When upgrading the gears in the rear end of a 2008 4x4 from 3.73 gears to 4.56, is it 100% necessary to change the front axle gears also?

 

If you remove the front drive shaft, I don't believe so, but let someone else verify what I just said before trying it.

 

If you ever want to use 4wd, it's necessary. Pull the front driveshaft if you don't regear the front.

 

I've been driving for almost two years with mis-matched gears. Zero issues what-so-ever from doing this. BUT, as stated...don't put it in 4WD. You don't have to remove the front drive shaft either...I never did. They are recommending this for insurance reasons. If you never put it in 4WD, there's no mechanical reason to remove the drive shaft...I simply pulled the cannon plug off the back side of the switch to ensure it didn't accidentally get turned on.

Funny you asked this question...I'm ordering the stuff to update my front gears this week. Just moved to where I'll have to contend with mother nature this winter and want her working.

 

what would happen if i use 4wd with mismatched gears? just curious

 

Whatever is the weakest link inside the transfer case would snap...but there would be one and it wouldn't be pretty or cheap. Only way, and I do mean the only way you might get lucky is if you were in A LOT of slop and there were PLENTY of slip between the slop and the tires for them to turn over. I've heard of serious mud boggers running mixed gears for those mud pits, but I ain't gonna try it.

 

Basically, with 2 different ratios, the front tires are turning at a different speed from the rear. That means something has to break if 4wd gets engaged on a hard surface. Mud-Boggers, as in race trucks only, will run a faster ratio up front to keep the nose of the truck up by turning the tires faster. But it doesn't work on anything other than really slick mud. The boggers roll to the pit in 2wd and after they're in the pit they shift to 4wd.

 

With an 04+ that uses IWE's instead of the internal diff lock, I'd pull the front driveshaft to be completely safe.

 

What's IWE?

 

I did that wasn't about to take the driveshaft out

 

didn't see this not sure thought he was 97-03

 

Yes, mine is an '02. That's why I asked George what an IWE is...I've never heard that term.

 

IWE = Integrated Wheel End

 

On the 97-03 the differential has an internal disconnect and solid hubs. On the 04+ it uses IWE's which are essentially vacuum locking hubs. Vacuum unlocks them.