Speedometer Re-Gearing
Your Jeep Grand Cherokee
After you get use to the larger tires or new gears that you have added to your lifted rig, it is time for the next upgrade. This just might be the least expensive and easiest upgrade you ever do to your vehicle. It is time to change that stock speedometer gear and make your computer and the local law enforcement officers happier. It is probably more important to your computer, that your speedometer gear match's your ring & pinion gears and tires Don't get me wrong you are not doing any known damage by running the wrong gear. You just won't get accurate information from your on board information center. For a mere $20 and if you are mechanically challenged 15 minutes of your valuable time, you can have your rig back to accurate readings again. Visit your local Mopar dealer or visit one of our online dealers for your speedometer gear listed in the chart below.
Speedometer Gears with Mopar Part Numbers
| 52067629 - 29 tooth Speedo gear | 52067633 - 33 tooth Speedo gear | 52067637 - 37 tooth Speedo gear | 52067641 - 41 tooth Speedo gear |
| 52067630 - 30 tooth Speedo gear | 52067634 - 34 tooth Speedo gear | 52067638 - 38 tooth Speedo gear | 52067642 - 42 tooth Speedo gear |
| 52067631 - 31 tooth Speedo gear | 52067635 - 35 tooth Speedo gear | 52067639 - 39 tooth Speedo gear | 52067643 - 43 tooth Speedo gear |
| 52067632 - 32 tooth Speedo gear | 52067636 - 36 tooth Speedo gear | 52067640 - 40 tooth Speedo gear |
| Tire Size> | 38" | 37" | 36" | 35" | 33" | 32" | 31" | 30" |
| R& P | ||||||||
| 4.88 | SG36 | SG37 | SG38 | SG39 | SG41 | SG43 | SG44 | SG46 |
| 4.56 | SG34 | SG35 | SG36 | SG37 | SG39 | SG40 | SG42 | SG43 |
| 4.11 | SG31 | SG32 | SG33 | SG34 | SG36 | SG37 | SG38 | SG40 |
| 3.73 | SG27 | SG28 | SG28 | SG29 | SG31 | SG32 | SG33 | SG34 |
Example: SG26 = Speedo gear with 26 teeth
Photos and instructions are compliments of Chet Szymecki
First step is to go to the driver's side of your Jeep and crawl under there. You will easily locate the rear driveshaft that connects the transfer case to the rear axle. Now the gear that we will be changing is in the transfer case. You will see a wire loom that plugs into the rear upper part of the transfer case - this wire loom feeds the vehicles computer the rotational speed of the output shaft and that, along with other information, is used to compute your speed.
There is only bolt that we need to remove along with the retaining tab that holds the connection in place.
Now pay attention to how the plug is oriented prior to removing it - you may wish to mark it right now for proper positioning when re-installing. This is not critical for the gears or other internal parts - it will make it easier to re-install the mounting tab and screw. Now wiggle the plug nice and easy while pulling and the whole assembly should pop right out.
The stock (orange in this case) Speedo gear can be removed with a firm tug.
The new gear will be installed with the metal end first. Make sure the part is seated all the way prior to re-installation. A solid push should be all that is necessary to install your new gear. Now we must rotate the speedometer adapter so the different size (new) gear will engage properly.
You will notice the index number location markings on the adapter. Find which index your new Speedo gear falls into and rotate the adapter until that index is in the six-o'clock position. The rotation of the adapter is a cam type of action and will bring the internal gears into contact. The rest of the installation is just the reverse order of the steps that we have already taken. Now you are done and your Speedo is right on the mark.
Note: On some early transfer cases (ex. NP242) the index number location markings are actually engraved around the speedometer adapter hole on the transfer case, and not the adapter itself, which just has an arrow to be aligned with one of the marks.
Note: This chart only works for the newer (post 1987) transfer cases NP/NVG231, NP/NVG 242, and NP/NVG249 - not the NP207 or NP229.