BCM Community

Dear Friends,

I posted a long while back a question about my transmission. On the top of the tranny is stamped "Rockwell 166-09". I searched all over looking for info, and found it mentioned in several places, but no info.

Today I discovered several things. First, an awesome website with tons of free truck transmission manuals in PDF format:

http://www.globaltransmissionsupply.com/downloads.html (http://www.globaltransmissionsupply.com/downloads.html)

The second thing I discovered was a plate on the SIDE of my tranny with all kinds of data. From that plate, I discovered that my box is in fact a Rockwell RM135A2S006. So I was able to download the appropriate manual from the site above.

What I have not been able to figure out is my gear ratios. And one interesting thing in the manual is that there are two versions of the RM135A: One has a direct ninth gear, and the other an overdrive ninth gear. I would love to know my gear ratios! Can anybody help me with this info?

Thanks in advance!


 

.73...1.00...1.38...1.93...///...2.74...3.76...5.19...7.26...///...10.89.  This is only a guess, but kinda an educated one.  Hope this helps.  HB of CJ (old coot)

Thank you, sir! So I do have overdrive! That means I will get 15 miles per gallon: 7 mpg going, and 8 mpg coming!
;D

1.00...1.37...1.89...2.65...///...3.76...5.15...7.11...9.95...///...14.93.  This is only a guess based upon the likely steps of 37%...38%...40%...///...42%.../// and about ??...50%.  Your ratios may vary kinda maybe.  I do not know if you have an overdrive or direct transmission.  Best quess (again, kinda) would be you have a direct tranny.  Good luck.  How fast can you go and what is the rpm and tire size?  We can guess-a-mate back pedal from there.  HB of CJ