17brpeterson1 Posted October 17, 2021 Share Posted October 17, 2021 So, I am at my whits end with making a r-200 diff work in my 1978 280z with a 5-speed. When I first bought the car, it had a really loud noise coming from the diff. This is no slight whine either, it is OVERBEARING. The car is straight piped right now and it is still overbearing. Later on I tore into it and found nothing really wrong at all. Installed an M-factory helical diff and rebuilt the whole unit with all new bearings. I closely followed the factory service manual. Almost the same exact noise occurred with the same volume. I gave up and had a shop tear in and rebuild the diff, install and it was exactly the same. Bought a whole unit off ebay with the same ratio, checked backlash, everything looked ok. Same story, unbearable noise. The car has the factory mounts but with urethane bushings. Everything else looked and felt good, u-joints, mounts, wheel bearings. The noise I am hearing is from the differential as it changes under load, being the loudest when the car is coasting. I'm not sure where to go next, ive already wasted 2k trying to have a functioning differential. Any and all tips or suggestions would be greatly appreciated at this point. Link to comment Share on other sites More sharing options...
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