Guys need some advice .... 2004 2wd RCSB Silvy 5.3 6 lug 8.6 3.90 G80 rear ......DD and tow vehicle .....I make about 3 long tows a year.. car hauler enclosed trailer 7000lb loaded max .Gm rates this trk at 8400 with 3.90 gear ....... some tows can be 20 hours long only stopping for gas ....driving at speed limit or a little higher

I burned up a set of pinion bearings after one summer ( bearings and R&P were newly instlled that spring set up to GM spec pbly on the tight side of spec ...... any one have any advice on how to make that 10b live under these conditions ...I know I could swap in a 14 b rear but really dont want to go to that much work

Being told this common with 10b and heavy towing ?? The rear just gets overheated should use 75/140 sysnthetic oil was using GM sysnthetic 75/90 ...also being told to set up pinion bearing on loose side of GM spec and that will help alot ?? beleive the spec 14-20inch lbs some say 25inch lbs ??
Being told to set up loose at 14-15" .............opinions on that ??

Also going to add a Mag Hytec finned and large capcity diff cover ......holds 4 qts fluid compared to about 2 in stock cover

Opinions Pls .....do you think chaging out the oil to 74/140 and aftermarket cover will keep rear cool enough on these long hauls or is only way to go to 14 b .......I just se alot of trucks pulling car trailers with 8.6 rears dont hear of fialures ..or was my pinion bearing preload just set too tight //

 

i would have to say preload was too tight. i don't see 10 bolts tearing up pinion bearings being common.