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

    342,759
    Total Members
    8,960
    Most Online
    DM22
    Newest Member
    DM22
    Joined

  • Who's Online   2 Members, 0 Anonymous, 2,507 Guests (See full list)

  • Latest Articles

  • Posts

    • B14Sierra
      Cam chain tensioner question

      By B14Sierra · Posted

      So I'm in the middle of a DOD AFM delete on my 6.2 L86 Sierra. I had a pick holding the tensioner but after I got the Cam phaser gear off I was cleaning off all the rtv and apparently I didn't have the pick seated far enough in. I bumped it and the tensioner sprang forward.  I think everything is good but I want a second opinion. The top of the tensioner is just a looped piece of plastic that rides in that channel right? There is no spring or anything is there? I got the gear and chain back on and it seems tight and everything looks right. I'm hoping nothing fell out.
    • dna9656
      No low range 4 x 4

      By dna9656 · Posted

      My 2015 1500 LTZ Silverado suddenly won't go into 4 x 4 low. It will go into 4 x 4 high.
    • asilverblazer
      Transmission Woes :-(

      By asilverblazer · Posted

      Yep, just a quick reference point.    My main point being I’d do a thousand other things before I’d pay 10k for a transmission.    Speaking in ignorance cause I don’t look at these trucks, what is it worth? 20k?
    • asilverblazer
      Intermittent no-code issues on 2022.5+ V8 trucks — what did the shop fail to capture?

      By asilverblazer · Posted

      I think users are going to want to pick their monitored parameters, which parameters they want to see first.    It should probably start with baseline at a minimum and adjust to learned, but be able to overlay baseline for comparison.   A simple severity level would be able to determine what type of alerting is appropriate or user selectable.    Why not use the OBD port though?   I think a phone connection would be a good idea, push notifications type deal.   Number 1 issue is having data is useless if you don’t know what the data should be under normal conditions. 
    • Chuck FB
      summer road trips in the 2026 2500HD

      By Chuck FB · Posted

      I thought I would use your thread and add to it as I just did my first longer drive with my truck in the last couple of days. I drove from the Grande Prairie area of Alberta down to Edmonton and most of where I drove in the city was the ring road so fairly free flowing but a bit of stop and go as well in the city. Stayed the night and returned home and not too many stops along the way each way but every restart and certainly every cold start sets it back for fuel mileage. Why I say that is I see some people will cherry pick a fuel mileage leg after the vehicle had been warmed up driveline wise before hand and its a forgiving ( easy rolling drive leg for example ) and call that their fuel mileage which can give a false perception of reality. I was not heavily loaded at all but never the less the flip bak cover, rubber bed mat, various tools etc and extra jerry cans of fuel all way up to a few hundred pounds of dead weight so its not an empty truck. The cold inflation tire pressures are set more near the freezing point so once they are warmed up driving I was showing 45 front and over 40 rear and realize high inflation pressures would help a little in fuel mileage but certainly not the ride on our crap sections of highway. The weather was good so was not raining as that can really drag mileage down, in fact I had a bit of a tail wind on average driving home. Most people on here would never have driven on that freeway to visualize it but its got a fair bit of rolling type of landscape with numerous river valleys. For the most part I had it on cruise set to 62 although kicking it off if I caught it in time before it started down shifting and self braking going down the grades. Most of the more substantial grades its shifting into 7th I believe as 8th just doesn't have it. Total distance round trip was 643 miles and my overall average and I did refuel three times in all, figured out to 17.65 miles per US gallon. My best fuel mileage section refuel within all of this figured out to 18.46 and these are all hand calculated figures. I find if anything that the trucks computer can be over optimistic, sometimes its pretty close but other times its stretching it. On paper persay in theory the truck would have just about made it on fumes for that whole drive without refueling once.    Which made me think of the topic thread of the wonder if these trucks could do 20 mpg and that is a good question, certainly would have to be on an easy going flat highway, no head wind, the right temperature, not packing around a bunch of dead weight and puttering along even slower than I was I would suspect and going steady and not stopping to smell the flowers or take a piss !. It probably is possible but not without effort to attain that with the wind resistance and weight of these trucks. Of course on my drive most people are passing me if they have the power as per loaded highway tractors, never mind a lot of speedy vehicles but the speed limit is 68 and most are at or well over that. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...