Regearing the Volvo 240 Rear End

The joys of doing custom work. I'm changing out the gear ratio in my 24v wagon from 3.73 to 3.08. With all the power it now has, first gear was useless and I wanted to drop the the highway speed RPM's.

The rear end is a Dana 30 from a Volvo.

Dana 30 parts are pretty common and I ordered a gear set and bearing kit. The kit said "Fits Volvo."

Well the O.D. on the inner pinion bearing was too small so I ordered it's Volvo replacement. Now the I.D. of the new bearing was too big and it was loose on the new pinion shaft.

After a bit of searching on the Timken site, I came up with one that had the right dimensions and was listed as a pinion bearing.

The new bearing and race arrived and the I.D and O.D. are fine. But a new issue popped up... The pinion depth is set by adding or subtracting shims from behind the race which means the race must be removed several times as the shims are replaced. I had made a "set up" race that can be easily removed by grinding down the O.D. of the original race. The new bearing has a different taper so it won't sit fully in the set up race. That means I need to make a new set up race and order its replacement.

All the research I did on this said the new ratio I am using required a different carrier. Well, that might be true for a Jeep Dana 30 but not with the Volvo Dana 30! While the carriers may be the same, the Volvo housing is different. I roughly set the pinion depth and put the 'new' carrier in and the fit wasn't even close. Swapped the ring gear to the 'old' carrier and that worked. So I now have a starting point for setting the pinion depth, preload, and backlash. One good note, the 'old' carrier is a limited slip!

4/2 Update

Volvo used two different housings for their Dana 30 differential 1030 and the more robust 1031. I have the 1031. It appears the gear set I ordered was meant for the 1030 which explains the different pinion bearings, the carrier difference and the difficulty I am having setting the pinion depth.

Even after machining 0.070 off the passenger side carrier boss to move it closer to the pinion and get the correct backlash, the gear pattern was still at the top of the teeth. The pinion could not be moved any closer to the center line as it would hit the LSD carrier. Shim stock is being delivered today and I will try spacing the the ring gear out which will give more flexibility with the pinion depth and backlash adjustment.

4/5 Update

Shimming the ring gear 0.037" improved the gear pattern but it was still not down far enough to show full contact. I put the original 3.73 gears in to check its gear pattern and it was perfect.

Despite their listing that it fits the 1990 Volvo 240, the USA Gear 3.08 ring and pinion set does not fit the 1031 housing.

The search goes on for a Volvo 240 rear end with 3.31 gearing...