1996 Chevy Corvette C4 Project - Differential Equation

Next, the gears are maneuvered into place in the carrier.

Wilhelm then installs a washer on the gears using a special task-specific tool.

With that done, the finished carrier is ready to install in the differential.

The next step involves bolting the diff housing to a stand in preparation for the gear-setup process.

Zip uses special setup bearings that are machined so that they can be slipped--rather than pressed--on and off, eliminating the potential for damage.

Once the setup is done, the bearings and races are swapped out for new ones, and everything gets checked one final time.

Wilhelm places shims on either side of the carrier to achieve the desired backlash reading.

The ring gear is then "painted" with a pigment-based grease. When the ring gear and pinion mesh, the grease pattern left behind indicates whether the pinion has been set at the proper depth. A pinion-depth gauge is also used when needed.

With the setup process complete, it's time to press on the new bearings.

A special torque wrench is then used to set the pinion's rotating torque. The differential assembly is now complete.

Here's a close-up look at the finished product.

As mentioned earlier, our differential also received one of Zip's heavy-duty covers. This shot of the HD cover shows the welded-in bearing-support blocks at the 3 and 9 o'clock positions.

The blocks preload the carrier-bearing caps, preventing them from flexing or failing under heavy acceleration. The beefier Dana 44 diff used in '85-up manual-trans C4s is equipped with a similar feature from the factory.

This look inside the differential provides a good view of one of the carrier-bearing caps.

Zip builds each of its differentials to precisely match a specific diff cover, thus ensuring just the right amount of bearing preload.

The HD cover is also available as a stand-alone piece, but some machining will be required to match it to your stock diff. Here, a Bridgeport mill is used to achieve precisely 0.003-inch interference between the carrier bearings and the support blocks in the cover.

Our differential came loaded with 3.54 gears in place of the factory-issue 3.07s, a switch that should noticeably improve our '96 coupe's performance at the dragstrip. Check back next month, when we cover the installation process.