I just replaced the ring gear and pinion and all the bearings in my 2000 chevy silverado with an 8.6 rear end and i am leakin fluid around the pinion seal and it is new do i have to put silicone around the splines to seal it

If you have an 8.6" ring you should have a 10 bolt axel. With this axel you don't torque the pinion nut. This style axel has a crush collar. Down below I forwarded the preload torque specs. If you do have a 12 bolt axel, the ring gear does get torqued but the ring gear will not be 8.6" Please write back if you need anything thing else. Pinion Preload New: 14 to 19 in-lbs Pinion Preload Reused: 6 to 8 in-lbs

If you are definitely sure it is coming from the rear end you have to remove the rear end cover. You will see the condition of the fluid check the fluid while that is being done. You will have a bird's eye view of the condition of the ring and pinion gears and the pinion bearings. The rumble from the rear end is usually a bad pinion bearing.

If you're not sure it is the rear, another often overlooked problem is the rear universal joint on the drive shaft. You have to remove the drive shaft to check the pinion bearing so you'll find the "U" joint is bad right then and there. If the joint is bad, don't cheese out, get both of them replaced.

Replacing gears and/or bearings in a differental is not an easy project. You'll need a press. The positioning of the gears requires a great deal of precision. Shims are used to acheve the correct setting. Preload setting on the pinion bearings is critical. I would recommend leaving this one to the experts.

probably a different manufacturer as long as they fit correctly they should work

realistically?? take the rear end apart , you can purchase the bearings and seals as a kit, that will include carrier bearings pinion bearings , crush spacer and seals, clean the housing carefully, you will have to set the backlash on the carrier, adn also the preload on the pinion

Sounds like the original wear pattern of the ring and pinion was disturbed when the pinion was tightened too much. Once a wear pattern is set in the gears you can't really change it. It might be the ring and pinion wearing that you are hearing and not a bearing at all. It's not the worst thing in the world but will cause the ring and pinion to wear improperly and is annoying. Differential work needs to be done by someone that really knows their stuff to avoid these little problems.

Check rear-end fluid level and play in rear pinion gear.
Check universal joints for play. If play is in pinion gear change rear end fluid and add a full bottle of LUCAS oil stabilizer, will quiet rear end noise.

you can count the teeth on the ring gear and divide that # by the tooth count on the pinion. An example is: ring gear 100, pinion 10 ...100divided by 10 is 10, expressed as 10 to one. (fake #) your diff is likely a 3 series such as 3.23 to 1. or a four series such as 4.11 to 1. If you have four wheel drive it is critical to match exactly. if not you can get better performance by changing ratio to something that better fits your needs. 4 series pull loads well, 3 series are better on fuel.(depending upon terrain)

this means the ring and pinion gear are worn, but when u do the gears u will need to also replace all the bearings as well.

Differential bearing caps 70-85 ft lb
Ring gear bolts 70-85 ft lb
Pinion bearing preload if using original bearings 8-14 lb-in, if installing new bearings 16-28 lb-in