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A Trailer And An Overdrive.

Discussion in 'Early CJ5 and CJ6 Tech' started by Jw60, Oct 10, 2019.

  1. Jw60

    Jw60 That guy 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Correct me if I'm wrong... if your jeep has an Overdrive. you want to stay shifted in direct drive when towing a trailer and or offroad and or otherwise on the skinny break stuff pedal.

    I'm curious where the line would be for able to engage the Overdrive for say 2over on a hill.
    Empty m416 maybe?


    Background:
    Jeep has peppy v6 and 5.38s
    Trailers are a 1980s coleman popup at maybe 2000lbs with brakes that I want to get working, and a M416 with say 800lbs (figure 1500lbs total no brakes)
    I am about to let the 180hp jeep do all the truck stuff since the wife likes the 280hp family wagon.
     
  2. Rick Whitson

    Rick Whitson Detroit Area 2024 Sponsor 2022 Sponsor

    I learned about Overdrive the hard way. I had a Chevy Luv Truck Diesel, on my way to a job out of town, I had a good load in it, I was running in overdrive at 70 or so I smoked the transmission. It got so hot the teeth were gone, the OD gear looked like a pully. I was working it too hard in OD. I would not put a load on an Overdrive, I would only use OD if empty. Good Luck
     
  3. jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    i dont have an OD on my jeep, but this is what i was taught when towing trailers with newer vehicles, so i imagine a 60's jeep operates on the same mechanical ideals.
     
  4. Boyink

    Boyink Super Moderator Staff Member

    I'm not sure there's a hard and fast rule. V6/5.38s and empty Bantam or M416 and I don't think you'd ever have a problem running OD anywhere. Offroad you could still be using the OD to split-shift in different situations.

    Add 2K lbs load (which is more than I'd comfortably put behind an ECJ) and yea, probably a good idea to avoid the OD.

    Our '02 Chevy had a 8.1L and Alison 4spd. I never blocked out 4th gear when towing our fifth wheel.
     
  5. matt johnson

    matt johnson Caretaker of family Jeeps

    IMO I would NOT pull that much weight, OD or not. Sure you can pull it......but stopping it is a whole nother story. Do not put yourself or others at risk! Accident waiting to happen.
     
  6. Jw60

    Jw60 That guy 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Rest assured I am not toting a brakeless trailer with snowplow and all my spare parts. behind a jeep with 9" drums hardtop f-head and all my personal possessions from New York to Missouri again...
    Not like this:
    [​IMG]
    [​IMG]
    Or this:
    [​IMG]What not to tow by Joe with a jeep, on Flickr

    But like This:
    [​IMG]20190902_140419 by Joe with a jeep, on Flickr
    [​IMG]Raking
     
    Last edited: Oct 11, 2019
  7. Mike C

    Mike C Member

    That Allison would have been a 5 speed. Same as the one behind my '02 Duramax truck. And '01 ad '02 trucks did not have the ability to keep it out of OD. The shifter has 1, 2, 3, and D choices. The ONLY gear I would ever like to hold it in is 4th when towing heavy and two lane roads, and it's the only gear you can't hold. Obviously the engineers didn't ACTUALLY haul things. They added an OD lock out button in '03 and not too many years later a 6th gear.
     
  8. matt johnson

    matt johnson Caretaker of family Jeeps

    Towing a 2k popup with a Jeep weighing approx 235l lbs just does not make safe sense. I have 45 yrs towing experience from 800 lbs to 46000 lbs. Trailer brakes or not. Reconsider your options.
     
  9. colojeepguy

    colojeepguy Colorado Springs

    A V6 CJ5 weighs about 3000 lbs.
    Otherwise I agree with you 100%
     
  10. Jw60

    Jw60 That guy 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Looks like I should've double checked the camper's weight before posting.:oops:
    the camper is a Coleman Laramie as pictured which online is 995lbs empty and 1600lbs gross. Jeep isn't a lightweight and it does have disks on all 4. I thought the trailer was a lot heavier.:confused:
    Hopefully that makes more sense since I've already pulled this camper over the river and through the woods. It didn't feel crazy and stopping wasn't hard.
     
  11. jpflat2a

    jpflat2a what's that noise?

    Your Jeep as equipped will do fine. Only downshift would be on a long uphill grade...maybe.
    Folks, Jeep club members were pulling all kinds of house trailers behind their Jeeps in the 60's......
     
    Jrobz23 and garage gnome like this.
  12. garage gnome

    garage gnome ECJ5 welder

    I've towed my homemade jeep trailer with a hit and miss engine on the back. I used OD to split gears and it worked fine. Stock L head, T90 and 10" drums. Just drive smart and leave plenty of stopping distance.
     
  13. kenb

    kenb Cleverly disguised as a responsible adult

    If my poor math skills are correct 5.38 with an overdrive is still lower gearing than a 3.73 without an overdrive.
    I understand you can toast an automatic transmission trying to tow a heavy load in too high of a gear. Can someone explain why you can damage a manual doing so? I didn't think a manual gearbox would be so subject to overheating because of a heavy load.
    My towing experience towing with manuals is that the vehicle (really the engine) will tell you if you are in too high of a gear. If it starts knocking or feels like it's bogging down then it's time to downshift.
    As others have mentioned ability to safely control the vehicle and stop it are more important than how much it can pull.
     
    dozerjim likes this.
  14. Jw60

    Jw60 That guy 2024 Sponsor 2023 Sponsor 2022 Sponsor

    From what I found initially the manual Transmission will be fine. but the Overdrive unit added to the transfercase can overheat from high loads. being a planetary gearset with limited oil being slung into the pickup rather than an oil bath it heats up too much. Effectively it gives 4:10s from 5.38
     
  15. jpflat2a

    jpflat2a what's that noise?

    It might be of interest to know that the overdrive only burns up when it doesn't get sufficient lubrication.
    I don't know where false information gets its start.
    Some of us have over 40 years of driving Jeeps with overdrives and pulling trailers; using the overdrive in the sand dunes; using the over drive (a lot) in low range crawling situations.
    Take it from one of the folks with thousands of hours of use and seat time.
    The overdrive can handle it. (even reverse)
    Can you break it, yes you can if you abuse it.
     
    Keys5a and Bowbender like this.
  16. Jw60

    Jw60 That guy 2024 Sponsor 2023 Sponsor 2022 Sponsor

    It's in herm's instructions. The very last line.
    "Caution: This overdrive is not for use while towing or under a heavy load"
    Interestingly
    I don't see it in the original warn instructions.
    Warn Overdrive
     
    Last edited: Oct 12, 2019