Jump to content

Speedometer running slow


Sierra

Recommended Posts

  • Replies 3
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

If you bought it used the transmission may have been changed or possibly the rear end. The speedometer drive pinion in the transmission is mated to the rear axle and should be kept together. 

 

A '78 B-210 4 speed should have a 3.70 differential in it from the factory but earlier years and all automatics had 3.889. Possible an earlier 4 speed or an earlier differential was swapped. 

 

You should probably have a 17 tooth pinion gear inside for your year of B-210. If you have an 18 tooth then this is likely the problem and you are reading too slow.

 

If you have a 17 tooth pinion perhaps the rear end was changed to a 3.889 and your are now reading too fast.

Link to comment

The pinion would have to be removed. (10mm bolt holding a key that align the pinion)

Something like this... 00270018.jpgpre80pinionint0post80ransmods001.jpg

Pull straight out, trans oil may pour out so jack the back up and /or bark downhill. The plastic gears are color coded but count just in case.

 

The differential is more problematic. If removed the ratio is stamped on the crown gear. OR...

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.