Datz350 Posted August 23, 2012 Share Posted August 23, 2012 Just finished swapping a r180 with 4.11 in my 71 240z. Took it out for a test drive. It was running smooth until I took my foot off the throttle and let it coast. As soon as I let my foot off I hear this strange noise that sounds like it's coming from the right rear wheel. This sound only happens when I let off the throttle and let it coast. Everything looks ok. I'm not sure what the problem could be... Any ideas? Link to comment Share on other sites More sharing options...
BluDestiny Posted August 23, 2012 Share Posted August 23, 2012 Is it like a metal rattling sound? or like the bearings are going out? Also how many mile were on the dif? Did you open it up before you put it in? What fluid are you using? I have the same dif in my 280zx and it had about 100k miles on it ( front diff probably a lot less) I opneed it and there was some sparkle to the old oil but nothing major. Filled it up with some redline and it was fine when I started driving, but after about 10k miles its making a rattling noise WHEN WARM. When it's cold it perfectly fine. Link to comment Share on other sites More sharing options...
78zstyle Posted August 23, 2012 Share Posted August 23, 2012 Same thing happened to me, was my driveshaft bolts. I bet you it is in your case too. Link to comment Share on other sites More sharing options...
Leon Posted August 23, 2012 Share Posted August 23, 2012 Same thing happened to me, was my driveshaft bolts. I bet you it is in your case too. Agreed, driveshaft and half-shaft fasteners would be the first thing to check. Link to comment Share on other sites More sharing options...
Datz350 Posted August 23, 2012 Author Share Posted August 23, 2012 It's a metal sound. Sounds like it comes from the passenger rear wheel side. The diff "looked" good when I got it. I used 75-90 oil. Not sure how many miles. The half-shafts have no play to them. I give them a good tug and they feel solid. I went to "tug" the driveshaft and noticed a bit of play. Is that normal? I was thinking that it may be a wheel bearing as well, seeing that the grinding noise only happens when I have let go of the throttle and am coasting. Any ideas? Link to comment Share on other sites More sharing options...
SUNNY Z Posted August 23, 2012 Share Posted August 23, 2012 I bet you dollars to donuts its just whiny. Mine does this too. whisper quiet under load, then when you take the load off it, it whines. the solution: KEEP YOUR FOOT IN IT 1 Link to comment Share on other sites More sharing options...
Datz350 Posted August 23, 2012 Author Share Posted August 23, 2012 Lol! Trust me, I've been thinking of just biting the proverbial bullet, but it isn't whiny, it's more like grindy.. Link to comment Share on other sites More sharing options...
Datz350 Posted August 28, 2012 Author Share Posted August 28, 2012 Alright, took the driveshaft off. Some oil came out from where the driveshaft and differential connect, not sure if this is normal... Then I noticed the "gear" where the driveshaft connects to the transmission has a bit of play. Also sounds like something is broken inside the "tailshaft" of the transmission. It's a th350. I'm thinking I need a rebuild or swap, right? That loose "gear" in the tailshaft of the transmission seems to be causing the grinding noise. Any one experienced this before? Link to comment Share on other sites More sharing options...
Datz350 Posted August 28, 2012 Author Share Posted August 28, 2012 Well, figured out one of the u-joints on the driveshaft has some trouble spinning freely. Could this cause the grinding noise?? Link to comment Share on other sites More sharing options...
Scarab73 Posted September 13, 2012 Share Posted September 13, 2012 Well, figured out one of the u-joints on the driveshaft has some trouble spinning freely. Could this cause the grinding noise?? Hi, By now, you would have replaced both universals on the drive shaft. So, still have the noise? Link to comment Share on other sites More sharing options...
Datz350 Posted September 18, 2012 Author Share Posted September 18, 2012 Yeah. Figured out it was the front pinion bearing in the differential. Have yet to get it fixed. Any idea at how much I'm looking at? Link to comment Share on other sites More sharing options...
Scarab73 Posted September 18, 2012 Share Posted September 18, 2012 Yeah. Figured out it was the front pinion bearing in the differential. Have yet to get it fixed. Any idea at how much I'm looking at? Hi, Sorry, can't offer any advice labor costs, as I usually do my own wrenching. I have a noise back there as well. So, I'll be visiting the area too. Good Luck! Link to comment Share on other sites More sharing options...
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