Pinion seal replace

[RS Disposal]

Under  truck greasing what needs done I noticed that my pinion seal is wet.  Question is is replacing the seal pretty much straight forward as in with light trucks? Anything I should be aware of being I have never done a heavy truck pinion seal? 1979 Mack and I do believe it is the single reduction differential. Pretty sure I don't have a socket big enough so, off hand does anybody know the size needed I would need to purchase? Per factory shop manual looks like nut torque is 600-900 ft lbs.  Only reference to gear oil is "GO-F-90". An online search for that number shows it being 75W-90. Is this correct?

[mowerman]

im just a do it yourselfer cant help,,,im sure someone will chime in good luck,,bob

[RS Disposal]

7 minutes ago, mowerman said:

im just a do it yourselfer cant help,,,im sure someone will chime in good luck,,bob

I am more of a light truck/automotive mechanic. Getting my feet wet with heavy truck maintenance and repair

[Joey Mack]

How about a picture of the input shaft and the seal housing. I bet this is easy..  back then Synthetic was not used. Seems to me there was a 90 W mineral based oil.  I bet 80W90 oil would be just fine.  I also bet the seal can be popped out if it has a flange, or removed by puttin a sharp screw into the metal part of the seal and using a claw hammer or the like to pull the seal. Are you familiar with that method ? 

[RS Disposal]

8 minutes ago, Joey Mack said:

How about a picture of the input shaft and the seal housing. I bet this is easy..  back then Synthetic was not used. Seems to me there was a 90 W mineral based oil.  I bet 80W90 oil would be just fine.  I also bet the seal can be popped out if it has a flange, or removed by puttin a sharp screw into the metal part of the seal and using a claw hammer or the like to pull the seal. Are you familiar with that method ? 

not with the truck right now for a pic. I am familiar with that method of removing the seal. Just trying to get all my ducks in a row for when I do this job being when I have the truck at the shop I don't have my personal vehicle available whereas truck is staged at a different location for work

[mowerman]

11 minutes ago, RS Disposal said:

I am more of a light truck/automotive mechanic. Getting my feet wet with heavy truck maintenance and repair

Yeah, same here pretty familiar with auto  repair I usually have to get advice from here myself

[mowerman]

I’m sure there’s real thin shims between the ball bearing and the yolk that you don’t want to lose ha ha that’s about all I got

[Joey Mack]

Ok. Well as far as the seal housing goes, it should be easy to remove, the gasket is likley avaible, but you can cut one out of gasket paper, . Once you get the yoke out you will see if you need to do more.

[mowerman]

im sure your going to need a huge air wrench,,,good luck

[Joey Mack]

If he does use an air gun to remove or install the pinion bolt/nut, he needs to have the yoke held tight so that it does not hammer back and forth with the rythm of the air gun, otherwise he will risk damage to a gear or bearing. The intense backlash of an air gun can do harm...  and his final torque needs to be done with a torque wrench if possible..  

[mowerman]

Yes, I was thinking the very same thing about trying to do it with a big hand socket bar. That’s why I suggested air but yes. I guess in both cases you have to hold the yolk real tight with something getting somebody in there to give him a hand might not be a bad idea. I don’t even know if an inch drive air wrench will take out 600 pounds torque.

[Joey Mack]

I have a gun that will do it, but you still need to check it

[mowerman]

Yes, I was also thinking that how is he going to torque? It might be by the time he gets done renting tools you might as well. Just have somebody do it.

[mowerman]

You know if it’s a working truck just chalk  it up to business expense I believe that’s what he was asking in the first place can I do this myself?

[RS Disposal]

1 hour ago, mowerman said:

You know if it’s a working truck just chalk  it up to business expense I believe that’s what he was asking in the first place can I do this myself?

It is  a working truck and I have bought numerous tools that have been needed to do the work.

[Geoff Weeks]

Torque multiplier and a 1/2" torque wrench. That is how I do mine. Torque multiplier has a chart showing input (torque wrench setting) for desired output.

[Geoff Weeks]

BTW, unless that pinion seal is gushing oil, I'd put my efforts elsewhere before dealing with a "wet" seal. From what I saw of the airlines on the drier, that is much more likely to either get you shut down by DOT or leave you stranded. 

A damp or wet pinion seal that is not soaking the brakes with oil might get a mention on a inspection report but will not leave you stranded. You can check the oil and top off as needed, but a bust air hose leaves you dead in the water.

Also, how did you make out with the fueling issue? was that fixed when you replaced the hose, or are you still running the electric pump?

Edited 13 hours ago by Geoff Weeks

[RS Disposal]

10 hours ago, Geoff Weeks said:

BTW, unless that pinion seal is gushing oil, I'd put my efforts elsewhere before dealing with a "wet" seal. From what I saw of the airlines on the drier, that is much more likely to either get you shut down by DOT or leave you stranded. 

A damp or wet pinion seal that is not soaking the brakes with oil might get a mention on a inspection report but will not leave you stranded. You can check the oil and top off as needed, but a bust air hose leaves you dead in the water.

Also, how did you make out with the fueling issue? was that fixed when you replaced the hose, or are you still running the electric pump?

My truck deals with alot of snow and wet salty road slush that get frozen and packed into the frame rails and everywhere underneath.  Current have 1800 lbs of that according to the scale house at the dump.  It took me a day with a torpedo heater to get the fuel line to where I could get it out.  The fuel problem is still there so I have ordered a new lift pump and just replumbed the electric back in. 

The same issue is going to be changing out the air line from pump. In looking closer at the dryer and am pretty sure it is going to be junk from the corrosion from all  the road salt.  Going to pick up another one before I have the air lines made in case I need to route the lines differently.

After cleaning the frozen slush out from around the rear of truck I noticed that the pinion is leaking pretty bad.  Brake cans have oil on them.  In checking oil level it is lower than I would of liked to of seen it. Finger crossed I didn't mess up anything inside the differential.  Good time to do another gear oil change also.

My truck only runs about 150 miles a week with 2 trips across the valley of about 45 miles round trip.

[Geoff Weeks]

My point is still to focus on what is likely to shut you down, oil on brake cans isn't (unless the inspector is a real dick) Oil soaking brake shoes will. 

Air lines on the verge of failure will also get you shut down in an inspection even if they don't fail on the road and shut you down.

So why if it only runs 150 miles in a week, can't you address some of these looming problems? 

There is a lot of oil in a differential, part of the reason there is more than needed for lube is to cool.  A qt or two low isn't going to kill it. 

If it were I, I would pay a shop to do the pinion seal (as other have recommended) and use my time to address the other issues.

While a torque multiplier is a good tool to have when working on stuff that needs to be torqued higher than a 1/2 torque wrench can reach, it is expensive kit to sit on the shelf. It is much more versatile then a 3/4 or 1' torque wrench because you can use it in tight spots that the long handle on a torque wrench that can go 600 ft/lb+ can't be used.

Look, I know what it is like, I started with one truck, and had to prioritize repairs, I see big problems if you keep jumping problems without resolving any completely. I see real potential for a tow bill in your future, and trust me, you don't want that.

It would be cheaper to pay to have the job done than it would be to "Kit up" for this one job. 

[Joey Mack]

the yoke bolt on Mack rears torques to 550 lbft

[Geoff Weeks]

Still well into the range of at least a 3/4" torque wrench,  which is going to be damn hard to use while under a trash truck!

[Joey Mack]

trust me,  it's a tight work space.  back in around 2017 or so, the new pinion 'nut' arrangement had a bulletin out. they would come loose for no reason.. and of course Waste mgt and Republic had a bunch of the MRU chassis affected by this issue. We got our practice.  

[Geoff Weeks]

I doubt your air drier is compromised in any way, It is way thicker steel than the fitting are. Worse case buy a rebuilt bottom cover if that is badly corroded.  You can change that "in situ" with the drier mounted to the truck. 

Changing driers (when you don't even know if there is a problem) but saying you don't have time to do what is obviously bad, is poor priorities. You've got an air tap on the lower fitting, apply shop air to above gov cutout pressure and see if it pops off! While it is building up listen for air leaks, and spray the hoses with soapy water. 

If your going to make it on 150 mile/week, you got to spend your money wisely, I see you jumping at things without determining if they are the problem or not. 

[kscarbel2]

17 hours ago, RS Disposal said:

Under  truck greasing what needs done I noticed that my pinion seal is wet.  Question is is replacing the seal pretty much straight forward as in with light trucks? Anything I should be aware of being I have never done a heavy truck pinion seal? 1979 Mack and I do believe it is the single reduction differential. Pretty sure I don't have a socket big enough so, off hand does anybody know the size needed I would need to purchase? Per factory shop manual looks like nut torque is 600-900 ft lbs.  Only reference to gear oil is "GO-F-90". An online search for that number shows it being 75W-90. Is this correct?

Yes, 75W90 or 80W90 is fine.

I recommend Amsoil Severe Gear 75W90.