I plan on swapping from the 3.55 gears on my 8.8 axle to 4.10s. Theres a guy who has a whole used differential assembly with all bearings pressed on (pinion included) and with 4.10 gears. Its also a LS. My question is can i just take out my existing assembly and drop that one in? Or do i still need to make all those measurements (like backlash) when doing a complete rebuild? Should i do it myself or just have it done at a shop? I want the whole assembly b/c its a LS and i currently have an open differential

 

Yup you always need to re-measure backlash and bearing pre-load when re gearing because whenever you change a ring gear, you also need a new pinion gear that goes for it. If you already have all the parts, it will be a little cheaper to have a shop do it cause you will just be paying labor.

 

Technically you would prob be fine just torquing pinion correctly and make sure your gears mesh properly. You'd be changing entire carrier, not just gears. So you shouldn't have to shim anything. But it's definitely a good idea to.

 

It must be re-shimmed and re torqued. I'm not sure what the last post ment saying you don't have to re shim the carrier, that is the part that gets shimmed. No 2 axle housings are exactly alike especially worn used ones so you need to set set them up. You also need a new crush bearing for the pinion as well as shim for the pinion depth. The pinion and ring gear are a matched set especially if they are used so they must be used together. If either one is no good you need a new set of gears. Make sure all the bearings are good especially the pinion bearings. They are the most likely to be bad. You can replace all bearings separately if you need to.or order a new kit. You can do the job yourself if you are mechanically inclined. Just find a good step by step instruction set. There are good videos online to help. You need a dial indicator, ( harbor freight about $10 ), an inch pound torque wrench, a foot pound torque wrench, a big ***** breaker bar, and something to hold the pinion yoke with. Some people fabricate one from some flat steel and drill holes to bolt on. I used a big pipe wrench. You will also need access to a press for the pinion bearing when adding the shim. I recommend replacing this one, its often damaged when being removed and its cheap insurance anyway. Most machine or rear end shops will press the bearing for you.