clutch and went back to the stock 5 blade fan with a Hayden HD fan clutch. That took care of the engine and it made me comfortable to get rid of my framerail billet style tranny cooler and go to a small stacked plate cooler mounted on the V-support inside the grill. This is mounted in series with the fan driven cooler located under the tub behind the driver opposite of where the stock muffler would sit. With this modification, I have yet to breach 225* in engine temps while towing (with the AC engaged) as well as 200* in tranny temps. My temp guage is connected to my cooler output line on a t just before it returns to the pan. That was the best I coud do without serious surgery on my existing plumbing.


My advice would be to take your tranny cooler out of the radiator and then run separate 2 coolers in series such as I did above. The fan driven cooler is thermostatically controlled so it only operates if temps exceed 180*.

As far as my previous engine issues go.... I beleve the 7 blade fan was not being driven correctly and actually added to my problem by not spinning at the correct speed. The 5 blade fan and heavy duty clutch took care of that and once engine temps dropped, it made my situation with the tranny easier to deal with so if I were you, I would not automatically discount getting a stacked plate cooler behind your grill... unless you have something else planned for that space. In that case, FYI... I also have a power steering cooler behind my grill so there is space.

Thanks for the link.. Think I went over that a few months ago while starting to formulate my plan.

He seems to have a pretty persistent issue just driving the Jeep around. My Jeep 99% of the time and even towing on relatively flat ground it does just fine. It just tends to have issues dragging the trailer up the sierras.

 

[alosix]

Robert,
thanks for the reply.

I knew I read your report somewhere before since that fan swap sounded very familiar.

I like the fan driven one under the back, that might be the easiest one for me to plumb in right now. Tempted to put a thermostatic valve in to allow it to go through the rad until its warm.

Granted the stacked one in front of the rad might be the most cost effective solution.

At least I don't have AC to worry about

 

[robert j. yates]

I did a short write up on the 7 blade fan issue on JeepForum several months back - I just never updated anything here. Good luck with your install.

 

[lexwoody]

Try this site for trans cools. Remote with electric fans and non remotes.

http://www.flex-a-lite.com/auto/html/oil-coolers.html

 

[86cj]

I addressed this issue last summer on my LJ..

http://www.expeditionportal.com/forum/showthread.php?t=30394


We just did not have a hot summer this year so a real test is yet to come. It seems as though it helped in the deep sand though.

I like the B&M coolers with a fan, but I chose not to "make" it fit in front of the condenser, it's tight.

I think a Mopar 7 blade HD clutch fan was put on my company truck when it's aux electric fan failed. It is loud and engaged more often than not and the power surge as it quits is very noticeable.

 

[PhulesAU]

I addressed this issue last summer on my LJ..

http://www.expeditionportal.com/forum/showthread.php?t=30394


We just did not have a hot summer this year so a real test is yet to come. It seems as though it helped in the deep sand though.

I like the B&M coolers with a fan, but I chose not to "make" it fit in front of the condenser, it's tight.

I think a Mopar 7 blade HD clutch fan was put on my company truck when it's aux electric fan failed. It is loud and engaged more often than not and the power surge as it quits is very noticeable.

Clean looking install, How much of the grill area did you have to remove to get it in there?

 

[86cj]

I did not have to cut anything because I mounted the fan and trans cooler side by side, leaving a little room around them.

The area is tapered with more thickness available at the top than the bottom. I was thinking of offsetting the sandwiched fan and cooler a little and it might fit the taper, that's why I did not buy the cooler w/fan B&M sells.

I think a sandwiched cooler w/fan will fit and would not rule it out in the future, but some trimming of the back of the 7 slot grill would be required. I just decided to try the easy route for now.

I used some 1/4" flat stock to make the whole mount, gaining a little room over the factory round tubing full of rusty water.

 

[alosix]

To bump and old thread.

Changes so far in the cooling build.

Axles:
4.10s seemed to be making it work to hard. Swapped to 4.88s. While I was in there I threw in an Eaton e-locker in the rear. Finally locked at both ends

Cooling:
New Radiator. Pretty boring aluminum one from Northern. Also added an Aux trans cooler in front of it.

The old rad was in some pretty bad shape.

Just finished up the front gears and rad work. Going to put some miles on it this week then tow the trailer up to Tahoe City next weekend. Here's hoping its a bit better.

 

[ntsqd]

......

I like the fan driven one under the back, that might be the easiest one for me to plumb in right now. Tempted to put a thermostatic valve in to allow it to go through the rad until its warm.
........

My bad, just now saw this. Those t-stats that I linked are not "or" devices, they are "and" devices. If that makes logic sense. They are intended for engine oil applications and when below their opening threshold will bleed a small amount of fluid through the cooler to purge any air. Once the temp reaches ~160*F they start to include the cooler in the flow path. By ~180*F the cooler is fully included and not by-passed. Can use them to add a cooler when needed and by-pass it when not needed.

So if you used a cooler with it's own thermostatically controlled fan you could build a staged response system. At 160*F the t-stat starts to open and bring the aux cooler on-line, at 180*F it is fully on-line but no fan running, at 2XX*F the fan comes on. This staged response will make for a more consistent fluid temperature than turning on everything at one temperature and avoid the possibility of thermally shocking the system.

I would not exclude the radiator heat exchanger unless the vehicle will only be operated in warm to hot ambient conditions. Just like an engine, the trans has a design minimum operating temperature. Operating it below that temp will cause it harm. Keeping the radiator heat exchanger in the system will allow the engine to warm up the trans as it is warming up.

 

[alosix]

My bad, just now saw this. Those t-stats that I linked are not "or" devices, they are "and" devices.

No prob.. I figured that out after going over the specs for them a bit.

For now, its just an extra cooler in front of the rad, no fan.

I didn't realize just how bad of shape my radiator as in until I was working on the front diff and started taking things apart. May 1/2 of the fins on the backside were damaged/missing. Very flakey also. Inside looked a bit clogged as well.

FWIW, you can feel the difference in air moving when the fan clutch locks up from old rad to new. I guess after 13 years and 140k miles it was really time for a new rad.

The Jeep has really liked the 4.88s BTW. The 35s and AW4 with that gearing seems just about right. It'll still easily cruise 75-80 if wanted and now doesn't fight me going over the little bridges out here on 101.