Does anyone know what that plug is for, hanging on the Diff cover? A friend just bought the car.

 

I suspect if your friend removes the ULTIMATE name plate he'd get a better indication of its purpose. I can see a piece of twisted wire remains on the LH-side of the ULTIMATE name plate, as well.

 

Noticed that too. The car's in the body shop, so when he gets it back he'll go through it. Just wanted to know if anyone has any ideas as we're too impatient to wait.

 

I didn’t really want to start guessing, but I will. The possibility of an electric trailer brake wiring plug/connector. Anyone’s guess.

 

The ULTIMATE diff cover uses rods that go almost out to the backing plates to improve the suspension/traction. That looks like one of the inboard connectors that would attach to the rod. I'm guessing it was put there for completion of the job and I'm guessing that the left one is well...missing somewhere on the highway. Remember I did say I'm guessing...

 

Actually, if you zoom in to the left one, you can see it peeking its "head" at the bottom of the ULTIMATE logo. This is going to drive me nuts.

 

A cheap and easy ground is my safe bet. Long shot is ELECTRONIC LOCKER OHHHH YEAH.

 

I was thinking a temp sensor connector, but not sure why you'd need two connectors (2 are not needed for an e-locker diff either). Are you sure these are electrical connectors and not fluid connectors? Back in the day it was popular (in some areas) to bolt 2 small red lights at the bottom of the diff (god only knows why). Maybe these are left-over pieces of wiring from that?

Last guess: Reluctor ring for some aftermarket traction control? Didn't some Buicks use a crude-form of traction control in the early '70s that interrupted the ignition when tire slip was detected? Again, not sure why you'd need 2 connectors for that.

 

Ding ding ding. I'll bet you nailed it, John. Either electronic, manual or air actuated locker cable connector.

 

looks like Sugar Bear nailed it.
https://www.lpwracing.com/Ultimate_GM/Ultimate_GM.html

 

I don't believe that addresses the OP's question regarding the plug itself.

 

Oh, I see what you're saying - my bad. The end piece of the suspension rod itself. I gotcha. It will be interesting to see what it is. I'm kind of suspect as to the reason behind the twisted wire remaining on the LH-side. Oh well, kind of interesting.

 

I guess I'm too thick between the ears...I don't see any advantage to those rods in relation to Improved traction and handling...

 

The twisted wire is simply securing the loose end of the fitting that is still attached to the cover to keep it from flopping around. You can see the fitting on the left side peaking out from between the cross-bracket and the cover (its there if you can zoom in to see it).

That strut is simply triangulating the tube-to-housing weld and taking some load off it (as if that is a weak part). It can't do anything about the moving parts of the rear suspension. The vast majority of the forward force generated by the tires is transferred to the car's frame via the LCAs, not through the diff housing.

 

Brilliant you guys (Sugar. 4peed, sammi & Johnny). I failed to see it in its parallel orientation to the ULTIMATE nameplate. Great detective work.

 

On drag cars with sticky tires, launching the car will actually deflect the axle shafts forward, causing tow-in of the rear tires and potential loss of traction or stability issues. The rods turn the rear axle into a truss in the horizontal plane, mitigating that deflection. Of course, as designed, the resulting truss isn't deep enough to be useful, and the slop itn the fasteners means that the struts don't pick up enough load to be effective, but that's a different problem. Most people who design and purchase these products are not engineers.

 

Wow, I've never seen anything like that before. Learned something new, though I can't see any advantage to it, maybe they sold cuz they look cool???

 

Thanks Joe, I can now visualize the intended concept, but l agree it wouldn't help with a car of this caliber. In fact, cars with enough traction and horse power to deflect the rear axle casings are already built for those loads anyway.

 

I thought we were talking about the electrical plug there.

 

Its not an electrical connector, its for the rod end

 

OP said plug?