Jump to content

Recommended Posts

Posted

18 Sierra sle with 5.3 think it’s 3.08 gears, 6” lift 35x12.5r20. First time buying a Gm truck and I’m starting to regret moving from ford. My 18 f150 with a 5.0 10speed and 35s had no issue towing or driving. This truck has issues doing even 70-75. I just deal with that but towing my canam defender is seriously depressing. Can barely do 65, 66-75 and it’s running 3k rpm and will not upshift what’s so ever, for an around 4500 load with the trailer that’s kind of ridiculous. I would like to be doing 75-80, but usually we run 2 sxs’s per truck which I won’t even attempt right now. I’ve had the truck since November, can’t go smaller on the tires. I actually use the truck off-road going to parks and getting around my buddies property where we keep the bikes. Should I even bother with spending the money on a regear or should I just bite the bullet and buy another truck? Other than the lack of power the truck seems to not mind the load. But I’m not trying to be limited to like 55 mph with two sxs’s on the trailer. Did I buy the wrong truck? Btw trucks in Texas, my local highway is 75 mph. I’ve thought about just buying and old diesel as a tow pig but I have enough stuff to work on, don’t feel like maintaining another vehicle. I would like to keep the truck, it’s nice to have a lighter 1/2 ton in the group. 

F3C05398-4B6E-46E8-8EB3-F7882DC6A188.jpeg

Posted
42 minutes ago, XMR said:

18 Sierra sle with 5.3 think it’s 3.08 gears, 6” lift 35x12.5r20. First time buying a Gm truck and I’m starting to regret moving from ford. My 18 f150 with a 5.0 10speed and 35s had no issue towing or driving. This truck has issues doing even 70-75. I just deal with that but towing my canam defender is seriously depressing. Can barely do 65, 66-75 and it’s running 3k rpm and will not upshift what’s so ever, for an around 4500 load with the trailer that’s kind of ridiculous. I would like to be doing 75-80, but usually we run 2 sxs’s per truck which I won’t even attempt right now. I’ve had the truck since November, can’t go smaller on the tires. I actually use the truck off-road going to parks and getting around my buddies property where we keep the bikes. Should I even bother with spending the money on a regear or should I just bite the bullet and buy another truck? Other than the lack of power the truck seems to not mind the load. But I’m not trying to be limited to like 55 mph with two sxs’s on the trailer. Did I buy the wrong truck? Btw trucks in Texas, my local highway is 75 mph. I’ve thought about just buying and old diesel as a tow pig but I have enough stuff to work on, don’t feel like maintaining another vehicle. I would like to keep the truck, it’s nice to have a lighter 1/2 ton in the group. 

F3C05398-4B6E-46E8-8EB3-F7882DC6A188.jpeg

Scan your QR code in the door jamb on the drivers side , then look for GU4, that is the RPO code for the 3.08 rear end.

 

Posted

Put some 3.73's in it and it will be a world of difference. Trucks with more gears in the transmission need less gear to do the job.

 

Trucks with a 6 speed will still want gearing when it comes to heavy ass rims and tires like you have. Find a 3.73 diff from a junkyard or something and then re-gear the rear end. Will be cheaper this way. Then tune it for the gear change.

  • Like 2
Posted
3 hours ago, XMR said:

18 Sierra sle with 5.3 think it’s 3.08 gears, 6” lift 35x12.5r20. First time buying a Gm truck and I’m starting to regret moving from ford. My 18 f150 with a 5.0 10speed and 35s had no issue towing or driving. This truck has issues doing even 70-75. 

 

The truck you chose was set up for highway cruising, not towing it seems.  Then you made it worse with the lift and 35s.  Regear for 3.73s and have it tuned to match and you won't miss that Ferd.

  • Like 2
Posted

Think 3.73s will be enough? Or should I go up to 4.10s or higher? I don’t mind spending the money on gears and a tune, I just don’t wanna spend the money and it still suck at towing. 

Posted

With less than 20ft lbs of tq difference and about 40 Hp. The difference should be negligible. The ford probably had deeper gears. Where it makes its peak plays a role too. Gearing is the problem. That’s not the trucks fault. Another misconception is you need lift and big tires to go off road. I worked off road on pipelines most of my life with only bfgs. Sure some people like the look. The old saying goes you have to pay to play. The cost is 411s or 456 and gas mileage, front end parts etc etc.

  • Like 1
Posted

You bought the wrong truck to tow with then made it worse with the mods. Gear choice 373 will better and more suited for highway speeds, 411 will raise rpms and may keep it in a better power range. 456 I wouldn't do.

The only way to know is try it. 

 

Posted

I guess I’ll start pricing out gears, I’m not planning on pulling more than like 6500 with two bikes, gear, spare parts, and tools. I wouldn’t think that would be to much for a half ton, we don’t even have hills around here. Anyone on 35s with 3.73s or 4.11s have any issue towing this weight? I also don’t really care about gas mileage, I daily a service truck. 

  • Like 1
Posted
10 hours ago, XMR said:

Think 3.73s will be enough? Or should I go up to 4.10s or higher? I don’t mind spending the money on gears and a tune, I just don’t wanna spend the money and it still suck at towing. 

 

This is my daughter's NHT Sierra with 3.73s and the 6.2 motor.  It's been running the lift and tires for ten years now without issue and can pull a house down still.  She hauls hay with it sometimes and it effortlessly pulls trucks out of the mud when they're out playing in the woods or on the beach.  The taller tires (35s) have reduced the axle ratio to being akin to 3.42s.

 

Someday we'll regear it to 4.10s so the gearing will be more or less back to stock 3.73s with the 35s.  We talk about going to 4.56s which would be akin to 4.10s but if she goes to 33 inch tires or removes the lift than that would be an additional expense.

IMG_7578001.jpg

  • Like 1
Posted (edited)

As others have stated those 3.08 gears are for highway driving then you really killed it by adding the 6" lift creating alot of wind drag at highway speeds then you added the way heavier tires, regear to a 3.73 or a 4.10 in both front and rear and you will be good. With 3.08 gears and 35" tires your truck is really running about a 2.83 gear that's why it's a dog. It's not the trucks fault.

Edited by Silverado4x4
  • Like 1
Posted

Speed engineering have a twin turbo kit for fairing cheap for what it comes with… should add another 150-200hp without issue. It’ll love those 3.08. 😈😈😈 

Posted

I would definitely say get 3.73's or if you can get them for the front and rear go with 3.90's

 

 

 

 

 

 

 

 

 

  • Like 1
Posted
6 hours ago, Homewrecker007 said:

I would definitely say get 3.73's or if you can get them for the front and rear go with 3.90's

 

 

 

 

 

 

 

 

 

Shouldn't 4WD have same gears on front and rear?

  • Like 1
Posted
5 hours ago, mikeyk101 said:

Shouldn't 4WD have same gears on front and rear?

Yes, I said that because I'm unsure if there is ring and pinion for the front in 3.90 ratio 

Posted (edited)
3 hours ago, Homewrecker007 said:

Yes, I said that because I'm unsure if there is ring and pinion for the front in 3.90 ratio 

Haven't seen those in years. 

Edited by swathdiver

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Latest Articles

  • Posts

    • Have considered installing a DC to DC charger in your camper to replace your isolator?  
    • Common failure.  You need to replace the fuel door housing.   The painted cover transfers over to the new housing.  To remove the old one there is 4 spots where you poke the plastic to release it.  
    • No such thing as regenerative braking on a pure ICE vehicle.     Regenerative braking is the re-capture of energy from electric motors and stores it in the battery pack.  So hybrids, PHEV and EVs have regenerative braking.     What you are seeing is the charging system changing modes is all.  Its likely entering charge mode for some sort of reason is all.  All of the charging modes will be listed below.   As for L10 vs D.  L10 turns off automatic grade braking.  L10 puts you in control of grade downshifts where in D it will automatically do it based on brake pedal position and other factors.  Otherwise L10 and D drive exactly the same aside from that one aspect.    Battery Sulfation Mode The BCM will enter this mode when the interpreted Generator output voltage is less than 13.2 V for 45 minutes. When this condition exists the BCM will enter Charge Mode for 2–3 minutes. The BCM will then determine which mode to enter depending on voltage requirements.   Charge Mode The BCM will enter Charge Mode when ever one of the following conditions are met:   Windshield wipers are ON for more than 3 s. Climate Control Voltage Boost Mode Request is true, as sensed by the HVAC control module via serial data. High speed cooling fan, rear defogger, and HVAC high speed blower operation can cause the BCM to enter the Charge Mode. The estimated battery temperature is less than 0°C (32°F). Battery State of Charge is less than 80%. Vehicle speed is greater than 145 km/h (90 mph) A current sensor malfunction exists. System voltage is determined to be below 12.56 V When any one of these conditions is met, the system will set targeted generator output voltage to a charging voltage between 13.9–15.5 V, depending on the battery state of charge and estimated battery temperature.   Fuel Economy Mode The BCM will enter Fuel Economy Mode when the estimated battery temperature is at least 0°C (32°F) but less than or equal to 80°C (176°F), the calculated battery current is less than 15 A and greater than −8 A, and the battery state-of-charge is greater than or equal to 80%. Its targeted generator output voltage is the open circuit voltage of the battery and can be between 12.5–13.1 V. When fuel economy mode is active, the generator is not charging, only maintaining open circuit battery voltage. The BCM will exit this mode and enter Charge Mode when any of the conditions described above are present.   Headlamp Mode The BCM will enter Headlamp Mode when ever the head lamps are ON (high or low beams). Voltage will be regulated between 13.9–14.5 V.   Start Up Mode When the engine is started the BCM sets a targeted generator output voltage of 14.5 V for 30 s.   Tow/Haul Mode (if applicable) Pressing the Tow/Haul Mode button located on the center stack, the vehicle system voltage is raised and the remote (non-vehicle) battery will be charged. Having the headlamps on will raise the system voltage and if the Tow/Haul button is applied it will not serve any purpose. The voltage is regulated between 13.9-14.5 V.      
    • Hello from Australia Just sharing that there is now a way to delete the active shutters entirely with just a plug in module. Opens up tons of room to light bars etc.
    • I have an observation and a question... 1) I watch the voltage closely because I have had to dial in the cut-in/cut-out voltages of the battery separator to my camper.  The "smart" charging drives me nuts.  Anyway, I noticed that when coasting for a while, and especially if lightly using the brakes (though not necessary), the voltage goes up from mid/high-13 volts to mid/high-14 volts.  Then it drops back down after stopping or going again.  Consistently!   The only explanation I can come up with is REGENERATIVE BRAKING!  Well, maybe that's a little bit of an exaggeration, but it's certainly free extra battery charging.   2) Driving on mountain roads I will use L and vary the max gear.  Things straighten out and I end up in L10.  Sometimes I leave it there for a while.  Is there any difference between L10 and D?   
  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...