zgeezer Posted September 9, 2005 Share Posted September 9, 2005 Two years ago, I located a 3:36 R200, bought it, opened it up, "cleaned" it up with degreaser and a h20 hose, air dried it with hair dryer, sprayed a can of WD40 into it and then buttoned it up. Two months ago or so I scored an clsd from '89 Turbo. Glee, Joy, and Great Happiness. Opened up the R200 and it was filled (and I mean FILLED) with rust the consistancy of a stale french baguet. Dismantled the R200, cleaned out the rust, purchased all new bearings and delivered it all in a box along with the clsd carrier to a local differential guru. This guy never worked on an R200, but had a reputation of being the man to set up you Ford/Chevrolet rear ends. Three weeks and a lot of $ later he delivers a clean 3:31 clsd R200. However, this thing is tight, really really tight. It can be turned only with a six inch bar on the pinion. When it turns I can feel through the bar a drag and then a release and then another drag that feels as if it matches up to the meshing of gear teeth. I pulled the cover, drained the gear lube, painted several ring gear teeth on each quadrant and then turned the ring gear one rotation. The pattern in the yellow "paint" I used looks consistent in all quadrants and is a "smear" pretty much in the middle of each tooth. I've never felt a rear end this tight, but the guru assures me that all it needs is a few miles on it to loosen up. I think he screwed up the assembly in some manner. Does anyone here have any insight as to what exactly might be causing the problem. Any comments would be greatly appreciated before I take it apart again. g Quote Link to comment Share on other sites More sharing options...
JMortensen Posted September 9, 2005 Share Posted September 9, 2005 Couple of things to look for. One is the backlash. Did you check that when you had the cover off? Should be somewhere in the .005 to .008 range. The other thing is the pinion seal. If the pinion seal doesn't get seated all the way down the pinion flange can hit it and cause a lot of drag. Had a problem with that one myself. Last thing would be the pinion bearing preload. If the guy who rebuilt it reshimmed the pinion preload he may have screwed it up somehow, like maybe he didn't put enough shims in. Usually if you're doing bearings you don't need to mess with the preload, but some people do. FWIW, I took my first diff to a normal good ol boys American gear shop and they f'ed it up 3 times. There isn't that much to it, and I'm still not sure how they managed to screw it up so bad, but they did. There is NO reason why you should need any sort of lever to turn the pinion. If that's the case, something is WRONG. Take it back and demand the guy fix it right. Quote Link to comment Share on other sites More sharing options...
johnc Posted September 9, 2005 Share Posted September 9, 2005 http://www.gearedbyunitrax.com/main.html They've rebuilt countless R160s, R180s, R190s, and R200s. Lots of them from me. They have an old guy in back named Carl that knows the Hitachi diffs well and he's trained a couple other guys there too. Quote Link to comment Share on other sites More sharing options...
zgeezer Posted September 10, 2005 Author Share Posted September 10, 2005 Thanks a lot folks for the comments. I think I'll call Carl this weekend. That shop is not too far from me. g Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted September 10, 2005 Share Posted September 10, 2005 the spacer between the pinion bearings IS NOT a crush sleave.the pinion bearing preload is set by shims.if you roll out the diff try spinning the pinion gear by hand .find somebody that knows these diffs.if you fix it before it is run you wont have many damaged parts.i build rear ends at work.if the diff carrier(lsd part) was swapped the pinion gear and bearings didnt have to be messed with.but you had rust parts.the shim the sets the preload might be missing know.if you store a diff leave old oil and cover on it. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted September 10, 2005 Share Posted September 10, 2005 Good point Randy. I had a pretty well respected Z guy tell me that the Z had a crush sleeve in it. In fact he was SURE that it was a crush sleeve. As Randy says the shims between the two cup and cone bearings sets the preload. If this guy tried to set it by crushing the spacer between the pilot bearing and the cup and cone bearings it's gonna be frozen up big time. As I said in my previous post, if they were just replacing bearings the pinion shims that came out would probably be correct for the new bearings as well. Quote Link to comment Share on other sites More sharing options...
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