RS Disposal Posted 3 hours ago Share Posted 3 hours ago 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? Quote Link to comment https://www.bigmacktrucks.com/topic/76361-pinion-seal-replace/ Share on other sites More sharing options...
mowerman Posted 3 hours ago Share Posted 3 hours ago im just a do it yourselfer cant help,,,im sure someone will chime in good luck,,bob 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76361-pinion-seal-replace/#findComment-590197 Share on other sites More sharing options...
RS Disposal Posted 3 hours ago Author Share Posted 3 hours ago 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 Quote Link to comment https://www.bigmacktrucks.com/topic/76361-pinion-seal-replace/#findComment-590198 Share on other sites More sharing options...
Joey Mack Posted 3 hours ago Share Posted 3 hours ago 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 ? Quote Link to comment https://www.bigmacktrucks.com/topic/76361-pinion-seal-replace/#findComment-590199 Share on other sites More sharing options...
RS Disposal Posted 2 hours ago Author Share Posted 2 hours ago 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 Quote Link to comment https://www.bigmacktrucks.com/topic/76361-pinion-seal-replace/#findComment-590200 Share on other sites More sharing options...
mowerman Posted 2 hours ago Share Posted 2 hours ago 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 Quote Link to comment https://www.bigmacktrucks.com/topic/76361-pinion-seal-replace/#findComment-590201 Share on other sites More sharing options...
mowerman Posted 2 hours ago Share Posted 2 hours ago 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 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76361-pinion-seal-replace/#findComment-590202 Share on other sites More sharing options...
Joey Mack Posted 2 hours ago Share Posted 2 hours ago 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. Quote Link to comment https://www.bigmacktrucks.com/topic/76361-pinion-seal-replace/#findComment-590204 Share on other sites More sharing options...
mowerman Posted 2 hours ago Share Posted 2 hours ago im sure your going to need a huge air wrench,,,good luck Quote Link to comment https://www.bigmacktrucks.com/topic/76361-pinion-seal-replace/#findComment-590207 Share on other sites More sharing options...
Joey Mack Posted 2 hours ago Share Posted 2 hours ago 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.. Quote Link to comment https://www.bigmacktrucks.com/topic/76361-pinion-seal-replace/#findComment-590209 Share on other sites More sharing options...
mowerman Posted 1 hour ago Share Posted 1 hour ago 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. Quote Link to comment https://www.bigmacktrucks.com/topic/76361-pinion-seal-replace/#findComment-590212 Share on other sites More sharing options...
Joey Mack Posted 1 hour ago Share Posted 1 hour ago I have a gun that will do it, but you still need to check it Quote Link to comment https://www.bigmacktrucks.com/topic/76361-pinion-seal-replace/#findComment-590214 Share on other sites More sharing options...
mowerman Posted 39 minutes ago Share Posted 39 minutes ago 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. Quote Link to comment https://www.bigmacktrucks.com/topic/76361-pinion-seal-replace/#findComment-590215 Share on other sites More sharing options...
mowerman Posted 34 minutes ago Share Posted 34 minutes ago 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? Quote Link to comment https://www.bigmacktrucks.com/topic/76361-pinion-seal-replace/#findComment-590217 Share on other sites More sharing options...
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