[Blue70SS]

Originally Posted by PfadtRacing

Hey folks. As has been mentioned earlier in the thread a few times, our differential bushings don't create noise that wasn't already there. One thing the factory bushings do well is isolate noise from the differential, and when you move to a harder bushing material for performance reasons you run the risk of increasing noise transmission into the cabin. An instance we have seen of this came with a husband and wife who each purchased Camaros about the same time and did the same differential bushing install, one saw an increase in cabin noise and one was whisper quiet.

Sometimes when moving to a set of aftermarket gears the noise can be lessened due to the amount of attention to detail that can be paid by the tech setting up the differential. There has also been some success reducing noise by changing the stock differential fluid and going to the OEM Fluid for limited slip differentials, or perhaps an aftermarket fluid that's slightly heavier in weight. When troubleshooting noisy differentials in Corvettes and Camaros typically the dealership will start with their differential fluid with the limited slip modifier, and this has proven to take care of quite a few noisy differential issues.

We have experimented with different durometer polyurethane for the differential bushings and it can be a "catch 22" scenario. The ideal product will be be extremely stiff whilst transmitting absolutely zero road noise and gear whine. Unfortunately, there is no magical solution as a bushing that is soft enough to transmit no noise will also deflect more, and therefor is not much of an "upgrade" to begin with. Our differential bushing kit only currently ships in a street version which during our testing we found to have the best combination of performance gain and smallest chance of increasing NVH. Ultimately we find that most bushing kits are being installed into folks looking for a serious performance gain, and that's certainly realized with these bushing kits.

Thanks for the feedback. The husband/wife owners are Lingenfelter owners in New Mexico. The husband had the noise problem with OEM gears, while the wife that had LPE 3.70 gears. They have since both gone to Ford 9" rearends. However, the early changes from "strip" to "street" bushings did help them alot.