Im getting ready to do my sas and chevy rear swap and im trying to figure out if I need to have my driveshaft lengthened. I read on the pirate FAQ that with just the springs (about 3" of lift) you do not need the driveahaft extended. Im planning on running about 6-7 inches of lift.

So at what point do you need to have the driveshaft extended?

Oh its a 91 4Runner

 

i didnt extend mine at first and had no problem. i have since extended it by 3inches when i bent it.

 

ok so I guess I should leave some cash in the budget just incase then.

 

what springs will you be running up front?

 

There is such a limited amount of slip in the shaft you will probably need to change the length. It also depends on how large of tires you are going to run. The larger the tires the more that you have to move the axle back.

 

I had no issues with driveshaft length on my '85 with a 3.5"-4" lift. This is assuming you are leaving the axle in the same location as stock (i.e. not moving it back or anything). On the other hand, the stock front shaft was too short and needed to be lengthened.

 

I will be running Toyota rears up front with 37" tires, maybe 38s. Im planning on moving the axle back an inch or two. I dont want to go too far back since my front will be moved forward 2 inches and I want to keep my turning radius as small as possible.

 

Moving the rear axle back is a little harder than moving the front one forward. Why? Wheel well is not as large. So plan on some major cutting if you do so on a 4Runner and also, cutting the rear fenders means cutting into the inner body panels, so it is a lot more work to clean up.

 

Hmmm. I was planning on just getting rid of the rear bumper that runs all the way to the fenderwell. Maybe trimming whatever I need to so I can get the tire to stuff as much as possible. Ill have to take some time and look into this once I get the springs under the truck. So with the axle in the stock location I could possibly run a stock length driveshaft?

 

There are a lot of factors in the equation. If you are thinking about going 6-7inches of lift I would have to assume that you are running 37" tires. 37" means that you are going to need to trim and most of the trimming has to go towards the rear because of the doors; which means that the axle will be moved back. Also you need to study the travel path of the axle, currently your axle moves strait up and down for the most part. with leaves your axle will move back as it moves up and vice versa. Either way if you have to change the length of the shaft it shouldn't cost more than $100

 

Yes, look twice before cutting on the rear of the 4Runner body. At least if it is a vehicle you want to keep sealed up on the inside.

All depends on how much droop you get with the springs, but usually the rear shaft is fine for that lift. Reason being the rear spring shackles cause the rear axle to swing forward, towards the transfer case, as the suspension droops, limiting the amount of shaft extension needed. I ran essentially a stock driveshaft (actually shortened for dual cases) in back with 4"+ lift and it was fine.

 

Thanks for all the help guys. Im going to do some more research on cutting up the rear fenders and inside panels, maybe take the carpet and side panels off. I guess I wont know for sure what i'll end up doing til I get everything under the truck.

Thanks again.

 

I just realized it is a 91 runner it would help if I could read. I thought you were talking about a 3rd gen runner which is pretty easy to cut towards the rear.