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Discussion Starter #1
Hello all,
So I've just purchased a 2008 jeep commander with the hemi and of course I have some questions.
One of the main reasons I bought the jeep is to tow my camper. I'm gonna install a break controller and the jeep has the tow package from factory.
My question is, do I have to install an additional tranny cooler?
The trailer weigh's in at 2900lbs. I'll round off to 4000lbs once loaded which is more than I will ever load it with but I just don't want to destroy my transmission. I live in a very mountainous area so I just want to be sure.
Thoughts? Thank you
 

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Does you vehicle have the Factory Tow Package, or was a tow hitch added later?

The Owners Manual will answer most of your towing capacity questions.

IIRC (which means take this with a grain of salt, confirm it), the Factory Tow Package did NOT make any cooling upgrades to the vehicle, that even base form the Commander has excess cooling capacity. The Tow Package upgraded the rear suspension to handle the loads.

Also go through the maintenance schedule and towing requires you to use the severe duty maintenance schedule, which will require you too change trans fluid regularly. Do it regularly and use the Correct/Certified ATF, NOT just any old ATF.

Best thing you can do to keep your trans alive is too install a trans temp gauge and monitor it and intervene if temps get to high, to bring the temps down.

The Hemi has a Hydraulically driven fan. The PS system supplies the hydraulic fan. The O.M. will tell you to use only a very specific PS fluid from the Dealer. There has been posts about cooling problems with Hemi's and it turns out to be the hydraulic fan wearing out and they are incredibly expensive to replace. So, I think a wise step would be to replace PS fluid regularly (even though the O.M. says its NOT necessary) and only use the superior PS fluid recommended in the O.M.

Replacing Power Steering fluid is easy, with the engine off and the front wheels up on jackstands, you disconnect the ps return line to the reservoir and route it to a bucket. Turn the steering wheel lock to lock will pump the fluid out of the system and into the bucket. Reconnect the line and fill with new fluid and turn steering wheel lock to lock to pump it through and get the air out.
 

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Discussion Starter #3
I'm planning on doing the PS fluid this weekend.
Yes the jeep came with factory tow package. I know it's rated for 7200lbs towing cap but I just want to know if I need to add an additional cooler with what I plan to do. I will be changing all the fluids but one weekend at a time, lol.
 

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I'm planning on doing the PS fluid this weekend.
Yes the jeep came with factory tow package. I know it's rated for 7200lbs towing cap but I just want to know if I need to add an additional cooler with what I plan to do. I will be changing all the fluids but one weekend at a time, lol.
Honestly I would install one, as well as a trans temperature gauge for peace of mind.
 

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The NAG1/W580A has an internal temp sensor, I don't know for sure, but I think the 545RE has one also. The Hemi would have the 545RE trans. There are OBDII devices that can let you read the trans temp from the internal trans sensor. Some are even Bluetooth device that plugs over the OBDII D connector and connects with your smart phone to read info from the car on your smartphone. So that is one option, but all the OBDII scanners get confusing and the advertising way over promises on their capability, very few people are happy with what they bought, thinking they would get more than got.

The best place to install a trans temp sensor would be the outlet line to the trans cooler, that would be the hottest fluid. Problem is, the Commander trans has funky connectors and limited room on the trans lines, its really hard to improvise something to splice in a trans temp sensor.

I installed my trans temp sensor in the pan.
 

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Discussion Starter #7
Alright so it looks like I'll be installing a tranny cooler. Now for my next question.
I know that you can't over cool a transmission but what I want to know is what's the minimum cooling capacity?
I've seen some advertised at 9800btu all the way up to 45000btu.
What do I really want for my application?
So far I've decided to go with a "plated dual stack" as this is the most efficient design.
I'm considering a b&m unit that says it's rated for 29000btu.
Can someone shed a bit more light on this?
Also, how is it to install one of these on the hemi? Real pita?
Cheers
 

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Not to contradict my Commander brothers above, but I was under the impression the Hemi's with factory tow package, DO have a transmission cooler. ...This excerpt from the factory service manual ---
COOLER-TRANSMISSION​
DESCRIPTION​
The automatic transmission/power steering cooler assembly is located in the front of the A/C condensor and behind the front fascia. The transmission cooler is a heat exchanger that allows heat in the transmission flud to be transferred to the air passing over the cooler fins.​
The transmission oil/power steering cooler assembly is equipped with quick connect fitting for the transmission oil and power steering lines.​
The transmission oil/power steering cooler is serviced as an assembly.

---The reason I know this is because I'm about to replace the lines because mine just started leaking at the crimps.

BTW -- I regularly tow a 5000lb boat (see my profile pic) with tandem axles through the mountains and have never had an ounce of issues with the Commander or Hemi... I don't disagree cooling is better and Mongo/Luckyse is right about a trans temp guage would be an excellent addition and always stay current on Mx and Fluids. Not sure if you would need to add an additional cooler on top of the one from the factory...
 

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Not to contradict my Commander brothers above, but I was under the impression the Hemi's with factory tow package, DO have a transmission cooler. ...This excerpt from the factory service manual ---....
Your are correct, you misunderstood what we said before.

All Commanders have transmission coolers, just about every car made today with an automatic transmission has a cooler.

Most Factory Tow Packages upgrade the transmission cooler to higher capacity one for the heat created by towing.

The Commander's Factory Tow Package does NOT upgrade transmission cooling (I believe, I might be wrong). Because the base model trans cooler is already high enough capacity.
 

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Discussion Starter #11
Either way I've already ordered the cooler and it will be that little bit of added insurance. Better safe than sorry.
What tranny fluid should I use? Can I get ATF+4 in a synthetic?
 

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ATF+4 is synthetic.

I've heard people say ATF+4 is semi-synthetic, I "think" because it uses Group III base stock oil, while most only consider Group IV base stock as real synthetic.

ATF+4 is perhaps the highest quality most durable ATF you can find on the store shelfs, the few better would be the exotic synthetics like AMSOIL.

I have used AMSOIL Signature Series Multi-Vehicle ATF, It is NOT certified/licensed as ATF+4, so they can't put the name on the label, so arguably it is NOT the proper fluid to use, since it is NOT recommended. But AMSOIL says its meets exceeds all the specs of ATF+4, I and others have used it in Chrysler Transmissions and never had a problem.
 

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Discussion Starter #13
Alright then I'll use ATF+4.
I want to change the 2 filters while I'm in there so do you think that if I get 2 gallons that should give me enough to finish the job?
Thank you
 

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Your Owners Manual (OM) should state the fluid capacity of the trans, both total and for just an pan and filter change.

Its usually 5-6 quarts for dropping the pan and changing the filters, but I have the W5A580 so I may be off for the 545RE that is used with the V8's.
 

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Discussion Starter #15
Thank you sir and one last question.
Any tips for dropping the pan and changing the filters? I read somewhere that putting the inside filter might be a bit tricky. Something about the seal if I remember correctly.
Thanks again.
 
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