Not always.
You set the ring and pinion mesh just like the spur/CB mesh. Only difference is you use shims to remove all excess play. Overshimming kills the bearings. Shimming diffs properly is a trial and error process. Differential outdrive bearings are the culprit on the Savages. they need to be replaced every 1-2 gallons IMO. The newer bulletproof diff design would be a good upgrade if you destroy the stockers. Diff fluid has no impact on the diff issues with the Savage. Just run good automotive high temp axle bearing grease in the cups. That is the best thing to put in the diff cups for longevity. if you race, then experiment with silicone fluids Otherwise they are not worth the hassle. 4 good hours of use and most diff fluids are cooked and no longer do the job.
