Clunk, Pop and Whine goes the differential

[djhedges]

That's the sound that came from the rear of the car as I came around the "half pipe" turn at Oregon Raceway Park. Immediately I put the clutch in which made the whining noise go away and got a flat tow back into the paddock. Jacked the car up and with the transmission in neutral the rear wheels will spin forward but lock in reverse. We disconnected the rear shafts so we could get the car off the trailer once we got home. This weekend I plan to drop the diff and start poking around.

Has anyone seen this issue before? I tried searching but I keep finding posts about doing donuts instead of diagnosing differential issues.

Anyone have of a good link for identifying what kind of differential I have? The car itself is a race prepped car I bought from someone else and I'm just starting to learn about Zs.

Here is a plug and picture of the turn at ORP. We were running anti-clockwise and I was transitioning the weight when it went. I think I was hearing the clunking around other turns as well but I'm still learning the car so I haven't quite figured which noises are good and bad yet.

[Zed Head]

If you describe the year and model of car someone might have an idea. Pictures are always good too (of the differential, not the track).

[djhedges]

Heres the damage. My guess the safety wire went at some point and a bolt was able to wiggle it's way out.

The new diff that went in. Question about the vent? at the top of the diff. Does that need some sort of cover is it fine to run it like so?

The old diff. Any thoughts on having the diff rebuilt vs buying another used one?

Thanks for your help.

[zKars]

That's an R180 diff. Don't know what its from. That K on the case is a clue, I remember someone discussing that recently. Subie maybe? Is there an LSD unit in the case?

The vent on the new one looks like a brass pipe fitting that's been epoxied in. Likely had a hose of some sort attached that performed the vent function. It has to be open (to be a vent) but must prevent moisture and debris from entering.

What's facinating about your old diff is two things. There appears to at least 3 missing ring gear bolts (is the center one sheared off?), and is that the remains of one of the ring gear bolts stuck through on the casting web on the rear cover?!?!?!?! (picture 2)

[djhedges]

Out of curosity what tipped you off that it's a R180 diff?

According to the notes I recieved with the car it's an LSD. This is my first time opening up a diff so I'm still learning.

The pictures are a bit misleading. We removed some of the ring bolts by hand that were loose along with broken saftey wire. The center bolt is sheared and the other half was found in the cover. The metal drain plug also had a good amount of metal shavings but I didn't notice much in the fluid as it drained.

[zKars]

The shape of the cover is the give away for me, and then the overall size. The rear covers of the R160/180/190's are quite rectangular, while the R200's are much closer to round.

Makes you wonder how only one bolt shears off. Were any of the other bolts loose? Maybe they weren't torqued correctly, or that one was way too tight, or was damaged from a previous over torque. Might be worth an inspection of the other bolts before re-use or just get new ones.

R160 R180 R200

Edited September 10, 2013 by zKars

[Zed Head]

The one that broke could just be an open diff that broke its spider gear shaft (might be called a pinion shaft also), and the broken piece bounced around and tore up some wire and a bolt head. I had one shoot completely out of the diff, on a GM car. Left a scary looking hole in the diff cover.

A picture of the differential itself from the other side of the ring gear might show something. Take one each of the broken and the new/old.

[djhedges]

I took the diff apart and found some metal pieces. I'm currently looking for a set of these ring bolts and I'm not having much luck. Any suggestions?

I stopped by home depot to measure it and it's a m10 1.25. I did think of pulling one out of the welded diff but they're different. After thinking about it maybe it's not such a good idea to reuse ring bolts.

[EuroDat]

Why not buy a full set from Nissan? There are two part numbers available. P/N: 38102-22900 (€2.43ea) and 38102-P0100 ($2.80ea)

I dont know what the difference is and not knowing which car your diff originally came from doesnt make it easier. Maybe the parts guy at your local nissan dealer can help you sort out which one to use. Or just buy 8 of one P/N and fit them.

Chas

[jmortensen]

So you had this safety wired and you still lost the bolts? That's a pretty rare failure to begin with, but much weirder if they were really safety wired in to start.

I wouldn't bother rebuilding the diff. Just get another one. As to the ring gear bolts, I've always reused them with no issues, but they're cheap enough that one could definitely justify the expense.

[Carl Beck]

From memory - there are 10mm and 12mm ring gear bolts. Depends on the year of manufacture. Or was that just with the R200?

Secondy - I believe that the rear ends with the large "K" cast in - were built with 4 spyder gears. I think that was the difference between the regular production units and the Nissan Comp. units. The Comp units having 4 spyder gears in an open diff.

It will be interesting to see what is inside that new unit..

FWIW,

Carl B.

[John Coffey]

The ring gears in the R180 are 10mm until sometime in the mid 1980s when they went to 11mm. There's a post on Hybridz where I list the exact date of changeover. "K" housings normally contain a two pinion open diff although some 4 pinion open diffs were used, although I don't know the application. All the 720 truck, Maxima, and 200SX R180 K units I've seen were two pinion open diffs.