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Author Topic: gear help  (Read 620 times)

remingtongoose77

  • Single Axle Driver
  • *
  • Posts: 7
gear help
« on: April 09, 2017, 11:00:45 PM »

Hello,

I am brand new here and also brand new to the 3500hd. My truck is a 1996 with a 454 and 4L80e. It came with a flatbed and I took it off to build a custom one. My long term plan is to pull a 5th wheel camper.

Here is my question, does anyone have experience changing rear gears? I figure with my 4 speed auto and a 32 inch rear tire, my 4.62 rear gear will put me cruising at 65 mph at 2500 rpm. This sounds like 5 or 6 mpg.

Has anyone put in 4.10 gears? Can you verify if helped your mileage? I'm unsure of this gear change because if the new gears are too far off, the map measured engine load will unlock the converter or downshift.

Experienced help please?

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RPF207

  • 3500HD Driver
  • ****
  • Posts: 215
Re: gear help
« Reply #1 on: April 10, 2017, 07:57:11 PM »

Can't say I'm too experienced in the gear swap department but I hope someone can help. I would think that youd be ok. I don't think at 65 or 70mph with 4.10s that the truck will be doing much down shifting based on my 4l80e experience. and technically I believe you have a 4l85e which came in the HDs. Keep that in mind when doing any work to it
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1999 chevy HD 4x4 135.5" 6.5 nv4500 bw4470 Dana 70 HP 10 lug front

Due to recent budget cuts the light at the end of the tunnel has been turned off

Raymo

  • Global Moderator
  • 3500HD Driver
  • *****
  • Posts: 381
Re: gear help
« Reply #2 on: April 10, 2017, 08:52:52 PM »

I think it's a good compromise for losing a few rpm without hurting your bottom end.

I was running 4.10's in mine with a cummins and 5-speed, but am going to 4.56's with an Allison to push both ends of the spectrum. In my head it works out, having more grunt and two overdrive gears to get me close to where I was, if not lower.
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'94 3500-HD, Cummins, Getrag, NP205. Shortend rear frame with a Pickup Bed. Dana 60 front, stock 80 rear.

'03 2500-HD 8.1 and Allison