NP241 DHD tailshaft bushing part number

[KATOOM]

Does anyone know the part number for the NP241 DHD tailshaft bushing?  I've been to the parts stores and the dealer but neither could help.  I've seen a few versions online but I'm hoping to have the correct part delivered the first time.

 

The reason I'm doing this is because I've replaced the seal three times.  The last time I researched and researched and determined the correct one since all have slightly different shaft size ID which is weird but nonetheless...  So after installing the seal I thought was best the leak was gone for a long time.  Then...as usual, I took the 5th wheel out for a camping trip and once again the tailshaft started puking like a stuck pig, spewing fluid spray all over the underside of the truck.

 

I measured the slip yoke play and its very minimal, but must be enough to allow deflection of the seal under power with 14k behind me.

Thanks guys...

[Stanley]

Are you just talking about the rear seal where the yoke goes into the t-case? 

I can get the whole set up here for like 20$. I use these guys all the time, awesome people too! 

Edited July 6, 2019 by Stanley

[Me78569]

Have you looked at the dhd r&r article i did?  I thought there were part numbers in there.

[KATOOM]

No, not the output shaft seal.  I'm looking for the brass (or ? material) sleeve bushing located inside the rear portion of the tailshaft housing extension.  It should have rifling groves and be about 2" long and what the slip yoke rides on.

I've seen diagrams which identify it for the 231 but strangely there's no recognized part on a diagram for the 241.  And yes, I looked through the R&R article but unless I overlooked it, there was nothing about that bushing.

 

With the rear seal obviously not wanting to seal over time, replacing this bushing is my last option fixing this problem.

Edited July 6, 2019 by KATOOM

[Towrigdually]

If I remember correctly, I called the guys at quad4x4.com out of Montana and they had the bushing. Needed it when I rebuilt the t-case in my truck.

[Russ Roth]

If you are near a Six states they usually are very good about this type of thing.   Here they sometimes know the part # right off the top of their head and usually in stock.  At least that's how it happened with my '67 W200.  I would think this would be easier.

[NIsaacs]

This looks like it will fit:

 

https://torqueking.com/product/90025/qu90025-rear-output-bushing-heavy-duty-241-261-263-transfer-cases/

 

https://torqueking.com/product/10586/tk10586-dodge-np241-transfer-case-rear-housing-shim-gasket/

[NIsaacs]

Where are you getting your seals? I wonder if aftermarket is not quite right. I have replaced several also.

 

This is the current offering from NP/NV.

 

https://torqueking.com/product/10896/qu10896-np241dhd-rear-output-seal-1996-2002-dodge-transfer-cases/ 

 

It supersedes this one.

 

https://torqueking.com/product/50171/qu50171-rear-o-p-shaft-seal/

[BBHD]

@KATOOM I have been getting ready for this bushing replacement myself. I have been looking at the same bushing @NIsaacs listed. 

[Dieselfuture]

Would love to know the outcome, I've been debating if I want to change that bushing for few years now. Mine is just a drip though. I got my bushing from local tranny guy, it was just wrapped in paper no box, he probably gets them in a case or something. No part number, what's posted above seems to be the right one. I suppose you checked the vent and it's not over filled. 

[BBHD]

2 hours ago, Dieselfuture said:

 I've been debating if I want to change that bushing for few years now. Mine is just a drip though.

You're not the only one 

[KATOOM]

As much as I dont want to have to change the bushing, I'm also questioning if this will even fix the problem.  Here me out...

 

As I stated before, I changed the seal and it was leak free.  This has generally been the case except when I used a cheaper seal which I know was too loose of an ID surface.  That one leaked right away.

 

Any leaking always takes place during towing conditions and continues to do so until I replace the seal.  I've checked the clearance of the slip yoke movement and its very minimal.  I'll upload a video when I get to a better internet connection so you can see what I mean.

 

Knowing that a short bed truck will have more driveshaft movement due to the angle of the shaft, I'm wondering if the yoke is being shoved too far into the seal while towing and damaging it when there's weight on the truck.

[Dieselfuture]

24 minutes ago, KATOOM said:

I'm wondering if the yoke is being shoved too far into the seal while towing and damaging it when there's weight on the truck.

Not a bad guess, may have to polish up that unused surface 

[KATOOM]

Here's a short video I took of the tailshaft bushing movement.  I'm not claiming to be right but I've handled more than a few tailshafts checking for excess play and this one seems to be in great shape.  You can see that the slight amount of movement doesnt even cause the boot to move.

Tell me what you think...

 

 

[Dieselfuture]

2 hours ago, KATOOM said:

 Tell me what you think... 

Gremlins, looks just fine. Mine is same that's why I haven't changed anything yet. I've sliped new bushing over yoke when I had drive shaft out to re balance, because I thought maybe it was out of balance causing the leak. Btw my leak started after I removed drive shaft to do rear pinion seal, I did not change transfer case seal at that time, it was not leaking then. About a week later after the rear pinion seal and new u joints and driveshaft rebalance it started to drip. So I changed the seal in tcase, still dripped. Then I went and bought a bushing and another seal at the same time I took the driveshaft back to have it rebalanced just to be sure, it was with in spec but the guy took weights off and rebalanced it anyway. Still dripping today. That's my story.

 

The only other thing I can think off, is when you slide drive shaft in, the lip of the seal may roll inwords we can't see it because of the protection boot. I had same thing happen on my Honda after changing timing belt I also changed all the seals, within a week I was dripping oil, took it all apart and started looking, at first glance looked fine because you can't really see oil seal behind dust seal. After I took it out it was obvious the lip rolled outward when I pushed it over crankshaft. So what I did is used pvc pipe same size 1/12 I believe, put seal on pvc then held it against crankshaft and slid it on, it had no way of rolling wrong. 

OK I'm done for now. 

Edited July 7, 2019 by Dieselfuture
Dumb phone

[KATOOM]

If it didnt entail a lot of effort and money, I'd love to convert the TC tailshaft to a fixed yoke with a slip joint driveshaft.  I've never been a fan of these slip yoke tailshafts.

[Haggar]

Katoom,

 

One thought is could your TC vent be pinched or plugged?   (it should be on the firewall near the vacuum lines that go to the TC for the CAD to operate)   

 

Another thought,  I need to do some more research, but some cross sections of radial seals (seal designs) are limited to very small shaft to bore mis-alignment ( as low as 0.005")  and total dynamic runouts of as little as 0.003"    I agree  New Ventures engineers should not have used a design that needed to be that precise, but.....

 

If it is not the vent, and the surface of the yoke is good and not damaging the seal, and you are not dragging foreign materials into the seal to damage it, it has to be "runout" killing it.  I agree at any instant in time, it is not run-out, but loaded vs unloaded is forcing it to operate in different locations, so your shaft to bore misalignment is a constantly changing number, based on ride height and load being applied.  (this means while pulling the camper up the hill it operates in one position, coming down the hill it is operating in a totally different position. 

 

I truely believe that if you have ruled out the other items, it has to be the inability of the bushing to hold the yoke centered. 

 

HTH
 

Hag

[KATOOM]

Haggar, thank you for the detailed response...

 

Yes the vent is clear and has always been as I've checked it before thinking it could be the culprit.  The runout as you described it makes perfect sense, and would be sad if thats how intolerant NP was with their design specs.

 

Let me throw this in the mix of my problem though...  Instead of doing anything right away, I washed the underside of the truck and took it for a 20 mile drive yesterday.  Strangely the seal is NOT leaking.  This tells me that:

1) I didnt drive far enough, but I cant imagine since it was leaking enough to leave spray droplets all over under the truck while towing.  Or 2) the fluid level is too low to push fluid up against the seal (cant imagine since its almost perfectly full). Or 3) there's something going on associated with towing and either the weight of the trailer changing the driveline position or the amount of load the driveline is placed under while towing that heavy.  Also noting that the driveline runs very smooth and has been balanced.

 

I've checked the driveshaft wear patterns and it doesnt seem that the rougher portion of the shaft is making it that far into the boot.  Also, to help reduce rough corrosion from collecting, I grease the back portion of the slip yoke.  Not sure how much it helps though.

Edited July 9, 2019 by KATOOM

[Haggar]

Katoom,

 

Dang it.  I was hoping vent really.  That would be easily explained with operating temps unloaded vs loaded.  so nix that one.

 

The NVs usually have a pump in the TC that spray oil to the tail shaft bushing.  (I only know this from the GM NV t/c's but I assume (and they refer to it in our FSM) they have the same on ours.)  So only if you are really low on fluid, would there not be oil circulating to the tailshaft bushing. 

 

So I think that circles us back to loading (or torque application) changing the position of the yoke in the tail housing. 

 

Since you are a short bed, are you running a 1 piece or 2 piece drive shaft?

 

GL

 

Hag

[NIsaacs]

During seal install, are you getting the weep hole in the down position?

 

https://torqueking.com/product/50171/qu50171-booted-rear-output-seal-for-98-02-np241dhd-transfer-cases/#note1