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Technical Articles
| 09-01-2001 |
Going off of local PD speed checking radar, my speeds looked pretty good after putting on the 33" tires. I was almost dead-on at 45 mph. However, this method is not the most accurate. We all know that radar doesn't work.. especially if you have ever had a speeding ticket.
On our recent off-roading trip, I checked my speed against the others in the convoy, driving trucks with factory tires, and it was suprisingly off by 10-15 mph. While the difference is hardly noticed at low speeds, highway speeds appear to be well below actual speed. I checked the speedo gear chart, seen below, and figured I needed a 32 tooth gear. It only takes one day for the Parts/Service section of your dealer to order this baby, it is $18.
| SG26 |
SG27 |
SG27 |
SG28 |
SG28 |
SG29 |
| SG31 |
SG31 |
SG32 |
SG33 |
SG33 |
SG34 |
| SG32 |
SG32 |
SG33 |
SG34 |
SG34 |
SG35 |
| SG34 |
SG35 |
SG36 |
SG37 |
SG38 |
SG39 |
| SG36 |
SG37 |
SG37 |
SG38 |
N/A |
N/A |
Example: SG34 = speedo gear with 34 teeth
In order to figure out if your t-case requires the short (2.2") or the long (4.3") shaft gear we need to look at the connection. If you have the newer electronic type of connection at the t-case where the speedo gear is you will have the short shaft (1993-2000). If you have a cable type connection at the t-case where your speedo gear is you will have the long shaft (1987-1993). You may want to remove and measure it just to make sure.
Short shaft part numbers (1993-2000)
- 52067629 - 29 tooth
- 52067630 - 30 tooth
- 52067631 - 31 tooth
- 52067632 - 32 tooth
- 52067633 - 33 tooth
- 52067634 - 34 tooth
- 52067635 - 35 tooth
- 52067636 - 36 tooth
- 52067637 - 37 tooth
- 52067639 - 39 tooth
- 52067640 - 40 tooth
- 52067641 - 41 tooth
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Long shaft part numbers (1991-1993)
- 2538929 - 29 tooth
- 2538930 - 30 tooth
- 2538933 - 33 tooth
- 2538934 - 34 tooth
- 2538935 - 35 tooth
- 2538936 - 36 tooth
- 2538939 - 39 tooth
- 2538940 - 40 tooth
- 2538941 - 41 tooth
- 2538942 - 42 tooth
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Long shaft part numbers (1987-1990)
- 53001492 - 29 tooth
- 53001488 - 41 tooth
- J3212729 - 29 tooth
- J3212730 - 30 tooth
- J3212731 - 31 tooth
- J3212733 - 33 tooth
- J3212734 - 34 tooth
- J3212735 - 35 tooth
- J3212739 - 39 tooth
- J3212740 - 40 tooth
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- Mark the electrical connector going into the top, rear of the transfer case. This is for ease of reinstallation
- Remove the machine screw and retaining clip from the connector. Save this, it needs to be reused.
- Slide the connector and old speedo gear out of the transfer case.
- Pull the old speedo gear off of the speedogear adapter.
- Make sure that the index marker is aligned for your new gear, newer models will have this etched on the speedogear adaptor.
- Push the new speedo gear onto the adaptor.
- Insert the adaptor into the transfer case, lining up the mark made previously.
- Replace the retaining clip and machine screw.
- Go test your speed against a friend in a car.
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New gear from Mopar
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Removing the old speedo gear
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Old and new gears, clip and screw
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Reinstalling the adaptor into the Transfer Case
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