Too Many Rear NV4500 SEALS

[Greenlee]

I'm leaning more and more to keeping the 99, Added up close to $6,000 in new parts. One thing that I don't understand is in March of this year another rear seal was put in and it is also leaking. It's not a big leak but a little drip periodically. Where should I start looking and how do I verify an issue is causing this? Center Bearing seems to be fine. There is no way I can jack this truck up to get under it but I have a friend who has a shop that will put it on a rack for inspection. Should I try and find a diesel shop that deals with diesel repairs to take a look. So far the Dodge Dealership, a second automotive repair shop and a third repair shop that just put on new shocks, upper and lower ball joints, and a new radiator also put in a new seal. I saw an article that said get away from the OEM and use Felpro but some have said that it doesn't matter, Felpro leaks as well. I don't know if the yoke has been checked for any egg shape or bad spots but you would think who ever put the seal in would look at that. It's not enough to put another in since according to the receipts $550 has been spent for parts and labor. All during a 50,000 mile period. Any ideas???????

[Dieselfuture]

Mine is kind of doing the same thing only mine is four wheel drive so I have a leak on tcase output shaft, same small drip. Mine started after I had driveshaft rebalanced, but I had it rebalanced again just to be sure and nothing changed. 

Check your vent make sure it's not plugged,  and if you overfill it too much, that may do it also. 

Maybe a bushing in there you could change.

[Haggar]

Greenlee,

 

I would say it is the output bearing is beginning to fail, or the yoke is not round/correct size anymore.  You may be able to correct both.  The schematic seems to show that the rear support is pretty easily replaced.  I am not seeing a bearing in the schematic from

the FSM.   It appears the 2wd rear housing comes off easily and you could look at the problem.  The manual also notes a rubber spline seal.  this would keep the fluid from creeping through the splines in the yoke.  (possibly the 2wd tailshaft extension housing has a bushing ala the TC tailshaft?

 

 

 

DF,

The tailshaft on the 4wd has a bushing in it.  As that bushing wears it will not control the yoke properly and the seal will be damaged.

This is a picture I had when I needed to get a new tail shaft. (there were two different casting numbers but both worked ok) 

 

HTH

 

Hag

[Dieselfuture]

@Haggar thank you,  funny thing is I have a bushing and a new seal sitting waiting on me for few years now, but when I had driveshaft off last time, I slipped new bushing over the yolk and it wasn't any tighter than the one that's in the tail shaft or so it seemed. So I'm thinking maybe my yoke is bad but with only 160k on it hard to believe it wore out and other people with 400k +  don't have an issue yet. But then again I don't Know full history of this truck either. 

[Haggar]

hmmm,

 

I wonder if I remember an earlier discussion.....(the mind is a terrible thing to lose... if you see mine, let me know please...)    I do remember trying to find what the ACTUAL installed diameter range of the bushing should be, and what the yoke ACTUAL dimensional tolerances are so I could calculate the actual bushing clearance....   but alas those are hard numbers to find. 

 

Do keep in mind, the bushing is a press fit.  So if your clearance uninstalled is the same as what you have, it will be tighter when the new one is installed.   It also may be worth a check that the tail shaft is not upside down.  There is a drain hole that should be on the bottom, draining the area between the bushing and the seal.  

 

Hope you figure it out DF!

 

Hag

[Guest 04Mach1]

I would look at the yoke that goes through the seal. It's fairly common for seals to wear grooves in things like axles, crankshafts, input shafts, and yokes causing a loose fit inside the seal. It's so common that wear sleeves are available for many of these type of parts. Loose bushings and bearings will cause frequent oil seal failures also.

[sooxies]

14 hours ago, Dieselfuture said:

Mine is kind of doing the same thing only mine is four wheel drive so I have a leak on tcase output shaft, same small drip. Mine started after I had driveshaft rebalanced, but I had it rebalanced again just to be sure and nothing changed. 

Check your vent make sure it's not plugged,  and if you overfill it too much, that may do it also. 

Maybe a bushing in there you could change.

I have the same darn problem.  Just annoying.  Slip yoke and/or bushing in the output shaft I'm betting on.  Vent checked out fine. 

[Mopar1973Man]

Thanks for mention of the vent. Lot of people forget the vent.

[Greenlee]

On ‎9‎/‎26‎/‎2018 at 7:05 AM, Dieselfuture said:

Mine is kind of doing the same thing only mine is four wheel drive so I have a leak on tcase output shaft, same small drip. Mine started after I had driveshaft rebalanced, but I had it rebalanced again just to be sure and nothing changed. 

Check your vent make sure it's not plugged,  and if you overfill it too much, that may do it also. 

Maybe a bushing in there you could change.

I'll check the vent, I know the fluid level is good, right on the mark. I will be able to tell more once it's in the air and that will be in a couple of weeks. Thanks

On ‎9‎/‎26‎/‎2018 at 7:26 AM, Haggar said:

Greenlee,

 

I would say it is the output bearing is beginning to fail, or the yoke is not round/correct size anymore.  You may be able to correct both.  The schematic seems to show that the rear support is pretty easily replaced.  I am not seeing a bearing in the schematic from

the FSM.   It appears the 2wd rear housing comes off easily and you could look at the problem.  The manual also notes a rubber spline seal.  this would keep the fluid from creeping through the splines in the yoke.  (possibly the 2wd tailshaft extension housing has a bushing ala the TC tailshaft?

 

 

 

DF,

The tailshaft on the 4wd has a bushing in it.  As that bushing wears it will not control the yoke properly and the seal will be damaged.

This is a picture I had when I needed to get a new tail shaft. (there were two different casting numbers but both worked ok) 

 

HTH

 

Hag

Thanks for the details and pictures, I hope it is something simple. If I can't see anything unusual I'm going to find some body that deals with the NV5400. The leak is very small. If it were me driving it I would have never replaced 2 more times until I got a chance to look at it and research on the Forum. Thanks

On ‎9‎/‎26‎/‎2018 at 7:46 AM, Dieselfuture said:

@Haggar thank you,  funny thing is I have a bushing and a new seal sitting waiting on me for few years now, but when I had driveshaft off last time, I slipped new bushing over the yolk and it wasn't any tighter than the one that's in the tail shaft or so it seemed. So I'm thinking maybe my yoke is bad but with only 160k on it hard to believe it wore out and other people with 400k +  don't have an issue yet. But then again I don't Know full history of this truck either. 

     It's good to know that there is one Dodge out there that is not leaking. Apparently it's not uncommon to have a small drip. There has to be a reason why because it should not leak at all even with a little wear. When it get bad I should be able to put a finger on the problem. Thanks for the comment

On ‎9‎/‎26‎/‎2018 at 9:09 AM, Haggar said:

hmmm,

 

I wonder if I remember an earlier discussion.....(the mind is a terrible thing to lose... if you see mine, let me know please...)    I do remember trying to find what the ACTUAL installed diameter range of the bushing should be, and what the yoke ACTUAL dimensional tolerances are so I could calculate the actual bushing clearance....   but alas those are hard numbers to find. 

 

Do keep in mind, the bushing is a press fit.  So if your clearance uninstalled is the same as what you have, it will be tighter when the new one is installed.   It also may be worth a check that the tail shaft is not upside down.  There is a drain hole that should be on the bottom, draining the area between the bushing and the seal.  

 

Hope you figure it out DF!

 

Hag

My mind went AWOL a long time ago, not kidding. Hope you find yours. I saw some dimensions way back when researching the issue of the 5th gear nut coming off. Doesn't seem to be an answer for that so I try not to worry about it. You are right though, having the numbers to go by and check tolerances would be good to know and helpful. I'll look at the drain hole when I get it on the rack. YouTube should have some videos that are detailed showing the steps for putting a new seal in, I should look to see, it could help me understand all the steps involved. Thank you for the comment and advice 

 

On ‎9‎/‎26‎/‎2018 at 8:55 PM, 04Mach1 said:

I would look at the yoke that goes through the seal. It's fairly common for seals to wear grooves in things like axles, crankshafts, input shafts, and yokes causing a loose fit inside the seal. It's so common that wear sleeves are available for many of these type of parts. Loose bushings and bearings will cause frequent oil seal failures also.

I'll do that and I'm thinking the same thing that there should be some evidence of wear or grooves like you are saying. Depending on what I am looking at and how much time I have with the truck in the air good advice all the way around.

 

On ‎9‎/‎26‎/‎2018 at 9:16 PM, sooxies said:

I have the same darn problem.  Just annoying.  Slip yoke and/or bushing in the output shaft I'm betting on.  Vent checked out fine. 

Glad I'm not alone and yes it is annoying but the answer is out there just like the X Files. One day we will know.....maybe not. That was a good tip on the vent, didn't consider it but I don't get to work on these kind of projects any more. Hopefully I will find an answer to share.