Cone style suregrip synthetic gear lube.

[AJ/FormS]

If you have a cone type, with a recipe of Non-Synthetic EP gear oil AND the Modifier, which is correct, and it slips.... Then it needs to be tested for turning torque.
If it is less than about 100 ftlbs, then it probably needs to come out for inspection, and if nothing else, tightened up.
If it is between 100 and say 110, then it may just have too much modifier in it.
If it is between 110 and 120, I use the modifier as a tuning aid.
if it is over 120 with skinny tires, it will act like a spool most of the time..
The turning torque that your unit needs, will depend on your power-level, what trans you are running, what tires you are running, and your driving style. Furthermore; in my experience, MORE modifier is not necessarily a good thing.
For example, I have a stout 360, a manual trans, 3.55s, and 295/50-15s. I like to Second-gear slide around corners about as often as I think I can get away with. My "posi" has to work, else stupid and or embarrasing chit happens. My combo likes 120 ftlbs turning torque, and to get that after internally tightening her up, she only needed a half a bottle of that oh-so-stinky whale-oil, for tuning.

 

[George Jets]

So does anybody know for sure if I will have to change out the synthetic gear lube? It is not a new unit.

I would change it out to 80/90 gear lube.

☆☆☆☆☆

 

[MOPAROFFICIAL]

Do you guys run synthetic gear lube in your cone style suregrips? I installed a 355 that has been sitting in a bucket for years. I used Valvoline synthetic gear lube and Red line friction additive. I only drove it about 5 miles but it is chattering going around the corners. Maybe it just needs drivin for awhile. What are your guys thoughts?

I run conventional
The cones can be touchy especially with mileage and not grab all the time

 

[sireland67]

I had the local driveline shop set up a set of new gears with a cone sure grip, and I asked him which fluid to run.
He said conventional gear oil, do not use synthetic.

 

[33IMP]

My friend who owned a rearend shop would NEVER use synthetic gear oil, on any job he did.
Torco only, bought it by the pallet-load.

 

[Dartnut]

Hello, I just picked up a cone style sure grip, Ive heard bad things about it and that occasionally it wont lock up. Are there any upgrades that you did to your sure grip or that guys have done to make them stronger and always lock up ?

I didn't do anything to the cone sure grip when I built the third member.
All I did was add a crush sleeve eliminator kit with new bearings, shims, and gears. (All from Dr.Diff)
Yes, I did use synthetic gear oil with the Ford friction modifier and the rear end locks up and does not chatter or make noise.
It works like it should.
If you choose not to use synthetic oil, that's up to you, but mine works great with it...