adjusting driveshaft, pinion angle

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
4,180
1,289
113
Larsen, Wisconsin
Holy crap I never knew there was such crazyness to making sure my driveshaft was at the proper angle. I've just left the truck stock height and let it be.
 

gmduramax

Shits broke
Jun 12, 2008
4,077
250
83
Nor cal
1304eca93c5402ea97b83daccde9e39b.jpg


So this is what I have now, no preload on the caltracs. Is the upward angle at the transfer case okay? I was thinking I could lower my transmission to get 2* angle at the transfer case and I can add a little preload on the caltracs.


Sent from my iPhone using Tapatalk
 

juddski88

Freedom Diesel
Jul 1, 2008
4,656
120
63
Chesterfield, Mass.
Why would you drive around with preload on the caltracs? That would just amplify any road noise or geartrain noise throughout the chassis, and ride stiff as hell. With those angles you just took, you have vibrations still? How far forward is the slip yoke into the tcase? Ive run a -3deg total like you drew out there before in a lifted truck and have not had any vibration issues with everything else in the system in good condition. On a hard hit to the rear end, though, without setting everything up for a run like at the track, I'd expect to see the pinion roll up 5-7 degrees
 

gmduramax

Shits broke
Jun 12, 2008
4,077
250
83
Nor cal
Why would you drive around with preload on the caltracs? That would just amplify any road noise or geartrain noise throughout the chassis, and ride stiff as hell. With those angles you just took, you have vibrations still? How far forward is the slip yoke into the tcase? Ive run a -3deg total like you drew out there before in a lifted truck and have not had any vibration issues with everything else in the system in good condition. On a hard hit to the rear end, though, without setting everything up for a run like at the track, I'd expect to see the pinion roll up 5-7 degrees

I drive around with my caltracs how I race it. Incase I drive to Mexico one night

I haven’t driven it yet I just wasn’t sure if I could have a upward angle at the transfer case.
 

juddski88

Freedom Diesel
Jul 1, 2008
4,656
120
63
Chesterfield, Mass.
Under increasing load, the 1 deg angle will only get slightly better, so that's good, but as the rear suspension unloads it will likely go to 0, which very well could cause a vibration. At the pinion, like stated above in this thread, you want to avoid zeroing the u-joint angle also, so knowing how much it rolls under your applied load is important. I'm assuming that you already checked this too, but make sure the axle perches/shims/center pin are all lined up correctly too. Just 3/8 of a inch out on one side will cause vibrations.
 

gmduramax

Shits broke
Jun 12, 2008
4,077
250
83
Nor cal
Ok good to know. I might take a 1/8” out of my transmission mount to put a hair more angle but I should probably drive it first. My driveshaft is now 3/4” away from the crossmember so that’ll be cut out before I drive it. And I’m probably only going to put a hair preload on the caltracs.
 

OregonDMAX

NOT IN OREGON, NO DURAMAX
Apr 28, 2013
3,964
8
38
36
Goodyear, AZ
I'm lower than that and don't have any issues and adjusted nothing as far as driveshaft angles. Are you sure your vibration isnt from an out of balance driveline or something else being amplified from the angle change.
 

gmduramax

Shits broke
Jun 12, 2008
4,077
250
83
Nor cal
I'm lower than that and don't have any issues and adjusted nothing as far as driveshaft angles. Are you sure your vibration isnt from an out of balance driveline or something else being amplified from the angle change.

I think the fenders on the NBS trucks are higher. My frames cut and I’m going to cut the crossmember out that goes over the driveshaft.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,691
5,847
113
Phoenix Az
1304eca93c5402ea97b83daccde9e39b.jpg


So this is what I have now, no preload on the caltracs. Is the upward angle at the transfer case okay? I was thinking I could lower my transmission to get 2* angle at the transfer case and I can add a little preload on the caltracs.


Sent from my iPhone using Tapatalk



This with the 6* shim or 3*?