V2 Diff rebuild + Gear Ratio Swap

[bigjae46]

If I were to use all RD items (same number of steels and clutches), this would give a theoretical value of 18mm!!! no way we can fit all of that in the unit. as mentioned above, the clutch pack gear (what I called spacer gear before) has an effective height of 16mm! More than that and you will likely have a lot of preload and risk the first clutch plate to crack by the piston pump, or wont be able to close the unit at all.

I think RD's deal here is the steel/clutch stack will be thicker so it acts like a mechanical clutch diff. The reason being that the viscous pump wears out and no longer engages to the press the clutch stack together. Try reaching out to RD and see if that's normal?

[maupineda]

Hi Heinz, not really. I have learned something interesting about the viscous pump. But want to document it first before posting about it.

i did have to work (force) the clutches in to mesh and slide onto the spacer gear, but fortunately for me, I did not have to file any teeth.

[heinzboehmer]

As shown in the pictures, the thicknesses are a bit less, so I am assuming the above for new items. so that leaves the stack height at 14.4mm

If I were to use all RD items (same number of steels and clutches), this would give a theoretical value of 18mm!!! no way we can fit all of that in the unit. as mentioned above, the clutch pack gear (what I called spacer gear before) has an effective height of 16mm! More than that and you will likely have a lot of preload and risk the first clutch plate to crack by the piston pump, or wont be able to close the unit at all.

Your experience seems in line with this: https://nam3forum.com/forums/forum/m...ue-and-contact

[maupineda]

I measured the V2 kit for GKNV2 unit

Steel Plates - 1.03 mm (5)



Thick steel plate: 2.02mm (1)



Clutch plates: 1.1mm (5)



Total stack based on Individual component values - 12.67mm

The big spring washer that goes on top of the stack and between the lsd pump is 4.6, and can compress flat to 2mm

so total value is ~17.27mm (uncompressed) or 14.67mm (compressed)

I also calculated the load the washer needs to compress flat and is 3300N or 320kg (~700#) of force which is meaningful, however without knowing the pump capacity I don’t know if this is much or not; hydraulic pumps have high force capabilities, so if we make an analogy to a car jack, you get the idea.

the “free shim” washer needs 2000N to go flat, so I don’t like that much preload for the spider gears. So I will go with flat shims and leave some slack (0.1mm).

To document things a bit further. Bellow is the thickness of the OE items, mileage on this diff is unknown.

OE Steels are ~.8mm
Clutches are ~.9mm

As shown in the pictures, the thicknesses are a bit less, so I am assuming the above for new items. so that leaves the stack height at 14.4mm

If I were to use all RD items (same number of steels and clutches), this would give a theoretical value of 18mm!!! no way we can fit all of that in the unit. as mentioned above, the clutch pack gear (what I called spacer gear before) has an effective height of 16mm! More than that and you will likely have a lot of preload and risk the first clutch plate to crack by the piston pump, or wont be able to close the unit at all.

OE steel plate



OE clutch plate

[maupineda]

C'mon man! Swap that purse for a hammer and whack it! Its hardended steel! lol Seriously, you can whack it if its stuck.

Those spider gears look the same as all of the ones I've seen. I think the come with a crap finish from the factory. I wonder if REM polishing would make some kind of improvement.

Thanks for confirming is normal. Tbh I was expecting a better finish..

[sapote]

I wonder if REM polishing would make some kind of improvement.

Improve what?

[bigjae46]

I then tapped on the edge of the ring gear which is large enough for a flat screw driver, then hammer it out. It does not take much, so the taps can be gentle. Once the ring moves then loosen the bolts a bit more and do another round of taps, then I just remove the bolts and tap until the rings falls off. I put a rag at the bottom of the card box to not smash the ring gear as it falls off

C'mon man! Swap that purse for a hammer and whack it! Its hardended steel! lol Seriously, you can whack it if its stuck.

Those spider gears look the same as all of the ones I've seen. I think the come with a crap finish from the factory. I wonder if REM polishing would make some kind of improvement.

[sapote]

Your posted side gear pic looks normal. They turn slowly and only during a turn, so causing low noise. They are not polished as transmission gears which are turning at higher speed and all the time while driving.


Foods for thought: V1 has the 4 spiders gears floating as the two shafts are not locked in the holes as compared to V2 with the 2 shafts are in the holes with C-clips.

RD removed all side-gears and spiders backlash which causes the infamous clunk noise using the spring washer. The same spring washer only removes backlash on one side-gear and 2 spiders (one the spring washer side), as the other side-gear and 2 spiders are not affected, because the shafts are locked and not floating as V1.

[maupineda]

Continued with the diff work, cleaned all the internals.

I found that the spider gears are not in the best shape. Thoughts?

[sapote]

The pump has to be pressed in until it bottoms out, is a light press fit into the carrier.

Did you verified the pump housing bottomed out on the carrier or just a guess? It might be bottomed out with a used worn clutch stack, but I don't think it bottomed out with a brand new diff from factory as this would mean impossible to preload the breakaway torque.

I believe the clutch stack total thickness must be dimensionally adjusted, with shim if needed, in order to achieve the spec breakaway torque.

[sapote]

All new clutch stacks have different thickness due to production process. With a fixed pump and no shim to adjust the clutch preload, I think we’re missing something here.

[maupineda]

Interesting of why they used a spring washer between the pump and lock-ring; why not have the lock-ring directly pressing on the pump? The spring would allow the carrier bearings to float outward, in theory.

With the pump removed, did you verify that the lock-ring can be turned in passing the locking ball?

It may, but no point in trying it. The pump has to be pressed in until it bottoms out, is a light press fit into the carrier.

you can see the ring collar and the spring washer below.

[maupineda]

I was able to remove the ring gear. All I needed was a larger impact. No issue with the carrier spinning on your hands.



I remove all but three bolts and just loosen them to have a few mm of gap to the carrier unit.



I then tapped on the edge of the ring gear which is large enough for a flat screw driver, then hammer it out. It does not take much, so the taps can be gentle. Once the ring moves then loosen the bolts a bit more and do another round of taps, then I just remove the bolts and tap until the rings falls off. I put a rag at the bottom of the card box to not smash the ring gear as it falls off

[maupineda]

The pump housing (and its static center) is bottomed on the carrier step, this means the space between the 'spacer gear' and the side-gear (the two side-gears and the 4 spider gears are what you called 2 spiders and 4 planetary gears) defines the backlash.

There is no shim between the pump and the clutches stack? The pic below seems to show the arrowed plate is a shim or spacer as it has no teeth inner or outer. No?

No shims between the pump and the first steel plate. What you perceive as a shim is the steel plate, you can see the teeth, just cover in oil and clutch material grime.

[sapote]

The pump housing (and its static center) is bottomed on the carrier step, this means the space between the 'spacer gear' and the side-gear (the two side-gears and the 4 spider gears are what you called 2 spiders and 4 planetary gears) defines the backlash.

There is no shim between the pump and the clutches stack? The pic below seems to show the arrowed plate is a shim or spacer as it has no teeth inner or outer. No?