1957 Corvette RestoMod Story – Page 14

C4 Dana 36 Bearings & Seals

The 1995 C4 Corvette rear-end I bought came from an automatic car.  Only the Dana 36 was used in the C4 automatics.  The Dana 44 axle was used in manual transmission C4’s, and it’s beefier.

My plan is to replace the stock 3.07:1 ring & pinion ratio with the lower 3.54 ratio.  In gear-speak, the higher the ratio the lower the gearing.  With my Keisler (now Silver Sport ) T56 six-speed manual transmission, the 3.07 ratio would have my rpm’s near idle at highway speeds – not good.

And since this axle has been sitting for a while, I decided to replace all bearings and seals while it’s disassembled.  Read along as we enter the scary world of “pumpkins”!

1957 Corvette RestoMod Chassis Build Instructions
Click HERE to be directed to the Bookstore

Corvette Dana 36 off the car and open

A quick way to check if you have a Dana 36 or 44 is the top center bolt.  The Dana 36 has one, the 44 does not.  Pictured left is the “batwing” carrier cover removed.  It’s nicknamed the batwing because the cover has integrated support arms.

Also notice the stub axles and yokes that stick out each side of the carrier.  The yokes mate up with the axle shaft yokes using universal joints.

The center of the carrier holds the differential (called the “case”).  Many people confuse the carrier with the case – but think of it like this: the carrier holds the gearing, while the case transfers power to the axles.

Without the right tool, the hardest job is removing the stub axle snap rings (right).  They “snap” around the ends of the stub axles to retain the axles in the case.  Even experienced mechanics have a problem with these.

I tried for hours, and used three different styles of snap ring pliers, to remove these but wasn’t successful until I bought the right tool from HandsOn Tools  for $30.  The prongs of these pliers are large enough to hold the snap rings and spread them wide enough to remove easily – about 30 seconds!

Dana 36 snap rings in the differential

Once the snap rings are out, removal of the stub axles is a snap (sorry, I couldn’t resist).

Dana 36 Stub Axle removal

The ends of each stub axle have splines.  The shaft of the stub axle goes through the carrier in to the center of the case where it mates up with the case’s side gears and clutch plates.

Dana 36 Stub Axle spline end

Dana 36 Differential Removal

The differential (the ‘case’) is held in place by bearing caps – and as the name suggests, bearings allow the case to spin in the carrier.  Once the bearing caps are removed, the case can be pried from the carrier (left).

It may be difficult to pry the case out, so I clamped the pinion yoke in my bench vise.  When the case is out, the fun begins!

Chapter 9 of my book covers the complete rebuild in unbelievable detail and photos.

At some point after the case is removed, you’ll need to clean the carrier.  I used brake cleaner for the inside – what a greasy mess.  At right, a Roloc disk and die-grinder quickly remove the old gasket material from the carrier cover flange.

WARNING: Be careful with this tool!  The carrier is cast aluminum and you can easily grind away the needed ridges on the flange.  The ridges provide better adhesion for the new gasket material.  Better to use a chemical way to remove the old gasket.

Dana 36 Carrier Flange Cleaning

Dana 36 Axle Seals Removal

The axle seals need to be removed to get at the axle bearings, seen above.  This one was stubborn and a screwdriver and hammer were needed – BUT, I slightly damaged the inner wall of the seal bore!  Dang-it.

No problem though, with a little light sanding, the mar came out and the new seal fits snugly.

Needless to say, if you use a blade screwdriver, be careful around the edges of the aluminum carrier.

Harbor Freight 12-ton Shop Press

All the bearing replacement steps in Chapter 9 use a 12-ton press I got from Harbor Freight – not expensive.  It might have been the best tool purchase of the entire project.  Get one or life will be miserable.

Many jobs other than the carrier rebuild also used my handy little shop press.

Dana 36 Axle Bearings

Stub axle bearings are pressed into the carrier walls (above).  These are roller-pin types and allow the stub axles to rotate.

I also replaced the pinion and differential bearings and all bearing cups.

The Dana carriers have unique bearing lips everywhere, and it’s important to know how the bearings are removed and installed without damaging the carrier lips – crucial!

I used replacement bearings by Timken, and I only found them at Autozone  .

There are other bearing makers besides Timken, but I found their fitment to be troubling.  Timken bearing are original bearings for the Dana 36 and their fitment was perfect.

Also, when you buy full kits to rebuild the Dana 36, be careful of what you get.  The Dana 36 is such a rare piece that sometimes the replacement parts are not correct.  But, the Dana 44 was used in many other cars besides Corvette, so replacement parts for it are more plentiful.

Chapters 9 and 10 of my RestoMod book have complete instructions on how to rebuild the Dana 36 Carrier and Differential.

Back to Page 13                                                                   On to Page 15