911 - stripped rear diff fill bolt leaking gear oil

[seanpistol]

Someone helping me do some maintenance on my truck today used an impact wrench to put the 15/16 rear diff fill bolt back in after we topped off the gear oil..... now it's stripped. It won't tighten or come out, just spins. I drove around the block and it's leaking gear oil. I'm supposed to drive the truck from Idaho to Oklahoma this weekend, so I need to solve this quickly.

What can I do to fix this?! Thanks for the help TS, you helped me change my timing belt successfully this weekend.

EDIT: I seem to be assuming that I stripped the threads on the diff itself and not just the threads on the bolt. What are the chances the threads on the bolt are all that stripped and I just need a new bolt?

[seanpistol]

Tomorrow morning I'm going to attempt to get the bolt out and then tap the hole to a larger size. Wondering if anyone has better advice than that, maybe speaking from experience.

[01TulsaTundra]

Tomorrow morning I'm going to attempt to get the bolt out and then tap the hole to a larger size. Wondering if anyone has better advice than that, maybe speaking from experience.

This is what I would do. You could always swap it out later if you feel uncomfortable with your new large tapped plug.

[UPbuilder]

Try wedging something under it and pry as you turn to get it out. Wood chisels work good for that, if you don't mind dinging them up.

[ZapcoTundra]

why in zuseus bunghole would you use an impact on something like that? hope you get it fixed!

[seanpistol]

This is what I would do. You could always swap it out later if you feel uncomfortable with your new large tapped plug.

swap it out later?

[UPbuilder]

If you can't save the threads you could weld a new bung right on top of the old one. 1/2" pipe plug would work for that.

[Highwaylizard]

Wow. Wooooowwwwww wow. Dude. Okay. I need a minute here.

Alright.

If you pull on the bolt with a pair of vice grips is it still holding in there? If so there are threads on the far end of the bolt inside the differential holding it in. If you stripped the threads on the differential housing I think the bolt would come right out. It may be possible to band aid this with some rubber and wire wrapped really tight between the nut head and the differential housing but I would not do that on my own truck and drive it.

I think you can back it out of there using said vice grips and two flat head screwdrivers wedged on either side while turning the bolt with the vice grips accompanied by a simultaneous outward pulling motion with the vice grips. Probably would be even better to have another set of hands to work the flat heads and keep them positioned.

Going to need to do a REALLY good flush of the differential to get any shavings out of there.

[SuckersWalk]

zuseus bunghole

if it doesn't clear up in a few days, you can probably get a shot for that.

[tundrunk]

My good buddy uses his impact gun to tighten everything... except when he helps me on my truck. I hide that damn thing, I hate them.

What Lizard said sounds reasonable, and if you are going to try tapping that out for the next size thread, be sure to change your fluid before you go driving it. I doubt it will leak enough fluid to cause any harm while driving, the fluid shouldn't touch that hole when cold at rest. When warm and splashing around, it shouldn't leak an amount that will cause harm.

Good luck, this sucks knowing you just got your truck back from that accident.

[seanpistol]

If you pull on the bolt with a pair of vice grips is it still holding in there? If so there are threads on the far end of the bolt inside the differential holding it in. If you stripped the threads on the differential housing I think the bolt would come right out. It may be possible to band aid this with some rubber and wire wrapped really tight between the nut head and the differential housing but I would not do that on my own truck and drive it.

I think you can back it out of there using said vice grips and two flat head screwdrivers wedged on either side while turning the bolt with the vice grips accompanied by a simultaneous outward pulling motion with the vice grips. Probably would be even better to have another set of hands to work the flat heads and keep them positioned.

Going to need to do a REALLY good flush of the differential to get any shavings out of there.

It's in there. I am pretty confident I'll be able to get it out by prying it and using a wrench simultaneously, then replace the plug with a new one from the stealership. I won't band-aid it. Good thing I have a bunch of gear oil sitting around for a flush... I'll let ya guys know how it goes.

[Stone_Blue]

Since you are getting ready for a long trip, and are time strapped, I woulda suggested cleaning around the bolt head real good with acetone or something, then using JB Weld or similar to seal around the hex of the plug....Or maybe even just use RTV....THEN worry about a permanent fix when you get back.

I bet BOTH the threads on the hole, AND the bolt threads are stripped, and like Highway said, the threads further down the bolt that are now past the hole threads, are what is keeping it in.
Cuz if the threads in the hole were NOT stripped, you SHOULD be able to pry out on the plug, and get it restarted coming out. But if that doesnt work, I bet both sets are stripped, or at least definately the ones in the hole. There are only a few threads in the hole, making it easier to strip than just the ones on the bolt alone.

And, Man, that really sux!....Yeah, that diff plug does NOT need a whole lot of torque AT ALL!!

[seanpistol]

Problem is fixed.

Got the fill plug out with vice grips. Wasn't able to wedge anything behind the plug while it twisted. It appeared to be that just the outer two threads of the diff were damaged, and the threads were smashed flat on one whole side of the plug.

Bought a new plug and a set of taps. Tap size for the threads in the diff is 18x1.5 for anyone looking in the future. Drained and refilled the gear oil, ready to go.

[jack mccarthy]

Someone helping me do some maintenance on my truck today used an impact wrench to put the 15/16 rear diff fill bolt back in after we topped off the gear oil..... now it's stripped

I want to see the vehicle your friend there drives. Anyone using an unregulated impact wrench on a drain/fill plug probably has more problems on their vehicle than yours!

[seanpistol]

I want to see the vehicle your friend there drives. Anyone using an unregulated impact wrench on a drain/fill plug probably has more problems on their vehicle than yours!

Surprisingly he is a mechanical engineer that drives a pristine 1984 diesel F-250 that he has done all the work on. He knew he goofed up and we fixed it so I'm not mad. I guarantee he won't use an impact to tighten anything again.