Forum Discussion

gmcman's avatar
gmcman
Explorer
Apr 19, 2021

Question on changing legal GCWR

While looking for an 8.1 Burb, I come across some 3:73 models which have a factory GCWR of 16K. Since the only change to the GCWR of 19K with the 4:10 models was the gears, has anyone changed the gears to increase the legal GCWR? By doing this also with documentation changing the legal GCWR?

The GVWR is the same 8600 LBS with both axle ratios, only the GCWR changes.

I understand most agencies won't pay much attention to more than the tow vehicle GVWR, trailer GVWR, and tire ratings.

I'm only looking to maybe change the legal GCWR if it came down to this.

If anyone has gone through this successfully, please share your thoughts and experience.

Thanks.
Tow Vehicles
  • BurbMan's avatar
    BurbMan
    Explorer II
    Apr 19, 2021
    Yes the GCWR jumps from 16k to 19k because the tow rating jumps from 10,500 to 12,000 with the 4.10's. I wouldn't go higher than 4.10's because with the 4L80E 4-speed transmission you'll be screaming at highway speeds. IIRC, the next step after 4.10 is 4.56, I think the 4.30's is a Ford gear. Also anything higher requires a new housing I'm told, so between that and the GV overdrive you'd need to cruise comfortably, you'll have more invested in gears than the truck is worth.

    How much trailer are you looking to tow?
  • blt2ski's avatar
    blt2ski
    Moderator
    Apr 19, 2021
    If you're going to change out gears, go to a 4.33.
    You're looking at $2g per pumpkin, you'll get more take off power which you lack with the trans in that rig.

    Marty
  • JRscooby's avatar
    JRscooby
    Explorer II
    Apr 19, 2021
    In my state, you put passenger car plates on the 'burb. Then your only legal limit is tires. If the weight watcher sees you squatting real bad might stop you to look at them. With a RV, not likely to be heavy enough to be looked at.
  • dodge_guy's avatar
    dodge_guy
    Explorer II
    Apr 19, 2021
    That a performance number, no legality behind it, only if it’s still under warranty and you were towing more than the 3.73 rating, hen they could’ve denied coverage.

    I went from 3.73 on my V-10 Excursion to 4.30 (factory option). Best thing I did for towing.
  • MFL's avatar
    MFL
    Nomad II
    Apr 19, 2021
    Agree ^^^^GVWR is a manufacturers drive train rating, stating they will warranty your vehicle, if you stay within the amount your truck is designed for. You can change gearing, if you wish, and your drive train will be capable of handling the difference.

    Not a legal issue.

    Jerry
  • wing_zealot's avatar
    wing_zealot
    Explorer
    Apr 19, 2021
    The GCWR is just that, a "rating". There is nothing "legal" or "illegal" about it. If you want to change the gear so it tows better, go for it.

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