Jump to content

Gear Change 9.5" 12 bolt

CAtaylor

By CAtaylor
in Engines & Drivetrain

Recommended Posts

rgiles675 Enthusiast

rgiles675

Posted
Posted

Check out eastcoastgears.com out of North Carolina. They have the parts to setup the rear end on the 2014's and claim to have done a handful in house. I just ordered the parts the other day and my truck is at the local shop now. They claim a new posi duratrack by Yukon, a 9.5" 14 bolt gear set, a yoke adapter kit, a diff cover spacer and their master install kit will get it done. The front end of our 4x4's are the same 8.25" reverse IFS gear set as previous years. Give them a call and hit option # 2. They know their stuff. Hopefully my shop here in Ohio will have everything together by this evening and I will let you know how the truck is. I went with the 410's to replace my 3.42's. 35" tires and a 6" lift is what I have too

 

Greatly Appreciated!

  • Replies 131
  • Created
  • Last Reply
badchevy Enthusiast

badchevy

Posted
Posted

 

Greatly Appreciated!

No problem. Keep in mind that I have heard the early round of '14 trucks had the '13 trucks 8.5" rear end. The later '14's have a 9.5" rear end. I found out the hard way and first ordered 8.5" gears before I talked to Eastcoast. The best way to find out is to count the bolts on your rear differential. The 8.5" set on the older style has 10 bolts and the newer style on most '14's 9.5" has 12 bolts hold on the diff cover. Someone else can chime in if I am wrong, but I believe this is correct.

CAtaylor Enthusiast

CAtaylor

Posted
  • Author
Posted

Check out eastcoastgears.com out of North Carolina. They have the parts to setup the rear end on the 2014's and claim to have done a handful in house. I just ordered the parts the other day and my truck is at the local shop now. They claim a new posi duratrack by Yukon, a 9.5" 14 bolt gear set, a yoke adapter kit, a diff cover spacer and their master install kit will get it done. The front end of our 4x4's are the same 8.25" reverse IFS gear set as previous years. Give them a call and hit option # 2. They know their stuff. Hopefully my shop here in Ohio will have everything together by this evening and I will let you know how the truck is. I went with the 410's to replace my 3.42's. 35" tires and a 6" lift is what I have too

You got it man, hope the install goes good for you. I would have replied sooner but have been in England the past 6 days, their phone data service sucks over there if you have a US phone.

  • 1 month later...
DCOX Enthusiast

DCOX

Posted
Posted

Check out eastcoastgears.com out of North Carolina. They have the parts to setup the rear end on the 2014's and claim to have done a handful in house. I just ordered the parts the other day and my truck is at the local shop now. They claim a new posi duratrack by Yukon, a 9.5" 14 bolt gear set, a yoke adapter kit, a diff cover spacer and their master install kit will get it done. The front end of our 4x4's are the same 8.25" reverse IFS gear set as previous years. Give them a call and hit option # 2. They know their stuff. Hopefully my shop here in Ohio will have everything together by this evening and I will let you know how the truck is. I went with the 410's to replace my 3.42's. 35" tires and a 6" lift is what I have too

How'd the install go? Everything turn out ok? How do u like the 410?

badchevy Enthusiast

badchevy

Posted
Posted

How'd the install go? Everything turn out ok? How do u like the 410?

I'm not quite happy with the front install, but that could be the shop who did the work. They are trying to tell me the front end is slightly different even though it still takes the 8.25" gear as the previous years. The crush sleeve didn't work with the install kit, so they used a solid spacer that was machined. No big deal as a lot of folks setup their pinion with a hard spacer and not the crush sleeve. I had the shop setup a new pattern after I drove the truck 500 miles with the first install. I am still hearing a faint whining noise and occasional rattle under acceleration from the front. It could be the gears, but I have a feeling it is the setup. It gets louder with 4 wheel drive engaged. I really like the feel of the rear end with the duratrack carrier and the adapter kit works really well.

 

Overall the 4.10 seems the way to go though. I kicked around the 4.56, but I didn't want to lose too much mpg on the highway. Right now when running 65-70 I am at 1900 rpms. I would rather be around 1700, but in town the mpg has seemed to improve. If I could have the best of both, 3.73 would be perfect for highway and something like a 4.56 would be good for in town. I guess the 4.10 is about the right median for mix driving.

DCOX Enthusiast

DCOX

Posted
Posted

I'm not quite happy with the front install, but that could be the shop who did the work. They are trying to tell me the front end is slightly different even though it still takes the 8.25" gear as the previous years. The crush sleeve didn't work with the install kit, so they used a solid spacer that was machined. No big deal as a lot of folks setup their pinion with a hard spacer and not the crush sleeve. I had the shop setup a new pattern after I drove the truck 500 miles with the first install. I am still hearing a faint whining noise and occasional rattle under acceleration from the front. It could be the gears, but I have a feeling it is the setup. It gets louder with 4 wheel drive engaged. I really like the feel of the rear end with the duratrack carrier and the adapter kit works really well.

 

Overall the 4.10 seems the way to go though. I kicked around the 4.56, but I didn't want to lose too much mpg on the highway. Right now when running 65-70 I am at 1900 rpms. I would rather be around 1700, but in town the mpg has seemed to improve. If I could have the best of both, 3.73 would be perfect for highway and something like a 4.56 would be good for in town. I guess the 4.10 is about the right median for mix driving.

Thanks for the info. It is pretty hard to get any regear info on these newer trucks. I plan to do my 4.10s around Christmas. Thanks again

Mike1220 Senior Enthusiast

Mike1220

Posted
Posted

I'm not quite happy with the front install, but that could be the shop who did the work. They are trying to tell me the front end is slightly different even though it still takes the 8.25" gear as the previous years. The crush sleeve didn't work with the install kit, so they used a solid spacer that was machined. No big deal as a lot of folks setup their pinion with a hard spacer and not the crush sleeve. I had the shop setup a new pattern after I drove the truck 500 miles with the first install. I am still hearing a faint whining noise and occasional rattle under acceleration from the front. It could be the gears, but I have a feeling it is the setup. It gets louder with 4 wheel drive engaged. I really like the feel of the rear end with the duratrack carrier and the adapter kit works really well.

 

Overall the 4.10 seems the way to go though. I kicked around the 4.56, but I didn't want to lose too much mpg on the highway. Right now when running 65-70 I am at 1900 rpms. I would rather be around 1700, but in town the mpg has seemed to improve. If I could have the best of both, 3.73 would be perfect for highway and something like a 4.56 would be good for in town. I guess the 4.10 is about the right median for mix driving.

So for someone who does mostly highway driving you would recommend 3.73 gears? I'm not worried about in town mileage. How much 'get up and go' do you think would be lost by going to a 3.73 instead of a 4.10? Just curious. I plan to do this not long after (or at least as soon as I can) I put on bigger tires. Looking to put on some 34s and then 35.5s after those wear out.

badchevy Enthusiast

badchevy

Posted
Posted

Well GM puts a bigger rear end with a 3.73 in some of the newer half tons when they do a high country with 6" pro comp lift and 33"-35" tires. If you are going from a 3.08 to 3.73 you will see a nice difference. 3.42 to 3.73 may yield minimal difference but still be a nice gain. I went from 3.42 to 4.10 to make sure I had enough. On the highway 3.73 would run the rpm a little lower than 4.10. Only a couple hundred but enough to make a difference. I can still get 16-17mpg avg on hwy with my 410s, 6"lift and 35 tires

 

 

Sent from my iPhone using Tapatalk

Mike1220 Senior Enthusiast

Mike1220

Posted
Posted

any idea

 

Well GM puts a bigger rear end with a 3.73 in some of the newer half tons when they do a high country with 6" pro comp lift and 33"-35" tires. If you are going from a 3.08 to 3.73 you will see a nice difference. 3.42 to 3.73 may yield minimal difference but still be a nice gain. I went from 3.42 to 4.10 to make sure I had enough. On the highway 3.73 would run the rpm a little lower than 4.10. Only a couple hundred but enough to make a difference. I can still get 16-17mpg avg on hwy with my 410s, 6"lift and 35 tires


Sent from my iPhone using Tapatalk

 

any idea on how much higher that would be if you did the 3.73 instead? Also would I need to change to the larger rear end or just use the conversion kit? I currently have 3.42s and want to keep my highway mileage as high as I can. I am getting a Diablo tuner soon to help with that a little bit

badchevy Enthusiast

badchevy

Posted
Posted

You can use the same conversion kit I used and run the 3.73. Swapping the whole rear end would be expensive as the one I mentioned on some of the high country's is a different axle with a different size differential. With the kit you can choose ratio size that is a 9.5" gear

 

 

Sent from my iPhone using Tapatalk

badchevy Enthusiast

badchevy

Posted
Posted

Thanks for the info. It is pretty hard to get any regear info on these newer trucks. I plan to do my 4.10s around Christmas. Thanks again

I know what you mean! I am learning a ton about these gears. I wish I had the tools to have done the setup and install myself instead of a shop.

 

 

Sent from my iPhone using Tapatalk

Mike1220 Senior Enthusiast

Mike1220

Posted
Posted

You can use the same conversion kit I used and run the 3.73. Swapping the whole rear end would be expensive as the one I mentioned on some of the high country's is a different axle with a different size differential. With the kit you can choose ratio size gear that is a 9.5" gear

 

 

Sent from my iPhone using Tapatalk

 

 

That's what I thought and wanted to make sure. Do you know how much better the mileage would be? Also would the 4.10s be better in the long run incase if I ever take this truck off roading / mudding. I don't plan to go do anything hardcore so I would think the 3.73s would be good.

You can use the same conversion kit I used and run the 3.73. Swapping the whole rear end would be expensive as the one I mentioned on some of the high country's is a different axle with a different size differential. With the kit you can choose ratio size gear that is a 9.5" gear

 

 

Sent from my iPhone using Tapatalk

 

 

That's what I thought and wanted to make sure. Do you know how much better the mileage would be? Also would the 4.10s be better in the long run incase if I ever take this truck off roading / mudding. I don't plan to go do anything hardcore so I would think the 3.73s would be good.

badchevy Enthusiast

badchevy

Posted
Posted

Also, when I had the stock 3.42s and my current setup I was running around 1300 rpms at 70mph. I tuned to match tire size with a Diablo Intuner. Since I am now at 1900 and the tuner adjusted for 4.10, I'd imagine 3.73 would be around 1500 or 1600 rpms which is close to stock with 3.42s running at 70

 

 

Sent from my iPhone using Tapatalk

badchevy Enthusiast

badchevy

Posted
Posted

 

 

That's what I thought and wanted to make sure. Do you know how much better the mileage would be? Also would the 4.10s be better in the long run incase if I ever take this truck off roading / mudding. I don't plan to go do anything hardcore so I would think the 3.73s would be good.

 

 

 

That's what I thought and wanted to make sure. Do you know how much better the mileage would be? Also would the 4.10s be better in the long run incase if I ever take this truck off roading / mudding. I don't plan to go do anything hardcore so I would think the 3.73s would be good.

I would imagine mpg could be 1-2 difference. 4.10 would definitely be better down low for off road. Shorter gears have a better crawl speed. The taller the gear the easier it is on the highway. I haven't driven a truck with 3.73s. If you are considering that ratio, I would check online for a dealer that has one of the lifted high country models with 3.73. Test drive to get a feel. Wish I had done that before my install

 

 

Sent from my iPhone using Tapatalk

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.4k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,866
    Total Members
    8,960
    Most Online
    Greg3160
    Newest Member
    Greg3160
    Joined

  • Who's Online   3 Members, 0 Anonymous, 424 Guests (See full list)

  • Latest Articles

  • Posts

    • MANGOAL
      Mangoal or FitcamX OEM Dashcam?

      By MANGOAL · Posted

      Late reply, but yes—it works on the SLT trim. Compatibility comes down to the plastic shroud shape behind your mirror, not the trim badge itself. On the SLT with auto-dimming, it uses a plug-and-play Y-harness off the mirror/rain sensor power, so no need to run wires down to the OBD port. If anyone's ever unsure about fitment, just drop a photo of your mirror housing and we can double-check it.   Appreciate the detailed feedback on the install! On the windshield glare—we actually took feedback like yours and developed a dedicated CPL (polarizer) filter to cut down dash reflections on sunny days. If you're still running the cam, shoot me a DM. I'd be happy to send a CPL filter over for you to test out—no charge. 
    • davester
      2002 GMC Yukon

      By davester · Posted

      There are no stickers in your glovebox?
    • davester
      Weight limit in bed

      By davester · Posted

      Look at the numbers on the stickers in the door jam...
    • EJS2015
      Actual Full Screen CarPlay on Refreshed Silverado/Sierras.

      By EJS2015 · Posted

      Yes, every time the developer updates his code, you must recompile. I will private message you with the latest because it changes pretty much with every version.
    • Grumpy Bear
      Transmission Temperature Hitting 220s

      By Grumpy Bear · Posted

      After I wrote that reply I went for a ride. 85 F out. So trans started at 85 F and it shifted the same as it did an hour latter at 168 F. I've never actually recorded the to cold to shift point but it is under 32 F before they start hanging on to a lower gear or leaving the converter unlocked. Both intended to heat fluid.    Yes, brake or bake. Absolutely.      Your welcome. True research ended decades ago. Field trials are still in play.    There is a thing called oxidation onset temperature. This is the heat related oxidation not the O2 exposure kind. For mineral oil that starts at 140 F. So what happens after 140 F? Each 20 F cuts fluid life in half! Does using a Full Synthetic improve that? Yes! By how much? Depends on the base oil type and a few other factors. But enough to notice. Some esters are even higher. There are even synergies between types the will raise it higher than any one component is alone.    Then there is "Hindered" oils. Antioxidant additives. Hindered Polyol Esters can sit at 500 F for years in a turbine.   When a blender brags his oil will 'take 500 F" in service he doesn't specify for how long. Water will dance on a 500 F hot plate for several seconds. @newdude put up a chart showing the relationship between fluid temperature and it's life in an automatic transmission. Here's a version of that chart for Group III based oils. These temperatures are those in the pan as observed as 'normal'. that is you drive as you do for as long as you do under what load you ask of it and whatever that temperature is this graph applies to. Flash temperatures of a few minutes isn't what his means.    Note that fluids held at a constant 240 F have a service life of only 20K miles. 220 F explains the factory exchange limit, eh? My equipment I keep under 180 F and I'm good if the cooler will hold it as low as 140 F. But that's me.   

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...