Is there something wrong with it (other than being an open diff)?
Is it possible to rebuild the differential in a 1999, non-torsen. If so, any recommendations? Does Rogue do this? I've called him 3 times today with different questions (he's working on my '99 now), and I fear I'm becoming an annoyance, so thought I'd ask here instead.
Thanks,
-Tim
Is there something wrong with it (other than being an open diff)?
Trying to chase down the rattle and excess slop in the drive train I asked about in a previous post (http://forums.dfwmiata.com/showthread.php?t=10766). Rogue looked at the tranny, and there is no excess slop in the transmission, and the propeller shaft seems solid, so it looks like the play and noise is either in the differential or stub shafts.
The slop is most pronounced when I'm creeping along at low speed in stop'n'go traffic. It'll start to buck a little sometimes bouncing with what sounds like bad u-joints, with a pronounced 'clunk'. However the propeller shaft seems fine when you twist it by hand.
-Tim
Last edited by scorn001; 12-10-2007 at 02:27 PM.
If it is the diff, it should be howling like crazy. About the only thing that fails in a diff is the pinion bearing. You should be able to feel that by rotating the driveshaft. What you previously described would be a rattle.
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I understand, and isn't howling, at least not loud enough that it is obvious to me at speed, and there is no metal that is evident in the differential oil or on the plug. There is a noise however back there that Rogue heard, but couldn't quite identify, and he did feel the slop I referred to, and commented that the transmission seems fine, so he felt like it was either a stubshaft, or something happening in the diff.
-Tim
Based upon the bucking you are experiencing, you need to replace your motor mounts and possibly your diff mounts.
Most factory motor mounts are gone after 60K miles. I replaced the motor mounts in my '96 miata at 100K. One was broken in half and the other was nearly in half.
+1 on the motor and diff mounts idea. If you had a chunk missing out of the ring or pinion gears you'd really now about it, because usually one chunk leads to about 5 or 6 others. A really easy solution to your problem is to turn the radio up :]
Isnt a some bucking normal? How bad is it really? If I cruise through a parking lot or in stop and go traffic the car can buck a little bit if I am not careful with the gas.
It definitely would be if your on and off the gas a lot. If there is no whining or "clunking" sounds I'd just say its motor and diff mounts like other people have stated. Even if it was your diff going out, I'd just get another one from mazda heaven and not even bothering rebuilding it, especially since its an open diff.
Yes, I wouldn't be giving it a second thought if it weren't for clunking sound I'm getting when it bucks. How loud is too loud for a miata? I don't know. I know that if I heard this sound coming from my truck, I'd be looking at the u-joints.
I'm at Collins & Glenville in Richardson all day if someone cares to have a listen.
Rogue does believe that something is going on with the rear-end, but its not severe enough for it to be obvious what precisely is wrong. I'm going to keep driving it expecting that at some point it will get worse, and be easier to diagnose at that point.
The invitation is open however to anyone who wants to have a listen. I get 'er back from Rogue tomorrow morning.
-Tim
I think I've seen parts from them via this website, but I'm not positive.
http://www.urgntx.com/
edit -
If you click "Members", they are listed there.
http://www.urgntx.com/map.html
I don't like the ~$500 premium over the standard open dif. The open seems to be working fine for me, if I were tracking it, I'd probably have a different opinion. I actually went a long time thinking I had the VLSD because I thought I had the Sport package, and both wheels always seem to spin at the same time. Then I found out I only have the Touring package, which was a relief when I looked at the prices of differentials.
-Tim