Lowering differential gear ratio. Dana 44

[TRybas]

Looking for some guidance/ confirmation from anyone that has changed out the ring and pinion to get a little more high end out of the old girl. I’ve read through what I could find here and have talked to Jake about his setup. Not trying to get in a debate here about them being old work horses not meant for speed yada yada yada. Please keep it to the mechanics.

Seems doable than I got to reading somewhere about different thickness gears so I called spicer tech support to confirm. The gentlemen from spicer seemed knowledgeable and said to go lower than 3.92 (current setup) I would have to change out the carrier as well which they do not offer.

My goal is to be able to cruise around 60-65mph. My current set up is 1960 V6 305A 4-wheel-drive with an SM420. Dana 44 front and back at 3.92.

I was looking at the 3.54 part# 22856-5x or the 3.31 part# 706017-2x. Obviously my truck is 4x4 so I’d have to do both front and rear. Could get pricey and I don’t want to start pulling things apart to find I didn’t order the right stuff. If someone could confirm they have done so and specific parts it would be greatly appreciated.

I’ve also considered putting a gear vendor overdrive so I gave them a call. Their bolt on over drive is 14” long (and back ordered for several months). Taking 14” out of the drive shaft would put it at a pretty sharp angle. Not sure I am comfortable doing that. (See pics) Thoughts?

Regards, T.J.

[Ed Snyder]

Originally Posted by TRybas

Looking for some guidance/ confirmation from anyone that has changed out the ring and pinion to get a little more high end out of the old girl.

Seems doable than I got to reading somewhere about different thickness gears so I called spicer tech support to confirm. The gentlemen from spicer seemed knowledgeable and said to go lower than 3.92 (current setup) I would have to change out the carrier as well which they do not offer.

My goal is to be able to cruise around 60-65mph. My current set up is 1960 V6 305A 4-wheel-drive with an SM420. Dana 44 front and back at 3.92.

I was looking at the 3.54 part# 22856-5x or the 3.31 part# 706017-2x. Obviously my truck is 4x4 so I’d have to do both front and rear. Thoughts?

Regards, T.J.

My '62 Suburban came from the factory with 3.92 gears. Prior to my purchase 25 years ago, someone had changed the rear gears to 3.54, but neglected to do anything with the front end. I found that out after driving it 1300 miles from Phoenix, AZ, and attempting to drive up my steep gravel driveway. After I locked in the hubs and put the T-case in 4 high, the truck refused to move forward more than a few inches. That's when I realized the mis-match in gears. I had a local 4x4 shop change the front to 3.54 to match the rear. With 32" tall tires I have no problem with freeway cruising. It turns 2600 RPM at 70 MPH.

[duallyjams]

A lot of good info here http://www.billavista.com/index.html

To my knowledge the same carrier works with 4:10 and down, so if your going from 3:92 to 3:54 you should be able to use the same carrier.