Front diff - Misaligned? Driveline issue?

While inspecting my truck to further identify why my passenger CV failed on the trail not so long ago (the incident: https://www.tacomaworld.com/threads/passenger-side-half-shaft-broke.722269/ ), I came across the rear mount/bushing for the front diff.

The fastener is misaligned and sitting at an angle, so it would appear as though something shifted. It's hard to tell from the pictures, but I would say that the fastener is sitting at a 10-15 degree angle from vertical. That being said the two front mounts appear fine--nothing tweaked or loose. No frame damage either.

Has anyone else seen something like this before? Or is this within the normal range of flex of the bushing?

From the bottom:


From the side:


Top of the bushing:




Front mounts:

 

Looks normal to me. Perhaps just shifting due to normal torque. If you’re worried you can loosen all them up and torque all the bolts to spec.

 

Yeah, it's definitely more noticeable in person, the pictures don't show the 10-15 degree angle so well.

Just trying to nail down what could have caused the shift as, aside from the bushings, everything is rigid.

Thanks for the input.

 

Yeah pictures don’t do those kinds of things justice. Have you checked torque values to see if everything is tight? Did the bolts that hold the mount to the diff loosen up possibly?

 

Didn't have time today, but I'll check tomorrow morning and report back.

 

Meant to respond to this a while ago--wanted to follow up.

Loosed all the diff mount bolts up and re-torqued. When the rearmost mount nut was removed, the stud looked like it was pretty well aligned. But when I tightened it back up it went back to its off-center position. Maybe we the bushing has gone bad? All other fasteners were properly torqued.

I took some very rough measurements from diff housing to hub on each side and found that the PS is about 5/16 further out than the DS (which matches up with the direction that the rear mount stud is tilted).

Nothing bent, broken, or damaged as far as I can tell. Still investigating why it seems to be so off. Will continue to update this thread if I find anything.

Let me know of anyone has any ideas.

 

Follow up to this, trying diagnose other issues and rule things out.

Anyone have pics of their rear mount for the front diff (similar to what I posted above)? Want to try to get a baseline.

 

Do you have a diff drop installed?

(post pictures of the front two mounts)

Otherwise this looks normal to me the cross members are welded onto the frame with manufacturing tolerances (read "close enough") so that's why the rear mount is ovoid instead of true round to allow for tolerance, you may just have a cross member welded in at the extreme end of acceptable and a diff at the extreme end of length for acceptable.

So long as everything functions I wouldn't worry about it.

 

Thanks for the input.

No diff drop installed.

I can get a few better pictures of the front mounts tomorrow.

And, yeah, I haven't had any issues (that I know of) that this is a cause or result of. It's more just my engineer side trying to find a root cause. I blew out my PS CV shaft a little while back (half shaft popped out of the stub shaft cup and grenaded itself), which lead me to do a more thorough inspection of everything drive line and suspension related under the truck. While I don't think this is directly related, I still want to figure out exactly what's going on here, for my own edification at the very least.

Going to keep digging/measuring/etc. until I figure it out!

 

Are you using OEM axles?

Lifted at all?

Still have your sway bar installed?

Limiting straps installed?

What were you doing when your CV gave itself the ol' Yeller?

From what I can see of the front mounts it doesn't look like you have a diff drop, if you do it's a small one like 1/4 inch.

On the 1st gens the general consensus is a 1" diff drop is mandatory if you're lifted, for 2nd gens the party is divided right down the middle, that's why I have a 1/2" diff drop cause I'm a fence sitter who can see both sides and I think the grass is equally green.

 

Axles and what was happening when the axle failed: Not stock. Bought the truck with non-OEM axles, which I discovered when the PS axle failed. The axle busted when I was bumping the truck up a moderate feature in 4LO, nothing I would consider extreme, but also not "easy". Replaced with good ole NAPA's, which I have been happy with so far.

Original "help" thread when the axle gave me the big ole' FU and stranded me on the trail: https://www.tacomaworld.com/threads/passenger-side-half-shaft-broke.722269/

The PO had replaced both CV shafts with some el-cheapo parts. The first hint was a 36mm axle nut, but the real kicker was, while replacing both axles, come to find out, that they were ~1-1.25" shorter than OEM length (measured against a friend's OEM axles; worth noting that the NAPA axles that are on the truck now match OEM length). I attributed this difference in length to the failure. I surmised that the shorter length worked fine at stock height, but became an issue when I lifted the truck.

Lift: Dobinsons shocks+springs up front. Should lift the front 2-2.25" based on the specs given. Actually lifted the truck 2.5-3.0" based on measurements--I assumed the stock springs were sagging (the front shocks were pretty beat). Dobinsons shocks and AAL in the rear.

Sway bar: Hasn't been installed for a while.

Limit straps: None.

 

More images of the front mounts. They appear to be A-OK.

 

Same thing happened to me except mine is jumping into my transmission and grinding it when I let the clutch out hard ,Help ?

 

Same exact thing is happening to mine, but only when I start to go in 4 wd, then it seems to calm down.
I have a second Gen that is crazy modified. I will check that alignment nut and see if it is hosed, if so, I will replace

 

ok. update, I think I have this sorted.

for my situation, that rear mount point that bolts to the frame is cracking away. it looks like at one time I had placed a washer there, but the frame region that holds that nut in place cracked and for sure pulled the wahser through.

I put a larger thicker washer there, and that seems to have done the trick. no more tranny grinding

also, frequently the driver side diff bolts will back themselves out, so I have to constantly tighten those.



Hope this helps someone with this issue.

 

Nothing wrong with how it's bolted up.

 

https://www.tacomaworld.com/threads/urban-ops-prerunner-to-4x4-build-journal.772226/page-2 Post #31

 

I think that @nudavinci64 mod? I know its @weldstaco on instagram

 

Weldstaco on IG kit.

 

What did I do? =)