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  #13  
Old 08-23-2013, 08:29 AM
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Re: 2006 WK Towing Upgrades

I am in agreement with greenwayer on this one, the W5A580 is a car transmission and if you do the 3:73 swap you will need to reprogram the TCM so that the trans will shift properly. there was a post a while back were someone did the 3:73 swap and had to have it reprogramed because it threw the truck in limp mode
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Old 08-23-2013, 08:32 AM
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Re: 2006 WK Towing Upgrades

on a side note I have towed a 3800 lbs car back to the barracks before and the truck didn't even notice it, but I have a extensive mods list on my engine alone that's about to get bigger in the near future
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Old 08-23-2013, 10:21 AM
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Re: 2006 WK Towing Upgrades

I appreciate the feedback. The automotive industry typically designs transmissions on two criteria: loading and torque input. The NAG was designed as a 5 speed automatic transmission for a variety of automotive applications. It is not a weak transmission and is quite stout for a light duty auto.

The NAG uses two speed inputs into it: Engine RPM and Wheel Speed. If you were to change the differential gearing, it would alter the ratio between those two inputs and would flag a code and most likely put the trans into "Limp Home" mode. This would not cause damage mind you.

I understand that the calibration would need to be revised, and that is why I would use the Hypertech which has the ability to correct for gear changes.

I am going to go forward with the collection of parts and go from there. Has anyone confirmed whether or not the 4.7L HD cooling package (Shroud and Fan w/ clutch) fits the 3.7L engine? I think it does from what I have found, but just curious....

Cory

BTW: I see you are stationed at Fort Campbell? If so, thank you for your service.
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Old 08-23-2013, 10:52 AM
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Re: 2006 WK Towing Upgrades

Quote:
Originally Posted by Strongjeff View Post
I am in agreement with greenwayer on this one, the W5A580 is a car transmission and if you do the 3:73 swap you will need to reprogram the TCM so that the trans will shift properly. there was a post a while back were someone did the 3:73 swap and had to have it reprogramed because it threw the truck in limp mode
However after doing some further searching I have found the diesel 3.0 uses the same w5a580 transmission and can tow 7400 lbs which is actually 200lbs more than our 545rfes are rated to do. Is this just because the diesel produces so much torque at the low end? Whereas the gas engines would have to hold a much higher rpm to produce the same torque?
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Old 08-23-2013, 10:59 AM
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Re: 2006 WK Towing Upgrades

Quote:
Originally Posted by CumminsTrader View Post
I appreciate the feedback. The automotive industry typically designs transmissions on two criteria: loading and torque input. The NAG was designed as a 5 speed automatic transmission for a variety of automotive applications. It is not a weak transmission and is quite stout for a light duty auto.

The NAG uses two speed inputs into it: Engine RPM and Wheel Speed. If you were to change the differential gearing, it would alter the ratio between those two inputs and would flag a code and most likely put the trans into "Limp Home" mode. This would not cause damage mind you.

I understand that the calibration would need to be revised, and that is why I would use the Hypertech which has the ability to correct for gear changes.

I am going to go forward with the collection of parts and go from there. Has anyone confirmed whether or not the 4.7L HD cooling package (Shroud and Fan w/ clutch) fits the 3.7L engine? I think it does from what I have found, but just curious....

Cory

BTW: I see you are stationed at Fort Campbell? If so, thank you for your service.
Why not buy an shr or paramount transmission? Those things are quite strong and will likely have less problems. Remember with your trans cooler you are cooling the fluid but if enough of the fluid doesn't reach the tranny in time there is nothing you can do. Atleast look in to getting a better valve body.
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Old 08-23-2013, 01:41 PM
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Re: 2006 WK Towing Upgrades

To answer your posts a couple things to remember. The first is that it is the combination of components/systems that dicate what a vehicle can tow not just power. Obviously the transmission is rated for way more than the factory 3.7L V6 rating of 3500 lbs. One point to make is that if you research more, you will find that identical WK's that use the 4.7L V8, but one wasn't factory equipped with the tow package (the HD fan assembly that uses both electric and mechanical fan) is also only rated to tow 3500 lbs. Now if you add the upgrade kit from Jeep for that cooling system, it is now rated at 6500 lb towing capacity. The trans is not the weak linkage.....

I am not familiar with the mods you listed, but can look into them. Either way it is a system approach to make the vehicle more capable and reliable with towing.

Cory
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Old 08-23-2013, 01:48 PM
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Re: 2006 WK Towing Upgrades

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Originally Posted by greenwayer View Post
Why not buy an shr or paramount transmission? Those things are quite strong and will likely have less problems. Remember with your trans cooler you are cooling the fluid but if enough of the fluid doesn't reach the tranny in time there is nothing you can do. Atleast look in to getting a better valve body.
I forgot to mention that I don't understand your logic regarding the cooler and fluid "making it to the tranny in time.."? Obviously if you add addtional lines and cooler, you are increasing the fluid cavity volume and you would need more transmission fluid to compensate for the additional volume. The system will bleed itself of air, and will be a solid fluid column. The factory cooler and lines don't just sit there empty.....

As far as the VB is concerned, I have modded tons of transmissions over the years from GM, Ford, and Chyrsler making changes to the valve body, accumulators, torque convertors, etc... when needed either for performance or reliability. As far as the NAG goes, if it is setup and rated for 7400 lbs towing, most likely the VB is setup in such a way to provide more than apply pressure to the clutch packs under its operational range. This is my wifes daily driver, not our hot rod. I do not wish to make it shift harsher or later when unloaded.

I have the Mercedes training material on the NAG and looking at some things right now. In the end, to me the trans is not anything to really worry about.

FWIW...

Cory
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Old 08-23-2013, 09:04 PM
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Re: 2006 WK Towing Upgrades

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Originally Posted by greenwayer View Post
However after doing some further searching I have found the diesel 3.0 uses the same w5a580 transmission and can tow 7400 lbs which is actually 200lbs more than our 545rfes are rated to do. Is this just because the diesel produces so much torque at the low end? Whereas the gas engines would have to hold a much higher rpm to produce the same torque?
this is a sound theory, in the sense less rpm will generate less heat within the eng/trans. and increases longevity. heat is a major player in why many trans go bad
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Old 08-23-2013, 09:08 PM
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Re: 2006 WK Towing Upgrades

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Originally Posted by CumminsTrader View Post

I am not familiar with the mods you listed, but can look into them. Either way it is a system approach to make the vehicle more capable and reliable with towing.

Cory
a few things I have done to the 3.7 are one off or hard to get unless your looking in the right direction. like the jba headers im running, they are for the libby but I have found they bolt right up. they have become hard to find as they been discontinued by jba back in 2011.

and I thank you for your appreciation for what I do, I don't hear it as often as I like to
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Old 09-17-2013, 08:53 PM
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Re: 2006 WK Towing Upgrades

Quote:
Originally Posted by CumminsTrader View Post
I forgot to mention that I don't understand your logic regarding the cooler and fluid "making it to the tranny in time.."? Obviously if you add addtional lines and cooler, you are increasing the fluid cavity volume and you would need more transmission fluid to compensate for the additional volume. The system will bleed itself of air, and will be a solid fluid column. The factory cooler and lines don't just sit there empty.....

As far as the VB is concerned, I have modded tons of transmissions over the years from GM, Ford, and Chyrsler making changes to the valve body, accumulators, torque convertors, etc... when needed either for performance or reliability. As far as the NAG goes, if it is setup and rated for 7400 lbs towing, most likely the VB is setup in such a way to provide more than apply pressure to the clutch packs under its operational range. This is my wifes daily driver, not our hot rod. I do not wish to make it shift harsher or later when unloaded.

I have the Mercedes training material on the NAG and looking at some things right now. In the end, to me the trans is not anything to really worry about.

FWIW...

Cory
Do you understand how a valve body works? A valve body directs hydraulic fluid to valves that allow the gears to shift. The valve body "pushes" fluid into the tranny itself. A better valve body will push more fluid so there is less stress to shift gears while towing your trailer. You dont need to use a very harsh shifting stage 3 one but just an upgraded one like a stage 2 at least.
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Old 09-17-2013, 10:32 PM
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Re: 2006 WK Towing Upgrades

Yes I do under stand how a valve body works...do you? Or are you a person who shops by what is a popular aftermarket component being marketed? I am not trying to be snotty, I was simply asking why you made a comment about trans fluid not making it to the valve body on time due to the external trans cooler which you didn't answer.

A valve body controls the application of fluid pressure by applying force to the clutch packs internal to the planetary gear sets within the transmission itself. The pump which is driven off the drive side of the torque converter is the motive force behind the transmission fluid and provides the overall system pressure and flow via an internal regulator. The valve body can be calibrated to deliver more fluid pressure to clutch packs upto the regulated pump pressure. It can also be altered to reduce shift time between application of clutch packs.

My comments on not wanting to alter the valve body is based on the premise of it not being needed for my intended application. The trans is designed to work with trailer loads upto 7200 lbs right from Daimler Chrysler and since the Jeep is not being used as a performance toy, money would be better spent on other improvements.

Either way it is a mute point now as I just traded our 3.7L on a 4.7L limited with the factory tow package this past weekend.

I appreciate all the feedback and conversation.

Cory
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Old 09-18-2013, 12:55 AM
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Re: 2006 WK Towing Upgrades

Quote:
Originally Posted by CumminsTrader View Post
Yes I do under stand how a valve body works...do you? Or are you a person who shops by what is a popular aftermarket component being marketed? I am not trying to be snotty, I was simply asking why you made a comment about trans fluid not making it to the valve body on time due to the external trans cooler which you didn't answer.

A valve body controls the application of fluid pressure by applying force to the clutch packs internal to the planetary gear sets within the transmission itself. The pump which is driven off the drive side of the torque converter is the motive force behind the transmission fluid and provides the overall system pressure and flow via an internal regulator. The valve body can be calibrated to deliver more fluid pressure to clutch packs upto the regulated pump pressure. It can also be altered to reduce shift time between application of clutch packs.

My comments on not wanting to alter the valve body is based on the premise of it not being needed for my intended application. The trans is designed to work with trailer loads upto 7200 lbs right from Daimler Chrysler and since the Jeep is not being used as a performance toy, money would be better spent on other improvements.

Either way it is a mute point now as I just traded our 3.7L on a 4.7L limited with the factory tow package this past weekend.

I appreciate all the feedback and conversation.

Cory
Ok, I think you may have misinterpreted my post. Your right there is no reason that fluid would have any problem reaching the trans cooler. What I was saying was that your cooled fluid should reach the clutch packs and the internals of the transmission, and a valve body would help with that. Anyways, congrats on your new truck! That was a very wise decision, as the 545rfe is a better tranny for towing hands down. I don't think you will regret it. Enjoy!
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