ARareBreed Posted September 10, 2015 Share Posted September 10, 2015 I'm doing a direct swap from 1991 ax-15 2wd swap to a 1996 ax-15 4wd. I found the correct pilot bearing from the late model CJ and I have everything I need for the internal to external slave differences. The only thing I can't find on the internet is the difference between the speedo gears. I can visually see the plugs are different. Can anyone enlighten me? Link to comment Share on other sites More sharing options...
87MJTIM Posted September 10, 2015 Share Posted September 10, 2015 The speedo gear is in the tcase for the 4wd. You will need to get a gear based on the wheels you plan on running. The plugs may be diff by mechanical (cable) and electronic (wire). I don't know if the speedo parts from 2wd trans will swap in to a 4wd tcase. Link to comment Share on other sites More sharing options...
HOrnbrod Posted September 10, 2015 Share Posted September 10, 2015 The speedo gear in the 91 housing uses a longshaft gear and the 96 housing uses shortshaft gears. If the wheels are staying the same size and you keep the same ratio gears, you can simple keep the existing longshaft gear in the 96 as is and be fine. If you are going with bigger tires an/or a different gear ratio then you will need to size out a new shortshaft gear for the 96 from the tables here: http://gojeep.willyshotrod.com/HowtoSpeedoGears.htm All the speedometer gears are physically the same except they are color-coded for the different tooth counts, and will press on to either the short or long shafts. Link to comment Share on other sites More sharing options...
ARareBreed Posted September 11, 2015 Author Share Posted September 11, 2015 The speedo gear in the 91 housing uses a longshaft gear and the 96 housing uses shortshaft gears. If the wheels are staying the same size and you keep the same ratio gears, you can simple keep the existing longshaft gear in the 96 as is and be fine. If you are going with bigger tires an/or a different gear ratio then you will need to size out a new shortshaft gear for the 96 from the tables here: http://gojeep.willyshotrod.com/HowtoSpeedoGears.htm All the speedometer gears are physically the same except they are color-coded for the different tooth counts, and will press on to either the short or long shafts. I'm going from 28" tires/3.07 gears to 32" tires/4.10 gears. Link to comment Share on other sites More sharing options...
HOrnbrod Posted September 11, 2015 Share Posted September 11, 2015 Then you will be going from a 30T speedometer gear to a 36T speedometer gear. Link to comment Share on other sites More sharing options...
mikekaz1 Posted September 15, 2015 Share Posted September 15, 2015 also keep the housing to the truck. 1991 should use a 2 wire speedo and a 96 will use a 3 wire. just swap the 91 speedo assembly to the new one. it will fit. Link to comment Share on other sites More sharing options...
ARareBreed Posted September 15, 2015 Author Share Posted September 15, 2015 Thanks for the help guys, I'll update the thread. Link to comment Share on other sites More sharing options...
ARareBreed Posted May 16, 2016 Author Share Posted May 16, 2016 The 36 tooth give me about a 2mph faster speed on my speedometer than I am actually going. I'm running 4.11 gears on 255/75/R17 Cooper S/T MAXX. Link to comment Share on other sites More sharing options...
Eagle Posted May 18, 2016 Share Posted May 18, 2016 The 36 tooth give me about a 2mph faster speed on my speedometer than I am actually going. I'm running 4.11 gears on 255/75/R17 Cooper S/T MAXX. 2 MPH faster at what speed? If the tooth count is off, the speed difference will not be the same at all speeds. In actuality, +/- 2 MPH is about as close as the factory ever came anyway. They typically set them up to read slightly fast, so that people could blame speeding tickets on a speedometer that reads slower than the actual speed. Link to comment Share on other sites More sharing options...
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