Rear axle leak

[Grimm21]

I need some help from the veteran fix it guys here on S S. I have found a small leak on top of my rear axel in what I think is the back of the through shaft on my m923. I have looked through the TM and I am hoping is a simple gasket and seal. I have a nsn number for the gasket 5330004195872 I have not been able to locate this gasket yet. There is also a seal plain encased I do not have the nsn number for this but have located this part so the million dollar question is. is this leak as simple as just replacing one or both of these parts or is it something deeper I am not a mechanic but do have a working knowledge of how things go and I know these monsters can get complicated. Thanks

 

[porkysplace]

You might want to post some pictures .

 

[Grimm21]

You might want to post some pictures .

I was waiting for this so I will try and post a couple pictures

 

[Grimm21]

I hope these help

 

[Scar59]

Looks like a normal axle seep/sweat. Leaks leave fluid on the concrete. Concrete is way to clean. Truck may need to be driven to get the seals wet. There are a lot of axles in my fleet, your axle is a lot cleaner than mine.

 

[Grimm21]

Thank you scar59 for the info I was hoping for this answer but I always expect the worst but pray for good news. I have been running the truck the past couple days and just started to notice it was weeping and running down the axel so I figure to ask the people I know will know just what is going on with the green monster. Just to let every one know this is my first truck and is a real learning experience.

 

[porkysplace]

Easy seal to replace .
this is the seal you will need.
http://ccsurplus.com/content/oil-se...on-transfer-case-differential-500177-m800-m54

 

[Tow4]

Replacing the pinion seal is not that hard. I got my seals from bigmikem35a2 on Ebay for $15.95 each. I would buy a couple because if one is bad the others are probably not far behind. I have replaced 2 on my M818.

Read the TM first. I suggest using a 3/4 inch impact to remove and re-install the pinion nut. Use PB Blaster or WD40 if you have a hard time getting the pinion nut off.

The process is as follows:

Remove drive shaft if the flange the seal is leaking at is driven. Make a reference mark on the pinion flange and drive shaft flange so they get back together the same way.

Remove the cotter pin from the pinion nut. You need to be able to tighten the nut back to the same torque so make reference marks on all parts. Take a magic marker and draw a line across the pinion to show where the cotter pin is. Mark the pinion nut on the ears on each side where the cotter pin was on the nut, also mark the pinion flange.

Remove the pinion flange nut. The pinion flange should now just pull off. Check the pinion flange seal surface and make sure it is smooth. One of mine had some scratches that I had to sand out with some 1000 grit paper and buffing compound. If there is a lot of scoring you can have a new sleeve installed on the flange.

Remove the cover that has the seal and remove the seal. Clean the mating surfaces where the seal goes and where the cover mounts to the differential. Clean the mounting surface on the differential.

Put a bead of RTV where the seal goes and install the new seal. Check to make sure RTV has not gotten on the front of the seal; wipe it off if necessary. Apply a bead of RTV around the cover mounting holes. Re-install the cover on the differential.

Put a little grease on the seal lips and noting your alignment marks re-install the pinion flange. Re-install the nut and torque it down until the marks line up with the marks on the pinion. Re-install the cotter pin. Re-install the drive shaft if applicable.

Check the oil level and you are done.

 

[porkysplace]

Also probably a good time to check to make sure the axle vents are not plugged , or even run vent lines up to the air intake .

[h=1]923A2 differential vent[/h]

 

[lindsey97]

porkysplace beat me to it, remove each axle vent, soak and clean with compressed air. if they are stopped up, the axle will vent elsewhere like you are seeing. And that is a small seep, clean it with brake cleaner and drive the truck at least once per week to keep the seals wet.

 

[Grimm21]

Thank you all for the input I will be pulling the vents and cleaning them for starters to see if it makes a difference. When I took the posted photos I had already whiped most of the oil off the rear so it did look worse than what you see. After I take a long ride I will check again and if it continued I will go through the process of replacing the pinion seal and I will buy a couple for spares just in case I have to do it again. Thank you all for your help again

 

[Grimm21]

Update to my weeping issues I removed the axel breather valve it was not working. When I removed it from the axel there was a release of built up gases in the axel so the vent was definitely not working. I will run the truck this weekend and check for any other issues. Again thank you all for your help with this problem.

 

[Russ Knight]

Replacing the pinion seal is not that hard. I got my seals from bigmikem35a2 on Ebay for $15.95 each. I would buy a couple because if one is bad the others are probably not far behind. I have replaced 2 on my M818.

Read the TM first. I suggest using a 3/4 inch impact to remove and re-install the pinion nut. Use PB Blaster or WD40 if you have a hard time getting the pinion nut off.

The process is as follows:

Remove drive shaft if the flange the seal is leaking at is driven. Make a reference mark on the pinion flange and drive shaft flange so they get back together the same way.

Remove the cotter pin from the pinion nut. You need to be able to tighten the nut back to the same torque so make reference marks on all parts. Take a magic marker and draw a line across the pinion to show where the cotter pin is. Mark the pinion nut on the ears on each side where the cotter pin was on the nut, also mark the pinion flange.

Remove the pinion flange nut. The pinion flange should now just pull off. Check the pinion flange seal surface and make sure it is smooth. One of mine had some scratches that I had to sand out with some 1000 grit paper and buffing compound. If there is a lot of scoring you can have a new sleeve installed on the flange.

Remove the cover that has the seal and remove the seal. Clean the mating surfaces where the seal goes and where the cover mounts to the differential. Clean the mounting surface on the differential.

Put a bead of RTV where the seal goes and install the new seal. Check to make sure RTV has not gotten on the front of the seal; wipe it off if necessary. Apply a bead of RTV around the cover mounting holes. Re-install the cover on the differential.

Put a little grease on the seal lips and noting your alignment marks re-install the pinion flange. Re-install the nut and torque it down until the marks line up with the marks on the pinion. Re-install the cotter pin. Re-install the drive shaft if applicable.

Check the oil level and you are done.

Were there any shims behind the cover?

 

[Tow4]

Were there any shims behind the cover?

Not on mine.