Disconnecting the battery is to prevent damage to electronics. The electrical system is designed to conduct electricity but current and voltage out of its design parameters can damage it and its components.

Bearings can be damage by the welders current path. If you are welding on the right frame rail and the ground clamp is on the left frame rail the current will cross the truck somehow. If welding across the diff chances are the current would flow through the case and not affect the bearing but s@#$ happens.

So disconnect the battery and keep the ground clamp as close to the welding as possible.

 

I would ask if they used a case spreader when installing the carrier. I know I am going to get flamed for this comment, but it is impossible to get the correct bearing preload, especially on new bearings, on a D60 or 70 without the spreader. Bearings are pressed on and shims are between the bearing and carrier case, not between the bearing and the diff housing. Lots of people do it without the spreader, but a "real" diff shop should
be using one. That's why it is so hard to get the carrier out if it has been assembled with the correct preload.
OK, I am ready fo get torched, let it fly.

 

Hey Sam!

Greetings from North Dakota! I spent some time in Lincoln recently getting one of our King Airs worked on…I should have pinged you.

Regarding the Sterling 10.25, they were in the “Heavy Duty” until the end of 1997. Beginning in January 1998 the Super Duty entered production with the metric bolt pattern. There may have been some 10.25s made in 1998 still for OBS cab/chassis, unknown.

1994-1997 OBS 250/350 should narrow the search for a 10.25. I just picked up a 1997 250, 7.3, 5 speed and it has 4.10s. Seems like a really solid axle and I just did a brake job on it. Had to pull the drums off a couple times for some e-brake cable stuff, and the outboard drums are worth the swap alone, IMHO. I would have lost my mind pulling the hub every time like on my old D60. Highly recommend looking for a 10.25, versus fixing the D60.

I can measure the perch width on both trucks if you like. I am pretty sure the 1997 has a wider frame in back.

 

Thank you all for the welding precautions info and for the good info on Sterling axles. I keep snippets of information like this in a list so I can remember what to do when I can get around to doing it.

The d60 is an antique but I have it up and running. Not ideal I suppose but I am committed to rebuilding this 4bt and am avoiding a mess of junk projects. If it doesn’t work it’s junk!

Cbrown, how do WMS’s vary between the d60/ 10.25? I’m guessing perches would need done for the swap. On your front HP, did you have to redo your driveshaft for angles with the HP or did your transfer case swap fix that? PM me if/when you’d be in the Lincoln area and if I’m not tied up it’d be great to meet up for an adult beverage!

Question for the 78-79 D44 HP guys: I get a lot of gear oil coming out of the breather tube. Tube comes off breather fitting, goes up and loops towards the rear and back down. Should I drill out the fitting? Is this normal?
Sam