I just had a brand new factory rear diff put in and my gas mileage has dropped significantly (from about 240 miles a tank to about 180). Here's what I had Done:

1. Blew up the ring and pinon on my stock 4.30 elocker rear
2. Had a brand new, toyota oem rear put in - identical unit.

Is there some kind of break in period that I need to go through to get rid of some resistance? - Or - could there have been an error with the installation that is causing this. When driving though, everything feels and sounds fine, goes into 4hi/4lo and locks/unlocks perfect. Any ideas?

 

Follow this..It's VERY important!

http://www.4crawler.com/4x4/CheapTri...ml#GearBreakin

Have you broken in your previous sets of gears? I bet that's why you've broken so many.

 

Thanks. The only thing with that is that the rear that broke was the stock elocker that came on the truck new. The unit I put in was the identical, but completly new, rear bought from a dealership. Do you have to break in the gears on a new 4x4 when you take it off the lot? If I was supposed to I might be screwed - I have driven probably 300 miles or so as i normally do (all speeds - 20-30 minute trips).