I have an 02 lb7 that i just had the allison and transfer case rebuilt at 259,000 miles and the u-joints were replaced before the rebuild. Now i got the truck back and noticed it was leaking and it turns out the rear transfer case half was cracked.... got it replaced under warranty and the tranny shop called today saying that the tailhousing of the allison was cracked... i was wondering if there is anything internal that can be done that might cause a vibration between those two parts?

 

abuse can cause the tail housing to crack, it does happen on higher mileage trucks... you can buy a new tail housing and a support bracket that helps, or you can spend big bucks and buy a billet tailhousing