Seals around the axles - where best to buy?

[Schmirgel]

Hello everyone,

We want to install 2 new differentials soon - and replace a few seals at the same time.
Unfortunately, we are a little unsure where to buy which gasket is best and cheapest, as there are huge price differences.

Do you have any tips? Colored one are same seals - only a mark for me

 

[Keith Knight]

I’m at a similar position, I completely rebuilt the hubs last winter and now have to replace front axle housing outer seals. So this time when I have it apart I’m considering the front axle sleeve bushings, axle U- joints, pinion seal….

 

[GeneralDisorder]

Most of this stuff is Viton or silicone from the factory and should last a very long time in service. Barring some kind of fluid contamination, etc. The exception being the CTIS seals which are exposed to potential contamination from the wet tank (fed directly from it). This manifests as gear oil from the hub being present at the CTIS banjo bolt threads on the supply lug stud.

If you are changing entire differentials - first off what is the goal? Are you aware of ECO hubs? If you are considering going from 3.90 to 3.07 you should seriously consider the ECO hubs instead.

 

[Schmirgel]

Most of this stuff is Viton or silicone from the factory and should last a very long time in service. Barring some kind of fluid contamination, etc. The exception being the CTIS seals which are exposed to potential contamination from the wet tank (fed directly from it). This manifests as gear oil from the hub being present at the CTIS banjo bolt threads on the supply lug stud.

If you are changing entire differentials - first off what is the goal? Are you aware of ECO hubs? If you are considering going from 3.90 to 3.07 you should seriously consider the ECO hubs instead.

Thank you for your message. We would simply like to change the seals as a preventative measure - if we are already working on them anyway. Unfortunately, I couldn't find out from your message where to order them

We have looked at ECO Hubs - but are not really convinced. Why would that be better than replacing the diffs? Apart from saving time? Am I simply leaving out components?

 

[Schmirgel]

I’m at a similar position, I completely rebuilt the hubs last winter and now have to replace front axle housing outer seals. So this time when I have it apart I’m considering the front axle sleeve bushings, axle U- joints, pinion seal….

Did you get any feedback on the best place to get the seals without them being overpriced?

 

[MatthewWBailey]

We have looked at ECO Hubs - but are not really convinced. Why would that be better than replacing the diffs? Apart from saving time? Am I simply leaving out components?

View attachment 927272

I had 3.07s installed by the original shop (bad choice), Not much benefit in driveline speed reduction with 3.07s, which is a big factor in these trucks. However, The ECO hubs Half the driveline speed, putting the engine into the peak torque band for all gears/speeds allowable on US highways (80 across Utah). I'm reinstalling the old 3.90 diffs back in there (with Detroit lockers) now that I have ECO. If you already have 3.90s it's short sighted IMO to not goto ECO unless you're only off roading. The heat and noise reduction is significant. As @GeneralDisorder has stated many times, the extension of life by halving the driveline speed and reducing engine rpm to only peak rpm range is huge. For example, My driveshaft u-joints are shot with only 14k miles with the original gearing. That's 4 items at $125 each. IMO, as a non professional mechanic, running a 6 cylinder diesel at max 2400 rpm sustained, just to do 60-65mph on highway driving is a special category of obtuse. (And 3.07s only give you 71mph at max rpm)

 

[GeneralDisorder]

We have looked at ECO Hubs - but are not really convinced. Why would that be better than replacing the diffs? Apart from saving time? Am I simply leaving out components?

Have you read the thread on them?

When you say you are "not really convinced" - convinced of what exactly?

What questions and concerns do you still have after reading the entire thread?

FWIW - In my opinion 3.07's and 3.90's with the factory reductions are a waste of time unless you are running a quarry truck or something that NEVER sees over 40 mph (65 kph).

You will destroy the drivetrain 5x to 10x faster with the 2:1 final drives. The military's expected lifespan of these truck is 35,000 miles. And the drivelines still had problems even with that low expectation.

 

[GeneralDisorder]

Did you get any feedback on the best place to get the seals without them being overpriced?

Define "overpriced"?

Big rigs are not cheap to run. Specialized Army big rigs are even more expensive to run. Lots of parts not shared by over the road trucks. Any Meritor/Rockwell/Axle-Tech dealer can order the parts. Being you are in Germany it's difficult to recommend anything that is US based since I don't know if they ship internationally. Many parts for these trucks have export controls also and the manufacturers won't ship them outside the US. Neihoff for example - the charging system manufacturer - requires an EUC to sell military part numbers to the civilian market.

And there is a LOT of parts for which they are effectively NO sources outside the military. For those your only hope is used or surplus which is all in the US.

 

[Schmirgel]

Have you read the thread on them?

When you say you are "not really convinced" - convinced of what exactly?

What questions and concerns do you still have after reading the entire thread?

FWIW - In my opinion 3.07's and 3.90's with the factory reductions are a waste of time unless you are running a quarry truck or something that NEVER sees over 40 mph (65 kph).

You will destroy the drivetrain 5x to 10x faster with the 2:1 final drives. The military's expected lifespan of these truck is 35,000 miles. And the drivelines still had problems even with that low expectation.

In Germany / Europe we have a maximum speed limit of 50 mph - so changing the maximum speed to 80mph does not bring the success that it does in the USA.
In addition, all modifications to the vehicle must be approved by TÜV. If you change a diff now, this is inconspicuous/not visible. When changing to ECO hubs, questions will arise that are difficult or impossible to answer. Or are there official approvals from the truck manufacturers for the ECO hubs?

As we have already bought the 3.07s, we will now install them. The aim, as I said, is to reduce the revs at 50mpg and still be prepared for rough terrain in Africa (that's where we're heading). In Africa, even 50mph will be very rare - the speed in Europe applies to highways. A maximum speed of 38mph is allowed off these highways. This is where we will be driving most of the time.

Of course we are keeping the ECO hubs in mind - but we are already on the way to 3.07s. Thank you for all the information you share with us.

 

[Schmirgel]

Define "overpriced"?

Big rigs are not cheap to run. Specialized Army big rigs are even more expensive to run. Lots of parts not shared by over the road trucks. Any Meritor/Rockwell/Axle-Tech dealer can order the parts. Being you are in Germany it's difficult to recommend anything that is US based since I don't know if they ship internationally. Many parts for these trucks have export controls also and the manufacturers won't ship them outside the US. Neihoff for example - the charging system manufacturer - requires an EUC to sell military part numbers to the civilian market.

And there is a LOT of parts for which they are effectively NO sources outside the military. For those your only hope is used or surplus which is all in the US.

Thank you for your feedback. We are primarily concerned with the large price differences - and how these can be avoided. As an example, here is a comparison of the diff seals:

National Seals 100263 Multi-Purpose Seal + Cross Reference | FinditParts

National Seals 100263 Multi-Purpose Seal ✓ Order now for same-day shipping on eligible purchases from FinditParts.com, America's online marketplace for heavy duty parts.

www.finditparts.com

Front or Rear Differential Pinion Seal

Shop at Midwest Military Equipment for the Front & Rear Differential Pinion Seal, a high-quality replacement with multiple part alternatives. One-piece design for added reliability.

midwestmilitaryequipment.com

Thats a big difference between the "same" seal?!

 

[Keith Knight]

Did you get any feedback on the best place to get the seals without them being overpriced?

No and I haven’t had time to dig into it yet.

 

[GeneralDisorder]

In Germany / Europe we have a maximum speed limit of 50 mph - so changing the maximum speed to 80mph does not bring the success that it does in the USA.

It's not so much a matter of speed. You will realize much better fuel economy if you stick to 50 mph. My fuel economy test showed an improvement of 3 mpg at 55 mph with ECO hubs over the original 3.90 differentials.

In addition, all modifications to the vehicle must be approved by TÜV. If you change a diff now, this is inconspicuous/not visible. When changing to ECO hubs, questions will arise that are difficult or impossible to answer. Or are there official approvals from the truck manufacturers for the ECO hubs?

I'm sure Mike could make you a set without the name on them and I suspect that no one would notice or have any idea that you have changed the final drive. These types of modifications aren't considered in the US. There's no one looking at or caring about what final drive a private owner has in their truck. In the US that would be ridiculous besides being unenforceable. There's basically no one in the US vehicle licensing ecosystem that would even know what a hub reduction planetary IS let alone whether or not your imported European truck would or would not be equipped with them. I doubt there's anyone at TÜV that knows either. Don't volunteer any information and if you get questions - proclaim ignorance, promise answers, and find another inspector.

As we have already bought the 3.07s, we will now install them. The aim, as I said, is to reduce the revs at 50mpg and still be prepared for rough terrain in Africa (that's where we're heading). In Africa, even 50mph will be very rare - the speed in Europe applies to highways. A maximum speed of 38mph is allowed off these highways. This is where we will be driving most of the time.

Of course we are keeping the ECO hubs in mind - but we are already on the way to 3.07s. Thank you for all the information you share with us.

Even with the reduction from 7.80 to 6.14 your driveline speeds will still be quite high. Concerningly high for the u-joints, and the C6 thrust bearing in the transfer case. Everything in the truck is happier, quieter, and cooler with the ECO hubs. Again - please read through the entire ECO hub thread.

 

[Keith Knight]

After a total of 12 months and 23,000 miles with 3.07 gears, average speed of 50-60 mph, never faster than 60 no matter terrain or road I get a consistent 6.5 mpg.

 

[Schmirgel]

It's not so much a matter of speed. You will realize much better fuel economy if you stick to 50 mph. My fuel economy test showed an improvement of 3 mpg at 55 mph with ECO hubs over the originaly 3.90 differentials.



I'm sure Mike could make you a set without the name on them and I suspect that no one would notice or have any idea that you have changed the final drive. These types of modifications aren't considered in the US. There's no one looking at or caring about what final drive a private owner has in their truck. In the US that would be ridiculous besides being unenforceable. There's basically no one in the US vehicle licensing ecosystem that would even know what a hub reduction planetary IS let alone whether or not your imported European truck would or would not be equipped with them. I doubt there's anyone at TÜV that knows either. Don't volunteer any information and if you get questions - proclaim ignorance, promise answers, and find another inspector.



Even with the reduction from 7.80 to 6.14 your driveline speeds will still be quite high. Concerningly high for the u-joints, and the C6 thrust bearing in the transfer case. Everything in the truck is happier, quieter, and cooler with the ECO hubs. Again - please read through the entire ECO hub thread.

OK, I´ll read the entire thread and we can talk to each other after

 

[GeneralDisorder]

After a total of 12 months and 23,000 miles with 3.07 gears, average speed of 50-60 mph, never faster than 60 no matter terrain or road I get a consistent 6.5 mpg.

And with the ECO hubs and 3.90's you would get close to 10 mpg. That's a LOT of money over time. They pay for themselves.

You would have saved 1200 gallons of fuel. At todays rates you would be ~$4,000 richer right now. Not to mention lighter not having consumed dozens of gas station burritos while you pump it up.

 

[Keith Knight]

I changed gears almost 7 years ago. Way before eco hubs. If I had a choice today I would probably go eco hubs but I don’t have my old gears to reverse it and install eco hubs.

 

[Ronmar]

Yea the driveshaft RPM at our angles is way past the red line at highway speed. Operating an engine past its peak torque RPM is like driving with an exhaust brake engaged due to the increased pumping losses, which is why users are noting significant increases in mileage with the hubs installed. 3.07 gears help, they are just not a big enough step in the right direction… removing the 2:1 at the hub actually brings the driveshaft RPM back onto the driveshaft angle/Max RPM chart…

 

[GeneralDisorder]

I changed gears almost 7 years ago. Way before eco hubs. If I had a choice today I would probably go eco hubs but I don’t have my old gears to reverse it and install eco hubs.

Well - there are plenty of parts trucks out there and more arriving in the market every day. LOTS of these trucks still going through DLA. Many of them now with the 4x4 high-pinion rear axle which would be a better choice all around even if you stick with the 3.07's because it addresses at least one of the design flaws and allows the u-joints to run inside their design envelope and thus dramatically increase their lifespan.

It sucks that you basically have to redo the whole enchilada but for +3 mpg and potentially avoiding a catastrophic u-joint failure...... There's a Facebook group member that essentially totaled his truck recently with a u-joint failure. The failure decimated his under-carriage, broke the transmission behind the bell-housing, and cracked the engine block. Being an A0 truck...... the recommendation from most of us is to find another (newer hopefully) truck and swap his 1079 box onto it. Easier than replacing engine and transmission and rear axle and everything else it shattered and mutilated. Real F'ing mess he's got on his hands.

 

[Keith Knight]

That’s crazy. How do you recognize the high pinion. And wouldn’t you want that front and rear.

 

[Keith Knight]

This is my rear. Front looks the same.