LSD swap clarification

[rol1]

In the repair manual off of the homepage the LSD to 3.90 swap says that

 

Remove the side bearing caps and mark them(left and right).

 

Keep them with the rear end they came from.

 

You will need to reuse the 3.90 side caps with the 3.90 ring gear.

 

Make sure that you use the side caps that match the ring gear.

 

Very important as this will maintain your gear mesh.

 

If it isn't the right set you run the risk of getting noise and mismatch.

then the jpeg seems to indicate that the end caps are from the 3.70 (circled in blue).

 

[subieman]

Yeah use the end caps from the 3.7 LSD. Thats what I used when I did the swap. Everything seems to be working fine.

[Hondasucks]

you REALLY need to check the gear contact pattern whenever you mess with a differential. The side shims will set two things: Ring gear depth (How far in or out the ring gear teeth mesh with the pinion gear teeth) and carrier bearing preload. Here is what I would do: Count the # of shims on each side of both sets of caps. Let's say that the 3.90 open caps had 3 shims on one side and 4 on the other, and the LSD caps had 2 on one side and 3 on the other. Now, figure out what thickness all the shims are. Basically, you want to keep the same preload as the bearings on the LSD carrier originally had, BUT you want to keep the same backlash as the 3.90 ring gear had when it was bolted to the open carrier. So you'd want to use the LSD caps, with the same preload (5 shims total) but lets say that the 3.90 caps had 3 shims on the left adn 4 on the right, and the LSD caps had 3 on the left and 2 on the right, you would want to swap sides so that the opposite side has one more shim. Now, you'd use some prussian blue or gear marking dye (YOu can get this from GM) and coat 3-4 teeth, on both sides, in about 3 places around the ring gear. Using a pry bar between the case and the ring gear, rotate the pinion until the ring makes three turns, and then turn it the opposite way. YOu want the part where the dye rubs off to more or less be centered up and down and side to side on the ring gear. If it's not, you'll tear up the gears pretty quickly. (depends on how far off it is, but it doesn't take much.)

[rol1]

So does it matter if the original spacer rings and end caps are used, or just to use the same number of spacers as in the 3.7? But with the lean to same side as the 3.9?

 

I ask cause if all I need from the yard is the dif gear cluster without the ring gear, these window clerks might not know what it is, and I might get a deal, eh?

 

Do you guy's think I can get the LSD gear cluster fror $20 or less?:)

 

Is there a better way to check and set the run out and preload?

 

It's probably better if I just stick to plans a grab the end caps and spacers off the 3.70.