Ring gear bolt loose (1 Viewer)

[mattolewis]

I took my truck out for a shakedown run and heard a big clunk from the rear of the truck, when I got home the rear Duff was leaking. Turns out the bolts on the rear ring gear had loosen up and this is what I found inside. Several broke bolts and the rest loose.

I plan to add a locker in the future but do not have the budget right now.

Questions:

Can I replace all the bolts and run it as is or do I need to rebuild the whole thing? There does not appear to be any gear tooth damage.

I have been doing some research on here and online and everything I find has a bolt and nut, but my ring gear is threaded so why do they come with a nut? Where can I find the right bolts? I want to buy a whole set to replace them all.

Thanks for the help.

 

[B y r o n]

What year is your FJ-40? As you mentioned, the ring gear in my '73 FJ-40 has a stud going through the ring gear and flange and is held in place with a nut as in this build.

 

[65swb45]

The threaded ring gear was used up until the middle of ‘72 IIRC. I have a box of used bolts; I don’t think new ones are available anymore.

The big question is why they came loose in the first place? In all the differential failures I’ve seen in 38 years of wrenching on cruisers, I’ve never seen that happen. Personally, I’d be spooked on that 3rd member and just move on to another. They’re readily available (I have 51 on the shelf at the moment)

www.marksoffroad.net

 

[charliemeyer007]

Measure the bolts and see what they are thread/length wise - then replace them all with correct bolts.
There is an off chance that someone just put in regular bolts and that's why they failed, or they didn't torque them with Loctite on clean surfaces.

I would plan on checking the pattern after the new bolts are in - just to make sure everything is fine.

 

[3_puppies]

we had a farm truck a few decades ago, early 70's Dodge that the front diff did the same thing.
we just welded the ring gear to the carrier, ran like that on the farm for many years before the rig was finally retired

with the ease of finding a replacement diff, easier to just swap it out for another

 

[Paul_A]

I bet the bolts that broke were way backed out and broke when they finally hit something in the housing. My gut says they were either slightly under sized replacements or not torqued correctly or both. In any case, if the gears and bearings are OK you dodged a bullet.

 

[ijonesinsp]

Too bad you aren't closer. I have a 3rd you could have for free.

 

[Mark Jennings]

View attachment 3486346
I took my truck out for a shakedown run and heard a big clunk from the rear of the truck, when I got home the rear Duff was leaking. Turns out the bolts on the rear ring gear had loosen up and this is what I found inside. Several broke bolts and the rest loose.

I plan to add a locker in the future but do not have the budget right now.

Questions:

Can I replace all the bolts and run it as is or do I need to rebuild the whole thing? There does not appear to be any gear tooth damage.

I have been doing some research on here and online and everything I find has a bolt and nut, but my ring gear is threaded so why do they come with a nut? Where can I find the right bolts? I want to buy a whole set to replace them all.

Thanks for the help.

View attachment 3486361

View attachment 3486363

Ouch!