Forum Discussion

Gruu's avatar
Gruu
Explorer
Sep 21, 2016

TV rating and changing gears.

Posted this on the wrong forum, sorry. I tow my Jayco hybrid trailer, weight 4300 lbs. with a Chevy Silverado 4.8l with 3.23 gears. Owners manual says max trailer weight should be 4700 lbs. I know that is pretty close. The owners manual also says the same truck with 3.73 gears has max trailer weight of 6700 lbs. If I change the gears I would pick up at least 2000 lbs. extra capacity. How much would that gear change effect my RPMs? I run about 2000 RPMs at 60 MPH now. The truck tows the trailer fine but I would like a little extra leeway. Who can help?
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  • ScottG's avatar
    ScottG
    Nomad
    Sep 22, 2016
    Some ECM's will only have a list of stock ratio's to choose from. The RAm is that way although there is a back door way to change it through the antilock brake module with the right tuner.
  • Calicajun's avatar
    Calicajun
    Explorer
    Sep 21, 2016
    Well for me it worked out better in the long run anyway. Our Ram 2500 diesel pulls like a dream for us.

    As for the shop that did the work, they are nationally known for that type of work. So I have not real idea as to way it wouldn't work, and no I don't completely trust anything GM has to say.

    My point to my original post was for the OP to just be careful and check out everything before starting the work.
  • time2roll's avatar
    time2roll
    Nomad
    Sep 21, 2016
    Some may need the computer updated to show the correct speed but any whine is the gears not set up right.
  • Campfire_Time's avatar
    Campfire_Time
    Explorer
    Sep 21, 2016
    2wd or 4wd? 2wd is relatively cheap and easy to do. 4wd is expensive and complicated to change gears.

    Is your trailer 4300# dry weight or GVWR? If that's the GVWR you might need to take mountains a little slow but you still have plenty of capacity. If it's 4300# dry, well you'll never tow it that light. You're already over capacity.
  • mkirsch's avatar
    mkirsch
    Nomad II
    Sep 21, 2016
    Yes, a whine from the differential is due to improper gear setup. Has nothing to do with the computer. All the computer will do is count the miles wrong and show you a skewed reading on the speedometer.
  • mabynack's avatar
    mabynack
    Explorer II
    Sep 21, 2016
    I found that it was easier to just change the whole rear end than to change gears. It's been several years since I did it, but I found a used rear-end in the junk yard for less than what the new gears and setup would have cost. I could change the whole thing by myself in an hour.
  • 1jeep's avatar
    1jeep
    Explorer II
    Sep 21, 2016
    gear noise form new gears would lead me to believe the person didn't set up the gears properly. It isn't a bolt in item, things such as the back lash and pinion depth must be set right or this will be the outcome. As for the PC, I could understand them needing to go in and edit the pc so it now knows the gearing, this would correct the speedo.
  • Calicajun's avatar
    Calicajun
    Explorer
    Sep 21, 2016
    Look into changing gears closely before having the work done.

    Tired having a the gears changed on a 2013 Tahoe from 3:08 to 3:42 gears. The shop tried seven times with six different sets of gears and could never get it to work right.

    The new gears would make a high pitch noise. I called GM and they stated that everything is tied into the computer and the computer would have to be changed out also.

    I was lucky because the shop refunded all of the money paid and put the Tahoe back to stock which ran great after putting the 3:08 back in the Tahoe.
  • romore's avatar
    romore
    Explorer II
    Sep 21, 2016
    With the gear change the engine would be turning just over 2300 rpm at 60mph. Mileage might suffer a bit but acceleration and hill climbing ability would be improved. Your truck as equipped really isn't capable of comfortably towing much more than a tent trailer, the 4.8 is marginal at best.

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