So i had the common clips break off in my rear diff so i replaced the diff with the Detroit Locker Limited Slip Truetrac. my avg mpg was 12.2 now im getting 10.8. how would getting my rear end working properly lower my mpg?

 

just serviced it last week checked plenum repair i did earlier this year, looks clean still. K&N drop in air filter was still spotless. tire pressure is correct. only other thing i have done is removed side steps and replaced two inch springs with three inch springs. with the two inchers i was still getting the 12, would one more inch take 2 mpg away from me?

 

You answered your own question. The rear is working more now that there's a better traction aid. Both rear tires are more likely to turn under power in low traction situations. That will in turn make the engine work harder to turn the wheels.

 

Under normal circumstances, JUST changing the rear shouldn't affect economy quite that much. Wonder if your local gas station is now getting winter blend fuel?

 

Maybe the gears are too tight with the new diff and something needs to be shimmed or adjusted?

 

are you doing more 2 wheel burnouts?

 

ha i wish! i dont get to have any fun in it. i drive it like an 80 year old trying to make it last. smart, but zero fun

 

No bad. Not smart. Drive the thing. Dont abuse it, but use it.

 

what do you mean by replacing 2 inch springs with 3 inch springs? Are you talking about front end lift?

i suppose that by raising the front end you might be catching more air?
you didn't change tires did you? i lost 2 mpg going from an AT tire to an MT tire.

 

correct front end suspension. and that is what im worried about if it is down already ill be at 8 once i put on my new tires. one tire size up and to an AT from just a street tire.