How to: Remove nylon driven gear from speedo shaft for gbox conversions etc

[RobST162]

I will give a quick overview of my the final solution here. Some of you may recall my older solution which involved creating a slightly longer key on the shaft to match the newwer box, but we found a great way (which most of you will probably be able to think of with a bit of common sense anyway)

The Problem. 1998 BEAMS LSD Box with electrical speedo arrangement needed to mate with my 1988 ST162 mechanical speedo setup.

First Solution: Create a modified key to sit between the gear and shaft and the pickup on the mechanical speedo cable. This did not work because the oil seal on the mechanical cable end was too high and the box leaked. We needed to change the gear.

Final Solution:
Step 1: Remove gear. I tried doing this with a vice here at home and failed. What I didn't think of was to head the shaft very hot with a heat gun and then using a press push the shaft slowly away from the gear. The hot shaft melts the nylon just where it touches and allows for removal.

Step 2: Install removed gear on 162 pickup shaft. This is just the reverse of step 1. Heat the recipient shaft, then use a lathe (or press if you don't have one) to push the new gear very accurately onto your desired shaft. The hot shaft will slowly melt the nylon where it contact and then set around the knurling (sp?) on the shaft. It's as good as the day it was made and now awaiting intstallation into my car.

Hope this maybe helps someone.

Using the press to push the heated shaft out of the gear.


Destination shaft top, old shaft with gear removed bottom.


The nylon gear comes off very cleanly!


Heating the shaft on our test case. It wasn't as well aligned as when we used the lath to ensure accuracy in alignment. With care you could still do this.

[88FOUR]

hey, ..was reading your solution to the electronic speedo, converted to mechenical...and was told by terry at road and track that i need to have my electronic speedo connected as well, or the ecu will no read it, and i will loose 60 percent of my power.

[RobST162]

well, the Gen 1 3SGE with the ST162 doesn't have any connection between the ECU and the speedo, so I don't think that applies

furthermore, my speedo on the GPA is on the blink, yet I don't notice a 60% decrease in power when it's messin' up