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Max
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702 Posts
Discussion Starter #1
Truck is a 2007 1500 classic 4wd ccsb. I had 5:13 gears installed today in rear axel and my shift points were way off in my trans I did not install gear in the front differential because I never use 4wd so I didn't think it would matter. I met up with the guy who does my EFI Live tuning to adjust my gears size and now my truck is still shifting way off. If I lay into it from a dead stop it acts like it wants to shift but it contines to whine and my rpm continues to go up and then will eventually shift. My question is, do I absolutely have to install the 5:13 gears in the front differential to solve the issue? My shifting is way off trough all my gears and my tuner is qualified but even he is stumped. He adjusted my shift points and everything but it's still not shifting correctly. So I'm hoping someone on here can help me figure out what's going on. Once I'm in 4th gear and if I put the peddle to the floor, my rpm continues to climb and won't back down. My speedometer bottoms out at 75 mph and 6000 rpm. I get this horrible vibration which feels like it's coming from the rear driveshaft or the front tires. I did not have this shaking before the regear. Thanks.
 

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The Canadian
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3,241 Posts
Truck is a 2007 1500 classic 4wd ccsb. I had 5:13 gears installed today in rear axel and my shift points were way off in my trans I did not install gear in the front differential because I never use 4wd so I didn't think it would matter. I met up with the guy who does my EFI Live tuning to adjust my gears size and now my truck is still shifting way off. If I lay into it from a dead stop it acts like it wants to shift but it contines to whine and my rpm continues to go up and then will eventually shift. My question is, do I absolutely have to install the 5:13 gears in the front differential to solve the issue? My shifting is way off trough all my gears and my tuner is qualified but even he is stumped. He adjusted my shift points and everything but it's still not shifting correctly. So I'm hoping someone on here can help me figure out what's going on. Once I'm in 4th gear and if I put the peddle to the floor, my rpm continues to climb and won't back down. My speedometer bottoms out at 75 mph and 6000 rpm. I get this horrible vibration which feels like it's coming from the rear driveshaft or the front tires. I did not have this shaking before the regear. Thanks.
You have 4wd, and you installed 5:13 rear gears in the rear axle, and left the front stock??? Please tell me you took out the front driveshaft???
 

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The Canadian
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3,241 Posts
Yeah. Haven't had my front driveshaft in for almost 6 or 7 months.
Ok good haha, otherwise that would be ready to blow front diff, and making everything shift weird, wouldn't be surprised if the vibration would come from that.

Otherwise, I think you need to get a new person to tune your truck, as he should be able to get the shift points correct with all your specs (mods, gears, tires) assuming your tranny is in good working order. And what do you mean your rpms climb if you mat it in OD on the highway, but wont come back down? Will it downshift, then not re-upshift back into OD (4th)? Or it wont downshift atall, just slowly climb rpm/speed? What size tires do you have? Need some info on the truck
 

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Max
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702 Posts
Discussion Starter #5
Ok good haha, otherwise that would be ready to blow front diff, and making everything shift weird, wouldn't be surprised if the vibration would come from that.

Otherwise, I think you need to get a new person to tune your truck, as he should be able to get the shift points correct with all your specs (mods, gears, tires) assuming your tranny is in good working order. And what do you mean your rpms climb if you mat it in OD on the highway, but wont come back down? Will it downshift, then not re-upshift back into OD (4th)? Or it wont downshift atall, just slowly climb rpm/speed? What size tires do you have? Need some info on the truck
I have a 12" lift 37x14r20 tires. Ccsb 2007 silverado classic. Like if in going 50mph and I punch the gas before it would just continue to climb but my rpm woundly ever go that high in 4th. Now when I do it the rpm climb to 6000 and my truck won't go over 75mph but it holds at 6000rpm and just screams like it's hitting the rev limiter or something.
 

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The Canadian
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3,241 Posts
I have a 12" lift 37x14r20 tires. Ccsb 2007 silverado classic. Like if in going 50mph and I punch the gas before it would just continue to climb but my rpm woundly ever go that high in 4th. Now when I do it the rpm climb to 6000 and my truck won't go over 75mph but it holds at 6000rpm and just screams like it's hitting the rev limiter or something.
in 4th (OD) with 37's, on 5.13 gears, @ 75 mph you should be around 25/2600 rpm. Maybe your transmission isn't going into OD, or even 3rd??
In town, does it shift through all gears properly at least?

http://www.angelfire.com/fl/procrastination/rear.html
 

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The Canadian
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3,241 Posts
It town yes. But I do mostly highway... How do I fix it not going into overdrive?
Transmission rebuild haha. Throwing any codes? Could also be a shift solenoid. Try draining the pan fluid, replacing the filter.
 

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Max
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702 Posts
Discussion Starter #9
Transmission rebuild haha. Throwing any codes? Could also be a shift solenoid. Try draining the pan fluid, replacing the filter.
It has no codes. It was shifting come felt normal on my efi live tune until I picked it up yesterday after the new gears got installed
 

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The Canadian
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3,241 Posts
It has no codes. It was shifting come felt normal on my efi live tune until I picked it up yesterday after the new gears got installed
Well the person who tuned the truck after the gears obviously didn't do a job. If it worked fine dropping it off, 5.13's were installed, then re-tuned for, not it drives/shifts improperly. The person tuning the truck is not doing it properly.
 

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Registered
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19 Posts
I have a 2000 Ext. cab GMC Z71 with a 12" lift on 40" tires and have 5.38 gears in the front and back. Not that I see it making a difference with the problem you're experiencing, but I have a Dana 44 3/4 ton straight axle swap on the front and a Dana 60 3/4 ton axle in the back. I'm also running a locker in the rear end.

I have a shift kit and a corvette servo in my trans and a mild tune basically to help out with the lift and tires.

Basically though, my truck shifts a little harder than it would stock but for the most part, the gears and tune make the truck feel as if it's a stock truck (meaning the gearing makes it feel like the truck pulls with the lift and tires as if it's on stock tires with no lift).

If you are sure that the truck is tuned correctly, then I'd take a look at the trans for sure because with that gearing, you shouldn't have any of the problems you're having.
 
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