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2018 PW Leak behind Front Axle
Posted: Sun Oct 06, 2019 6:44 pm
by trailerpup
2018. 5k miles. Was under the truck installing the Dethloff skid plate (really nice product!) and noticed a leak. Does anyone have any information about this part. I'm a new convert from a Tundra and still learning the different systems on the RAM. Thanks.
Re: 2018 PW Leak behind Front Axle
Posted: Sun Oct 06, 2019 9:53 pm
by waldo
CAD. (Axle disconnect) I've never had one leak there. I don't think it's even supposed to have diff fluid in that section. Been a while, but I always thought it was dry.
Re: 2018 PW Leak behind Front Axle
Posted: Sun Oct 06, 2019 11:50 pm
by SeppW
CAD alright. Looks like the actuator housing seal or housing is leaking. Assume it's under warranty, take it to dealer and get it fixed.
Re: 2018 PW Leak behind Front Axle
Posted: Mon Oct 07, 2019 2:26 am
by cb1987
why didnt you determine what kind of fluid it was ? seems easy enough. diagnosing a leak is the same regardless of vehicle type
hard to tell from the photo. could be coolant or maybe engine oil from above. i dont believe theres supposed to be gear oil near the cad so if its gear oil you have a inner tube seal bad
Re: 2018 PW Leak behind Front Axle
Posted: Mon Oct 07, 2019 8:19 am
by waldo
cb1987 wrote: ↑Mon Oct 07, 2019 2:26 am
why didnt you determine what kind of fluid it was ? seems easy enough. diagnosing a leak is the same regardless of vehicle type
hard to tell from the photo. could be coolant or maybe engine oil from above. i dont believe theres supposed to be gear oil near the cad so if its gear oil you have a inner tube seal bad
The oil filter is right above that area. Recent oil change? I let the dealer do the 1st oil change on my '16. Drove it 300 miles to my cabin and found an oil spot in the gravel the next day when I moved the truck. Filter was loose, could spin it with two fingers and thumb.
Re: 2018 PW Leak behind Front Axle
Posted: Mon Oct 07, 2019 11:53 am
by DamageWagon
I’m glad you like your skid plate, thanks man!
If that smells like gear oil it would be a leaking axle seal inboard if the CAD collar.
The engine oil filter and the oil/coolant heat exchanger are above that area, check those as well.
Re: 2018 PW Leak behind Front Axle
Posted: Mon Oct 07, 2019 11:56 am
by Low_Sky
waldo wrote:CAD. (Axle disconnect) I've never had one leak there. I don't think it's even supposed to have diff fluid in that section. Been a while, but I always thought it was dry.
The axle seal is outboard of the CAD housing. This looks like gear oil to me.
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Re: 2018 PW Leak behind Front Axle
Posted: Mon Oct 07, 2019 12:02 pm
by Low_Sky
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Re: 2018 PW Leak behind Front Axle
Posted: Mon Oct 07, 2019 12:02 pm
by Low_Sky
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Re: 2018 PW Leak behind Front Axle
Posted: Mon Oct 07, 2019 12:04 pm
by TommyG
Check your transmission lines as well. I had a leak on that side that turned out to be ATF. It was weeping at the joint between the hard line and soft line.
Re: 2018 PW Leak behind Front Axle
Posted: Mon Oct 07, 2019 2:06 pm
by trailerpup
I noticed it late last night when I went back out to torque the Dethloff fasteners. Quick finger-it and sniff-it test excluded AF. I cleaned it up. Checked it this morning after drive to work with no leak. Whatever it is it is slow. I’ll do root-cause inspection and post up after work. Will not be going to the dealer unless absolutley neccessary. Thanks for all the good input!!
Re: 2018 PW Leak behind Front Axle
Posted: Mon Oct 07, 2019 2:09 pm
by DamageWagon
I’ve had axle seals leak and then seal back up with no good explanation. Possibly due to some deep water crossings we did. Been running the same deals for several years since then with no new leaks and several oil changes. I wouldn’t be surprised if it just went away. I’m not the only one that’s had this same experience.
Re: 2018 PW Leak behind Front Axle
Posted: Mon Oct 07, 2019 10:35 pm
by trailerpup
Light/slow weep from bottom of CAD housing to axle housing seal. Picture in original post is 5000+ miles. Research revealed it is wet behind the cover... earlier models look like an easy actuator housing gasket replacement. Late model part looks like the gasket is "built into" the $300 actuator. I'm going to monitor and maybe end up taking it in. Anyone do the by-pass? Hate going to the dealer. Usually, after the sale, they never see me again. Ever.
Re: 2018 PW Leak behind Front Axle
Posted: Tue Oct 08, 2019 1:41 am
by cb1987
i would of thought the seal was inboard of the cad but maybe not. while i do have a service manual, ive never needed to look at the front axle pages. ram couldnt be stupid enough to not have some kind of replacable paper or oring seal. then again, the dummies made the thermo housing with no replacable oring . so nothing suprises me any more
Re: 2018 PW Leak behind Front Axle
Posted: Tue Oct 08, 2019 10:32 am
by waldo
cb1987 wrote: ↑Tue Oct 08, 2019 1:41 am
i would of thought the seal was inboard of the cad but maybe not. while i do have a service manual, ive never needed to look at the front axle pages. ram couldnt be stupid enough to not have some kind of replacable paper or oring seal. then again, the dummies made the thermo housing with no replacable oring . so nothing suprises me any more
It used to be on the old trucks with the vacuum CAD. The front tubes were dry on those.
My 07 doesn't have a CAD and I have not had to pull an axle on the newer trucks.
AS for the bypass, I don't think anyone makes a one piece shaft for the new trucks. I checked back when I bought my 16 but have not looked since.
Re: 2018 PW Leak behind Front Axle
Posted: Tue Oct 08, 2019 4:59 pm
by cb1987
waldo wrote: ↑Tue Oct 08, 2019 10:32 am
cb1987 wrote: ↑Tue Oct 08, 2019 1:41 am
i would of thought the seal was inboard of the cad but maybe not. while i do have a service manual, ive never needed to look at the front axle pages. ram couldnt be stupid enough to not have some kind of replacable paper or oring seal. then again, the dummies made the thermo housing with no replacable oring . so nothing suprises me any more
It used to be on the old trucks with the vacuum CAD. The front tubes were dry on those.
the new trucks have a rubber gasket molded into the cad actuator housing ?
Re: 2018 PW Leak behind Front Axle
Posted: Tue Oct 08, 2019 6:05 pm
by trailerpup
Maybe replaceable O-ring. I haven't been able to find anything other than the complete unit. Might have to pop it off when I get a chance and see it up close...
Re: 2018 PW Leak behind Front Axle
Posted: Wed Oct 09, 2019 12:28 am
by cb1987
you would think there is a simple replaceable oring but that goes against any common sense. part diagrams dont show any oring that i could see. if its removable you might get it matched up at a hose and rubber shop
Re: 2018 PW Leak behind Front Axle
Posted: Fri Oct 11, 2019 9:41 pm
by RustyPW
waldo wrote: ↑Tue Oct 08, 2019 10:32 am
cb1987 wrote: ↑Tue Oct 08, 2019 1:41 am
i would of thought the seal was inboard of the cad but maybe not. while i do have a service manual, ive never needed to look at the front axle pages. ram couldnt be stupid enough to not have some kind of replacable paper or oring seal. then again, the dummies made the thermo housing with no replacable oring . so nothing suprises me any more
It used to be on the old trucks with the vacuum CAD. The front tubes were dry on those.
My 07 doesn't have a CAD and I have not had to pull an axle on the newer trucks.
AS for the bypass, I don't think anyone makes a one piece shaft for the new trucks. I checked back when I bought my 16 but have not looked since.
RCV axles. Pricey. Never have to worry about breaking one.
https://www.rcvperformance.com/ultimate ... nnect.html
Re: 2018 PW Leak behind Front Axle
Posted: Sun Oct 13, 2019 10:01 am
by waldo
RustyPW wrote: ↑Fri Oct 11, 2019 9:41 pm
waldo wrote: ↑Tue Oct 08, 2019 10:32 am
cb1987 wrote: ↑Tue Oct 08, 2019 1:41 am
i would of thought the seal was inboard of the cad but maybe not. while i do have a service manual, ive never needed to look at the front axle pages. ram couldnt be stupid enough to not have some kind of replacable paper or oring seal. then again, the dummies made the thermo housing with no replacable oring . so nothing suprises me any more
It used to be on the old trucks with the vacuum CAD. The front tubes were dry on those.
My 07 doesn't have a CAD and I have not had to pull an axle on the newer trucks.
AS for the bypass, I don't think anyone makes a one piece shaft for the new trucks. I checked back when I bought my 16 but have not looked since.
RCV axles. Pricey. Never have to worry about breaking one.
https://www.rcvperformance.com/ultimate ... nnect.html
I was thinking more on the Yukons that they made for the old trucks.
I don't quite hate my CAD enough to spend $2500.

Re: 2018 PW Leak behind Front Axle
Posted: Tue Oct 15, 2019 3:22 pm
by olyelr
trailerpup wrote: ↑Sun Oct 06, 2019 6:44 pm
2018. 5k miles. Was under the truck installing the Dethloff skid plate (really nice product!) and noticed a leak. Does anyone have any information about this part. I'm a new convert from a Tundra and still learning the different systems on the RAM. Thanks.
Lets us know the outcome of this.
I spot some thuren boogies up there

Re: 2018 PW Leak behind Front Axle
Posted: Tue Oct 15, 2019 7:34 pm
by DamageWagon
One of the Moab attendees last year blew his front axle. When he got a new one in he did free spins and had a 13 shaft turned down to fit the axle seal. He now has a non-CAD axle. The free spins aren’t necessary, so you can save a lot of money with just a machined axleshaft. The free spins allow you to have 2-Low
Re: 2018 PW Leak behind Front Axle
Posted: Tue Oct 15, 2019 9:15 pm
by olyelr
DamageWagon wrote: ↑Tue Oct 15, 2019 7:34 pm
One of the Moab attendees last year blew his front axle. When he got a new one in he did free spins and had a 13 shaft turned down to fit the axle seal. He now has a non-CAD axle. The free spins aren’t necessary, so you can save a lot of money with just a machined axleshaft. The free spins allow you to have 2-Low
You can do the 2-lo kit electronically pretty cheap with the new trucks. That is, if you keep the cad.
Re: 2018 PW Leak behind Front Axle
Posted: Tue Oct 15, 2019 9:15 pm
by DamageWagon
olyelr wrote:DamageWagon wrote: ↑Tue Oct 15, 2019 7:34 pm
One of the Moab attendees last year blew his front axle. When he got a new one in he did free spins and had a 13 shaft turned down to fit the axle seal. He now has a non-CAD axle. The free spins aren’t necessary, so you can save a lot of money with just a machined axleshaft. The free spins allow you to have 2-Low
You can do the 2-lo kit electronically pretty cheap with the new trucks.
Not if you replace the CAD axleshaft with a single piece unit...
Re: 2018 PW Leak behind Front Axle
Posted: Tue Oct 15, 2019 9:18 pm
by olyelr
DamageWagon wrote: ↑Tue Oct 15, 2019 9:15 pm
olyelr wrote:DamageWagon wrote: ↑Tue Oct 15, 2019 7:34 pm
One of the Moab attendees last year blew his front axle. When he got a new one in he did free spins and had a 13 shaft turned down to fit the axle seal. He now has a non-CAD axle. The free spins aren’t necessary, so you can save a lot of money with just a machined axleshaft. The free spins allow you to have 2-Low
You can do the 2-lo kit electronically pretty cheap with the new trucks.
Not if you replace the CAD axleshaft with a single piece unit...
Lol i just edited my post for that