Front Driveshaft Angles

[jdeere3010]

With 4" of lift, is the front driveshaft/pinion angles a concern? My driveshaft has the cv joint on the transfer case end and I will need to grind it slightly to prevent a very very slight bind. What is the best way to change this? How much does a transfer case drop help this?

[GreaseDog]

driveline angles are always (or should be) a concern. however, more importantly than drivetrain geometry is steering geometry. it effects handling, tire wear, and can effect fuel economy.

once you get the steering correct, then worry about driveline. you can grind the CV for clearance. the transfer case drop will actually make your front angles worse.

[chevybig10]

Grease is right.

You have a driveline with what we call a "3R" style ujoint.

the pinion yoke welded into the tube has square knobs sticking out towards the cv. Grind them right round. then the h block (metal with 2 ujoints in it) has square knobs. Grind those off to make then round. then your flange yoke has square knobs facing inwards to the cv. Grind them off right good and round.

this will make it run at high angle.

If it is too short now, you need a longer spline welded into the tube....or longer tube welded in and keep your spline shaft and cv.

The front shaft should be able now to turn at a much higher angle....if it clunks or makes contact anywhere grind that spot.

If you run even more angle that it can't take it will snap the pin off the pinion yoke and fly out. that's all you're going to get angle wise until you pay a fortune for a different custom built driveshaft. But with onnly 4 inches you will be just fine grinding it.

[chevybig10]

Correction

Greasedog is mostly right. If it binds and tears out and flails around you will be very very very sorry that 15 ols of steel is flailing and tearing out anything close like wires and lines and your body. It counts just as much as your steering.

If it flails and yanks your diff yoke sideways on your diff you can get some fast front diff damage too.

Do not discount your driveline angles.

[GreaseDog]

there's no mostly right...

the FIRST priority is to make sure the truck can be controlled properly on the road, which takes in your steering components, alignment, geometry, and front suspension, while taking in the brakes.

you do not need 4wd to drive the truck safely on the road. if it binds, breaks, and you're going fast enough for it to make its way through the trans and transfer case and to your body, you're doing something VERY wrong. set the truck up properly to go down the road, THEN worry about what happens when you pull the lever and lock the hubs. in most cases under 6" of lift you can get by with grinding the CV as posted above. if you have the truck setup to flex more than most suspensions do, its time to step up to a bigger CV to allow for more angle.

[chevybig10]

I guess you're right, my mistake. I was thinking of the trucks that keep the driveshaft turning at all times. In that case a truck will rip itself to pieces, as they only lock the hubs. In our case the driveshaft does not move till you engage the transfer case so it would not rip itself out.