What speedo gear do I need?

[Hart_Rod]

Originally Posted by tim_mc

Here's a good thread on pulling the tail housing and changing the drive gear:
http://67-72chevytrucks.com/vboard/s...d.php?t=462914

Good thread, however.... my tailshaft has something that looks a crushsleave on it. How the heck does that come off????!!!!

[Hart_Rod]

Originally Posted by Hart_Rod

Good thread, however.... my tailshaft has something that looks a crushsleave on it. How the heck does that come off????!!!!

I got the sleeve off with a little bit of tapping. I then took the output gear off. When I went to put the new output gear on, I noticed that there are two alignment holes in the output shaft. Which one is the correct one? It looks like it should be the most forward one. Suggestions?

[TBONE1964]

Here is the way to tell if your speedometer is out of cal.

Regardless of your tire size, gear ratio , etc, drive your truck on a measured mile.

If you drive a measured mile and your odometer either falls short or exceeds a mile, then your trans gears need changed.

If the odometer moves exactly one mile for the mile driven, the gears in the trans are correct for your combination.

If comparing your factory speedometer with gps, you will find the oe speedometer for these trucks are rarely on the money and need some calibration.

Hope this helps. I don’t know much about speedometer gears at the trans but know how to confirm if they are correct,

[TBONE1964]

Here is the way to tell if your speedometer is out of cal.

Regardless of your tire size, gear ratio , etc, drive your truck on a measured mile.

If you drive a measured mile and your odometer either falls short or exceeds a mile, then your trans gears need changed.

If the odometer moves exactly one mile for the mile driven, the gears in the trans are correct for your combination.

If comparing your factory speedometer with gps, you will find the oe speedometer for these trucks are rarely on the money and need some calibration.

Hope this helps. I don’t know much about speedometer gears at the trans but know how to confirm if they are correct,

[Hart_Rod]

Originally Posted by TBONE1964

Here is the way to tell if your speedometer is out of cal.

Regardless of your tire size, gear ratio , etc, drive your truck on a measured mile.

If you drive a measured mile and your odometer either falls short or exceeds a mile, then your trans gears need changed.

If the odometer moves exactly one mile for the mile driven, the gears in the trans are correct for your combination.

If comparing your factory speedometer with gps, you will find the oe speedometer for these trucks are rarely on the money and need some calibration.

Hope this helps. I don’t know much about speedometer gears at the trans but know how to confirm if they are correct,

Good info, Thanks!

Originally Posted by Hart_Rod

I got the sleeve off with a little bit of tapping. I then took the output gear off. When I went to put the new output gear on, I noticed that there are two alignment holes in the output shaft. Which one is the correct one? It looks like it should be the most forward one. Suggestions?

So I found a Youtube video from Monster Transmissions that explains why the clip needs to go in the most forward hole. I got everything put back together and the speedo is dead on!