Originally Posted by only in a jeep cj
The speedometer is a set calibration from the factory and requires much know how to adjust it, but that is not the correct solution in your case. As said, the speedo gear in the transfercase is the solution. It is under where your cable screws in to the rear section. 1985 with a T5, you most likely have a 31 tooth gear and will need one a few teeth less so it spins a tad faster and bumps up the speedo.
I believe this same place sells a adapter that has different ratios. While more expensive ($65) they do work, its installed on the TC externally, the cable then screws into it. They do work well, I have 2. One of them has 40,xxx miles on it.
They are avaible in different ratios.
1957 WILLYS pickup, needs work.
1973 J 4000,
1978 CJ7 DD.
1979 CJ7 360, TH400/Quadratrac trail Jeep.
1980 CJ5 trail Jeep.
1983 CJ7 pretty weekend and sometimes to work Driver in the summer, My first rebuild, if the Q-trac and 5 are broke, this one is the one to take. its just as capable as the other 2, except nice paint.
1984 Grand Wagoneer, 1 ton axles, great 360/727, and a big a$& tree fell on it .
1989 YJ the CJ to YJ conversion.
2005 TJ Rubicon.
2011 Grand Cherokee Laredo 4x4, Mrs. LUCDOG's DD.
Lots of parts not for sale, i'm a hoarder.