Author Topic: Transmisson options  (Read 1748 times)

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  • Guest
Transmisson options
« on: June 02, 2008, 01:59:22 PM »

I recently purchased a 90 rocky and, like everyone here, love it.  I was wondering if a few of the more knowledgable rocky fanatics could tell me what transmission/t-case combo could bolt up to the 1.6L?  
Alternatively, i would like to reduce my fifth gear drive ratio down so that I am not turning 4K rpms at 75mph.  5th gear ratio is listed at .857 (or something similar).  Has anyone had a custom 5th gear made that is in the neighborhood of .65:1?
Thirdly, are there rear and front gear sets sold that are around 4.55 vs the stock ratios?

Thanks in advance...I will be contributing much to this forum and hopefully can document any mods I do to the Rocky!



  • Guest
Re:Transmisson options
« Reply #1 on: June 04, 2008, 03:27:52 PM »
Neen, where are you located? here in the U.S there is nothing that i know of.  4k at 75mph is pretty low for these smaller engines my geo tracker with stock tires turns an easy 4k or more at 75, keep in mind they are designed to be winding that fast from the factory that is where the power band is on most engines smaller than a 2L.  however with that being said one way to get less rpms at higher range is to go bigger tires say 31-33\'s as you will be lowering the \"final drive ratio by doing that\"  i dont have the numbers but in my tracker with 33\'s and in 5th gear i am running around 3500 about that speed(granted my speedo is off)but it says i am going 60mph and i am passing everyone.


  • Guest
Re:Transmisson options
« Reply #2 on: June 05, 2008, 08:15:57 AM »
I\'m located in Colorado.  Even though the ideal power band is right around 4K I don\'t believe Daihatsu had cruising at 75mph in mind when the gear ratio was selected/designed (since it was 1990 most hwy top speeds were 65 with a good portion of them still at 55).  Basically I believe I could get a few more mpg if I dropped the transmission ratio or the gear ratio down to around 3500 at 75mph.  

With your bigger tires on your tracker, did you notice a significant decrease in MPG?  I would like to step up to 30 x 9.5 x R15 but I don\'t want to loose my 26 mpg.  I am hoping with a little bigger meat under the Rock I would have a better final drive ratio for MPG and that it would offset the larger tires/loss of aerodynamics that are the result of a raised vehicle.

Since a lot of the parts for Daihatsu were sourced from Toyota, I was wondering if the gear set from a Toyota 8\" axle would work or if the 22R tranny would bolt up.