R200: How much slop is too much?

[FastWoman]

Hi all,

So I'm looking at my rear axle again, figuring out how to tighten it up. (It gets a bit bucky and jiggly sometimes.) I had previously noted that my passenger side half-shaft had a lot of play in it, so I knew I had some work to do there.

Today I jacked up one wheel, left the other on the ground, put the transmission in gear, and turned the lifted wheel back and forth to figure out where I had play. The outer U-joint on the passenger side is pretty well shot, as I can see it rocking and wobbling around. The rest of the half-shaft joints, both left and right, look OK. They might be worn, but they're not a major source of play. Unfortunately the wobbly U-joint isn't the whole story.

When I rotate the wheel back and forth, I get about 1.5" of rotation along the circumference of the tire. Approx. 0.5" of that is due to the U-joint. The remainder of the slop (1") seems to be within the differential itself. So is that amount of differential slop within normal limits, or do I need to consider rebuilding (or buying a used R200 in good shape)? As some of you might recall, this is the same differential that had filings in the oil when I changed it out. I've recently obtained service records from the dealership that did 99% of the service on the vehicle, and the last differential oil change would have apparently been about 70,000 miles and 18 years ago.

Any advice is greatly appreciated. Thanks, guys!

Peace,

Sarah

[FastWoman]

So this was a dumb question?

Jmortensen was kind enough to provide a bit of useful info for me in another thread, but with more information from me (in this thread, following a more careful examination of my drive train), perhaps someone would have a better answer for me?

I don't have a limited slip differential, BTW. At least there aren't any heat sink fins on the case. Just a plain R200.

If anyone has any notion of whether this amount of play is excessive, I'd very much appreciate the insights.

Thanks!

Sarah

[70 Cam Guy]

It's not a dumb question, but it is hard to answer "feel" and "noise" type questions. Lots of variables combined with differences in perception.

An inch at the circumference of the tire doesn't seem unheard of to me. Lots of tolerances are stacking when you rotate the tire back and forth depending on what stops your rotation. Are you waiting for the pinion to turn or waiting for the drive shaft to stop the rotation? You're really only seeing 4-5 degrees of rotation. You have the u-joints on both sides plus the backlash in the gears. Also depending on how you're doing this, you're taking up slack in your driveline as well. I also would wager that you're seeing more slop from that u-joint than you might think. You get a lot more torque turning the tire than twisting on a half shaft

If I were curious about the play in my diff, I would put the car on the lift or jack stands and get myself under the car. I spent a good amount of time under it yesterday, and if I recall correctly, there is enough room to reach in and grab the diff flanges. I would hold one flange and try to rotate the other. Being under the car I would be able to see the pinion flange move, and feel what the diff actually feels like.

I glanced at the other thread about the noise. It's common for gears to make noise on decel. Does the noise persist when you coast in neutral (on the freeway or wherever you hear the noise)? If the noise goes away in neutral, I would be looking at the transmission before the diff.

If I were convinced my diff was on its way out, I would start watching Craigslist, classifieds, or the local wrecking yards for another R200. Everything I've seen tells me the R200 takes a lot of abuse so I wouldn't be too concerned about buying a used one

[FastWoman]

Thanks, Andy.

All of what I've described is under only mild torque on the wheel. I have the car in gear and rotate the jacked up wheel from extent to extent, until it locks up. As I rotate the wheel back and forth, I don't see any movement in my drive shaft (which would require slop in the transmission). The "inch" of movement I'm describing is from the drive shaft flange and one of the half shaft flanges being held stationary and the other half shaft flange rotating approx 5 deg under very mild torque (until I hear/feel the gears go "clunk"). The half inch (perhaps 2.5 deg) of rotation is from one of the U-joints that's well beyond shot. I'm probably not applying enough torque to reveal slop elsewhere, although I'm sure it exists.

I honestly don't know whether the soft whine is there in neutral. I'll find out on my next trip out. Thanks for the tip! I think I'd find out a lot about the transmission if I could only get the oil drain plugs undone. I think they must be super-glued in place. Oof!

[jmortensen]

Pull the cover, measure the backlash the right way, with a magnetic base dial indicator measuring on the ring gear. Then you don't have to wonder about it.

[geokr]

Pull the cover, measure the backlash the right way, with a magnetic base dial indicator measuring on the ring gear. Then you don't have to wonder about it.

This sounds a lot like my R200, too. Can the backlash be taken out with adjustments or is the wear unadjustable?

[jmortensen]

This sounds a lot like my R200, too. Can the backlash be taken out with adjustments or is the wear unadjustable?

It's probably not a backlash problem at all. Checking it from the pinion is VERY hard to do accurately. If the backlash is really opened up a lot, the ring and pinion probably have a LOT of wear, and the diff is most likely junk. I have to speculate here, because I haven't ever seen one that wore out in such a way as to really open up the backlash either in person or on one of these forums. It's a red herring. Plenty of people think that their backlash is really bad because they have a clunk. I suppose it is possible, but it has not been the culprit in any case that I've ever seen.

[jmortensen]

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=623

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=5645

[70 Cam Guy]

It's probably not a backlash problem at all. Checking it from the pinion is VERY hard to do accurately. If the backlash is really opened up a lot, the ring and pinion probably have a LOT of wear, and the diff is most likely junk. I have to speculate here, because I haven't ever seen one that wore out in such a way as to really open up the backlash either in person or on one of these forums. It's a red herring. Plenty of people think that their backlash is really bad because they have a clunk. I suppose it is possible, but it has not been the culprit in any case that I've ever seen.

I have to agree. In my time hanging out at my friend's shop, it takes a serious amount of abuse to harm the R200. They are running 250-350 (dyno'ed) whp in their SR powered drift cars. I have seen 2 wasted but it was serious carnage when the spiders exploded and punched a hole in the cover. They were both welded diffs.

Jon knows differentials, that is his business. I would trust his opinion. A mag base and a dial indicator are good investments if you really want to inspect your gears. Not to say worn gears aren't a possibility but measuring will certainly answer your question.

Does your car have a lot of miles?

[jmortensen]

Jon knows differentials, that is his business. I would trust his opinion. A mag base and a dial indicator are good investments if you really want to inspect your gears. Not to say worn gears aren't a possibility but measuring will certainly answer your question.

Thanks for the vote of confidence. I am starting a business that sells diff parts with my brother-in-law Mat www.m2differentials.com (nothing for Z's as of yet and the site needs a lot of work). For the last six years I've sold doggie doors through my other business www.thepetdoorstore.com, so keep that in mind too. And I'm not building or repairing diffs this time around, just selling the parts. In my favor, I've built ~10 differentials (Toyota 8" and Ford 9" mostly) and completely disassembled and reassembled the R200, so I think I have a clue as to what is going on.

I do like the suggestion your suggestion that they check it themselves. Eliminates all doubt one way or the other and doesn't rely on the expert opinion of someone trying to diagnose a noise or perceived slop through a post on a car forum.

[geokr]

Does your car have a lot of miles?

Yes it does - this differential is approaching 300K miles so I've gotten my money's worth out of it. Still, if it can be adjusted or rebuilt for less than a replacement I would prefer to keep the original.

[70 Cam Guy]

Yes it does - this differential is approaching 300K miles so I've gotten my money's worth out of it. Still, if it can be adjusted or rebuilt for less than a replacement I would prefer to keep the original.

:eek: I don't know what kind of wear you'll see with that kind of mileage. OE gears are typically very resistant to wear exceeding a light polishing. If I were sure the noise wasn't coming from another source (wheel bearings, transmission, simple tire noise), I would bet on carrier bearings or pinion bearing before condemning the gear set.

Sure thing Jon, I'll remember you know how to build a Toyota 3rd member when I need to do my Toyota elockers

You might like this site.... http://gearinstalls.com/ ...I've read a LOT on the elockers there. I might have to steal his design for his tools