Replacing crown gears on final drive - r90 project

[shannonnunley]

Originally posted by roger albert
Sounds doable for you guys Shannon. Half of the game is not being easily intimidated and being patient and perseverant, so it IS doable, just not fun or easy. The gear spacing "mesh" is the tricky part. Have you ordered a selection of shims for the main bearing?

In any event, it is to me inconceivable to go to all that work and not replace those seals. It is rare for anything to go wrong back there that isn't a seal. At the very very least, the pinion seal and packing should be replaced, as it's buried behind the gear/washer/nut etc. When that seal goes, then the driveshaft fluid can run down into the rear drive.
You end up with a messy/spewing rear drive, and a dry/non-lubed driveshaft, neither of which is particularly desireable.

Good luck!
Roger

K, I orderded the seals per your advice.

Haven't ordered any shims, but will if what we have doesn't work.

[tvrla]

the round gear is worn, which means I have to replace the rest of the gears. I'm replacing the gasket, but the seals all look good.

Describe the 'round gear' to me. The pinion is the one connected to the driveshaft. It's got 11 or 12 teeth. The ring gear looks like a ring and has around 33 teeth. Attached, and part of that gear, are the splines that mate to the splines in the rear wheel hub. Generally the ring and pinion don't wear. Just the splines.

Are you saying that the ring gear is worn? Could you post some pictures of this part and the wear? I'm really curious since I haven't ever seen a bad one, or even heard of one of these going bad. I may have, but it would have been so long ago I don't remember.

[roger albert]

exactly my thinking tvrla. I've only seen them bad twice, both with bone dry rear housings. Even then they only seemed chewed up by bearing debris. This is really odd.

[shannonnunley]

Originally posted by tvrla


Are you saying that the ring gear is worn?

Yes.

Originally posted by tvrla


Could you post some pictures of this part and the wear? I'm really curious since I haven't ever seen a bad one, or even heard of one of these going bad. I may have, but it would have been so long ago I don't remember.

Yes, but it's a little hard to see. Where the gears aren't contacting and where they do contact, there's noticable difference in the width of the teeth. It's over at the dealership getting some races removed, so it'll be a day or two.

[tvrla]

What do you figure caused the damage?

[shannonnunley]

not sure.... I've never even started it up. The previous owner might have neglected oiling the final drive.