8.75 suregrip problems

[DirtyDawg]

I bought a supposedly new suregrip, and after I installed it and ran it awhile it started chattering a little when turning under power, when I would pull off from a stop, I put pos additive in it when I installed it but I went ahead and put another bottle in it. It only got worse, sometimes it feels like the rear is shifting forward and back, everything is tight on spring perches. Finally just took it out and tore it apart to inspect it, at first everything looked good but after digging deeper the inside of the case has some ware and I don't think the clutches are right, there are no dished disc, but does have the dished plates. What I need to know is my case alright and do I need new clutch kit.

Looks like back side of spider gears and side gear retainers are wearing into the case.
Whats going on?

 

[DirtyDawg]

I bought a supposedly new suregrip, and after I installed it and ran it awhile it started chattering a little when turning under power, when I would pull off from a stop, I put pos additive in it when I installed it but I went ahead and put another bottle in it. It only got worse, sometimes it feels like the rear is shifting forward and back, everything is tight on spring perches. Finally just took it out and tore it apart to inspect it, at first everything looked good but after digging deeper the inside of the case has some ware and I don't think the clutches are right, there are no dished disc, but does have the dished plates. What I need to know is my case alright and do I need new clutch kit.

Looks like back side of spider gears and side gear retainers are wearing into the case.
Whats going on?

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[AJ/FormS]

Trac-locs behave differently than SureGrips.
They lock up with power application and sorta freewheel when the power is off. The builder sets the slip point with clutch pack preload. If or when the clutch pack wears out, it becomes like an open diff.
You see how the cross-pins have flats on them that match flats in the case? those are actually ramps. As more and more power is applied,with tires not spinning, the case forces the pins up the ramps which increases the clamping force, making it a sorta spool. When you remove the power, you're left with the builders clampload.
But in your case the spiders seem to be jamming into the case looks like because the case radius is different from the spider gear shoulder radius. I have not seen that before.
So, I have to conclude that those spider gears don't belong in that case, as they have been installed.
As to the crosspins they appear to be a lil short on one end, but could be normal. They should have a separator block and a pair of button-head thrust-pins holding them together. The buttons rest against the axles and transmit a solid dimension with which to set the axle endplay.
As to the clutches, they should all be flat except the two dished ones, which are the springs, and IIRC they go 4th ones on, which should be second last,and install looking like saucers. And they should be alternating steel and friction.
The whale-oil additive is used to fine tune the slippage, and to eliminate chatter. More is not necessarily better. I start mine off with half a bottle. Never more than a full bottle. I mix the EP oil and the Whale oil, and presoak the plates. Then I assemble it all and adjust the clampload to get ~110ftlbs minimum turning torque; not breakaway torque. I don't think there is a spec for this, but I have found that 120ftlbs works well on the street for me, with BFG 275s or larger.