If anyone needs a free Dana Spicer 70 Repair Manual, here is the link: http://www2.dana.com/pdf/AXSM-0053.pdf I found this while researching changing my front Dana 60 & Rear Spicer 70 ring & pinion gear ratio from 4.10 to 3.54 (or anything close to this). If anyone can give me advice on how to do this (ie: if it can be done, what I need to buy to get this done (special carriers?, best gear sources, special tools, etc.) I would really appreciate it. Thanks for any help.

Get hold of this company and or research the site. They are a very good company to deal with. Both technical and parts wise. http://www.ringpinion.com/

Thanks Wild and Free - looks like a pretty good site with a good selection.

I found a chart that might help anyone else who is thinking about this too:

http://www.motivegear.com/pages/charts/CHART.pdf

--- Update to the previous post...

Here's a gear ratio change speed calculator I found as well:

http://www.csgnetwork.com/rearendgearcalc.html

I guess I might be changing the speedometer gear too.

Another super site and company here also http://quad4x4.com/#Links_To_Our_Other_Web_Pages

If anyone needs a free Dana Spicer 70 Repair Manual, here is the link: http://www2.dana.com/pdf/AXSM-0053.pdf I found this while researching changing my front Dana 60 & Rear Spicer 70 ring & pinion gear ratio from 4.10 to 3.54 (or anything close to this). If anyone can give me advice on how to do this (ie: if it can be done, what I need to buy to get this done (special carriers?, best gear sources, special tools, etc.) I would really appreciate it. Thanks for any help.

Is there something wrong with the gears or just changing them to change them? I'm just wondering cause I wish my truck had 4.10 gears in it and have the 3.54s instead

Is there something wrong with the gears or just changing them to change them? I'm just wondering cause I wish my truck had 4.10 gears in it and have the 3.54s instead

Nothing wrong with them, but with diesel at $4.10 / gallon I can't afford the 4.10 ratio! What a coincidence - 4.10 & 4.10!!! Just filled up the truck yesterday for $92.00 (ouch). If I can give you some advice: don't do it. I'm not sure what you are getting for MPG's but I can bet you are doing better than 12-14 that I am seeing. If you really want to and yours are in good shape you can post your location and I'll let you know if you are within driving distance. Is your truck 4x4?

Nothing wrong with them, but with diesel at $4.10 / gallon I can't afford the 4.10 ratio! What a coincidence - 4.10 & 4.10!!! Just filled up the truck yesterday for $92.00 (ouch). If I can give you some advice: don't do it. I'm not sure what you are getting for MPG's but I can bet you are doing better than 12-14 that I am seeing. If you really want to and yours are in good shape you can post your location and I'll let you know if you are within driving distance. Is your truck 4x4?

I was averaging between 16-17. Yes my truck is a 4x4. My RPMs at 55 MPH stay at 1200. Just seemed low.

I was averaging between 16-17. Yes my truck is a 4x4. My RPMs at 55 MPH stay at 1200. Just seemed low.

That seems really really low. I am doing about 2500 RPM's at 55 or 60. What size tires are you pushing? Did you check the chart at Motive? How does your truck do from a dead stop? I do like the way mine takes off when I want it to. Are you in an automatic or extended cab? 16 or 17 is pretty good either way!

That seems really really low. I am doing about 2500 RPM's at 55 or 60. What size tires are you pushing? Did you check the chart at Motive? How does your truck do from a dead stop? I do like the way mine takes off when I want it to. Are you in an automatic or extended cab? 16 or 17 is pretty good either way!

I have found gear calculator on cargister site and it works quite nice Gear Ratio Calculator

That seems really really low. I am doing about 2500 RPM's at 55 or 60. What size tires are you pushing? Did you check the chart at Motive? How does your truck do from a dead stop? I do like the way mine takes off when I want it to. Are you in an automatic or extended cab? 16 or 17 is pretty good either way!

I've got 35x12.50r20 tires. Didn't check the chart. Accelerates fine from a dead stop. It is actually both an automatic and an extended cab. Sent from my DROID BIONIC using Tapatalk

I too have thought about changing to 4.10 and open diff. I have never pulled the rear cover but it acts like it has a detroit locker. Sometimes after a corner it will kick real hard and loud to one side.

I too have thought about changing to 4.10 and open diff. I have never pulled the rear cover but it acts like it has a detroit locker. Sometimes after a corner it will kick real hard and loud to one side.

Sounds like it could be a factory limited slip setup that didn't have the friction modifier additive put in or has broken down. I drove a 95 CTD yesterday that had a 3.73 ratio. I have to say it felt like an all around good gear. I didn't tow anything with it but it seemed to be the best of both. Had plenty of power but the rpm's don't skyrocket on the highway. Sent from my DROID BIONIC using Tapatalk

It may be just that. I added plenty of that limited slip fluid a few years ago and it did nothing so its definatly wore out if its stock.