Gear Ratio mismatched

Discussion in 'General Discussions' started by Walter Joy, Oct 22, 2016.

  1. Walter Joy

    Walter Joy Junior Member

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    My first ever thread, so I hope it's a good one. I'm a teenager who has a fair bit of knowledge of mechanics and cars, and has been gifted with a 1989 Dodge W250 that has been in the family since 1992. I have just started working on the truck this past week with my family in order to get it on the road for me to go to school and work. Today we decided to put some new RTV on the front differential because it seemed like it was leaking. When we took the cover off I found the tag, and discovered the front axle, a Spicer 44-8F 3500lb, has 3.54:1 gearing. Now I had remembered looking at the build sheet and seeing it was supposed to have 4.10:1 gears. So I checked the rear tag (Spicer 60HD 5800lb) and saw it had a 4.10 in it. Is there supposed to be that much of a difference between front and rear? The driveline is a 360 V8 (throttle body) with a 727 Torqueflite and an NPG241 transfer case. I have read other forums across the web but they only discuss axles that are .01 or so off, not .56. Thank you so much
     
  2. DaKing

    DaKing Senior Member

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    That is too much of a difference.

    Maybe one of the axles was replaced? Or maybe someone upgraded to 4:10's and did not change the tag?

    You can check by jacking up each axle, rotate a tire and count how many times the drive shaft turns. 1 full rotation of the tire, count turns of drive shaft.
     
  3. Walter Joy

    Walter Joy Junior Member

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    I will try that the next time we have the front jacked up (replacing the brakes now). The build sheet said it should have 4.10 and I assume it means front and rear. Just seems odd. The build sheet also specified I had 12x2.5 rear drums but when we measured them (after buying all the stuff for new 2.5 drums) they were 3 inch. So somewhere there are things not lining up
     
  4. 07MegaCabRam

    07MegaCabRam Senior Member

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    front and rear need to match.
     
  5. Walter Joy

    Walter Joy Junior Member

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    Yet the odd thing is it seems alright when in 4wd (or I think. The light doesn't come on so either it's blown or something else)
     
  6. Jimmy68

    Jimmy68 Senior Member

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    Take off your covers. Verify your gears. If you do not have a match set do not use 4x4 till you do. Be fine to drive and be fine to use 4x4 in the mud. Front will spin faster which actually will help. I'm talking deep mud, like a foot or more. Chances are as a daily driver your not abusing your truck like that anyway.
     
  7. Rustycowl69

    Rustycowl69 Senior Member

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    counting driveshaft revs has been kinda hit or miss for me, and tags can be swapped. But removing the covers and reading the numbers stamped on the ring gear or counting the teeth on the gears is foolproof.
     
  8. Walter Joy

    Walter Joy Junior Member

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    Thanks. I bet it just is a mismatched tag (probably from factory too. Who knows). As dad was saying, he's driven the truck 300 miles round trip in 4wd during snow once and it hasn't blown up. So I would expect it to have done so between 1989 and now
     
  9. crazzywolfie

    crazzywolfie Senior Member

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    the drums are the same for both 2.5 and 3 inch wide shoes. also since you are doing the brakes and lines this would be a good opportunity to swap to 3" shoes and the larger 1-1/8" bore wheel cylinders. both should cost about the same as the smaller parts.
     
  10. Walter Joy

    Walter Joy Junior Member

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    Next time around. Right now I just want to get the truck on the road again after 10 years of it being idle (to put it in perspective, 3 or 4 years ago we took it on the road and the odometer rolled to 44,000 miles. Today it sits at 44,035 miles.)
     

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