Hi guys, well i got my front diff in and all my axles, etc. , etc. and now when i put my 2000 dodge durango in 4wd it lurches really bad. So chrysler told me i had a 3.55 diff in the front so thats what i installed, and a 3.92 in the back which i thought was weird but i assumed they knew what they were talking about since they built the darn thing (no diff ratio on my build sheet for the front thats why i contacted chrysler directly). So i did some research (I think) and my front diff should have been a 3.92. So could that be the problem with my 4wd now the different gear ratios making it lurch like that? It drives nice and smooth and no other problems with it. I really need to figure this out I live in North Dakota and kinda need it (this is what i feel like with this suv lol)

 

Whoever told you the front and rear have different ratios should be shot. Don't try to use 4wd if you do have different ratios or you could blow up your transfercase, diffs, transmission, etc. Jack up each axle and count the number of rotations of the wheels for one rotation of the driveshaft, and that'll be your ratio.

 

thank you thats what i thought so im going to contact chrysler back and have a little talk with the girl that gave me that information.

 

Yes, both ratios should be exactly the same. The drive shafts go at the same speed, so with your setup, the front end is trying to move the rig further per drive shaft turn than the back end, and the D doesn't want to get any longer. Mess with it on the road and you will guaranteed break stuff.

 

+3 You should have asked here first.