Rear Driveshaft Spacer

From Faq

Another way to help cure your rear driveline woe's is to install a spacer between the pinion flange and the driveline. On extended cab and double cab models you can also drop the carrier bearing down using flat washers to help the driveline angle (See the next article). Installing a spacer will push the slip yoke back together after lifting the truck. The other alternative is to get your driveshaft lenghtened which can cost upward of $300-400. There are several advantages to using a spacer. First of all is the cost. I had several made for about $60 - $65 each depending on the thickness. I recommend 5/8" for a typical 2.5" - 3" lift. A 3/4" will work for a typical 4" lift. Second is the spacer saves wear on your entire driveline. By pushing the slip yoke back together you reduce the wobble of the driveshaft. This wobble is what contributes to vibrations, U-joint wear, pinion seal wear, carrier bearing wear, tailshaft seal wear, and slip yoke wear. Third is you get back the lost extension travel that was taken away when you lifted the truck and didn't get the driveshaft extended. There is nothing to keep the driveshaft from simply pulling apart at the slip yoke under extreme extension. A spacer will help! Fourth is the spacers are made from billet aluminum so as long as you don't have a 600 h.p. engine, you're not going to break it. Additionally being that they are aluminum it reduces the reciprocating mass compared to a steel spacer. Fifth is you should be able to return your slip yoke to very near stock setting by a simple bolt on part as opposed to taking the driveline completely out and getting it cut and rewelded with a longer tube. The tapered tube drivelines are especially expensive to have lengthened. Disadvantages are that in extreme short driveline/high angle situations (Such as a Jeep CJ/Wrangler) using a spacer will increase the u-joint angles causing extra stress and potential vibration. Would not recommend for extreme rock crawling, smashing and thrashing, but great for the daily driver/moderate use truck.

Spacer and Bolts

5/8" and 3/4" Side view

Before spacer installation

Slip yoke pulled apart (example of over extension)

5/8" spacer with Grade 10.9 hardware installed

Spacer installed and slip yoke reset to stock (yellow paint marks on slip yoke)

Carrier bearing spaced down 1/2" on both sides