Niva Resource: TC Alignment

Gearbox and transfer-case alignment.

A Niva shouldn't have serious transmission vibrations. If it does that means something's not right, and should be attended to before it does damage.

Vibes are usually be caused by a misaligned transfer-case (see below to fix).

But they can also be caused by softened (or loose) rubber mounts on the gearbox and/or transfer-case; a soft or worn donut; cracks in the floor around the gearbox or transfer-case cross-member mounts; cross-member or front differential nuts not being properly tight; worn (or un-greased) universal or CV joints; worn (or un-greased) slip-joints on the drive-shafts; or out of balance drive-shafts (can be from dried on mud). Here's troubleshooting guide to vibrations.

Hoodoo's Transfer-case Alignment Method/s (quick-ish and easy):

To ensure correct alignment, once everything in place, and with mounting bolts slightly slack, start engine. With transfer-case in neutral (ie the High-Low gearstick sitting in between High and Low), and the difflock OFF, engage second gear and let idle. Transfer-case levers should not wobble, but be stationary. Adjust transfer-case from underneath to achieve this.
The other method is to run the engine to about 3500rpm so that everything finds its own place. If all's well the transfer-case levers in the cabin to be still (ie not vibrating or shaking) and you can bolt things back up and enjoy driving a vibe-free Niva. This only works properly if the spacer shims are correct.

Note: if the TC adjusting shims/spacers (3) are wrong (eg because the engine/gearbox mounts have sagged, etc) you'll need to add/remove some to get the TC at the correct height for proper alignment (see Mirror Method below).

The Mirror Method

Used to determine the correct spacer height

"Essentially, you need to affix a mirror to the base of the transfer case. You then need to loosen the nuts holding the transmission and transfer case mounts to the car. Bring them down to the end of the studs but leave them attached to the vehicle. You then need to raise the vehicle if possible and reflect a focused beam of light onto the mirror. You can then watch the reflected image of the light when it hits the ground. At this point you can get your assistant to bring the vehicle to speed (either with the t-case in neutral or the drive-shafts disconnected), you will want to "travel" at your most common road-speed. While watching the reflected image of the light, you can adjust the height of the transmission and transfer case until the light stops vibrating on the ground. At this point you can add spacers as needed to correct driveline angle so that minimum vibration is transmitted when the nuts are fully tightened." - Sean Huffman

Ahma's Wire TC Alignment Method (also simple and looks easy to get things near perfect):