Diff Plug Size
Thread Starter
Instructor
Joined: May 2023
Posts: 122
Likes: 4
From: St. Charles, MO
Diff Plug Size
I was wondering the square size on this plug. Not sure if I can get a crescent wrench on it.
The Pinion has a leak. It was Topped Off 18 months ago and I'm not sure how much it's lost. So going to check it.
Is the pinion seal a PITA to do?
Tech Contributor
Joined: Aug 1999
Posts: 15,156
Likes: 3,965
From: Connecticut, USA
you have an oil leak at the plug. Try a 5/8 or 11/16 8 pt socket.
Pinion seal- need to seal splines, use a CR seal, set correct preload- too loose the pinion will crash into the case, too tight and the bearings is going south.
Pinion seal- need to seal splines, use a CR seal, set correct preload- too loose the pinion will crash into the case, too tight and the bearings is going south.
Thread Starter
Instructor
Joined: May 2023
Posts: 122
Likes: 4
From: St. Charles, MO
I plan on doing the steering box this winter and I plan to send it to you. Been searching and you are the guy for that.
Tech Contributor
Joined: Aug 1999
Posts: 15,156
Likes: 3,965
From: Connecticut, USA
Yes, it should be a 3/4 npt plug, they were used from 65-79, the 63-4 were a 1-20 machine thread and had leak issues. Get a tube of Permatex Green label gear oil RTV and use it on the threads. Do not use Permatex white high temp thead sealant, it acts like a thread locker and you will have to heat the plug to get it off. There were different size squares on these plugs, some have a "W" stamped in them as well.
Thread Starter
Instructor
Joined: May 2023
Posts: 122
Likes: 4
From: St. Charles, MO
Yes, it should be a 3/4 npt plug, they were used from 65-79, the 63-4 were a 1-20 machine thread and had leak issues. Get a tube of Permatex Green label gear oil RTV and use it on the threads. Do not use Permatex white high temp thead sealant, it acts like a thread locker and you will have to heat the plug to get it off. There were different size squares on these plugs, some have a "W" stamped in them as well.
Found the Green Stuff at Advanced Auto near me.
Tech Contributor
Joined: Aug 1999
Posts: 15,156
Likes: 3,965
From: Connecticut, USA
If the gear oil is unknown but you don't have any posi chatter when the diff is hot, taking a turn, then you just can top off the oil.
If you want to be proactive, suck out the old oil. put in 2 bottles of the GM additive, top off with Lucas gear oil. I use 85-140 but you can use 90wt too.
If you want to be proactive, suck out the old oil. put in 2 bottles of the GM additive, top off with Lucas gear oil. I use 85-140 but you can use 90wt too.
