I have a new d100 project with a 318/727. When I got the car the gauges were out of the car and the speedo needle was broken. Last week I bought a new, nice gauge cluster and was told that everything worked.
Once I installed the gauges, the speedo bounced and made popping noises so I replaced the cable with a new one from eBay.
After installing the new cable into my new cluster the speedo still popped and the needle still bounced. After about 2 minutes of driving that needle broke off as well.
So that's two gauge sets and two speedo cables both resulting in broken speedo needles.
Anyone have any ideas? Could it be the speedo gear in the trans? Truck has 3.91's and I have no way of knowing what's original or not. Any help is greatly appreciated!