Speedometer gear for 3.42 rearend
#1
Speedometer gear for 3.42 rearend
I am having troubles finding a speedometer gear for my TH-350 Trans. Currently reading 75-80 when im going 60-65.
Anyone know of a site with data to find the correct part?
Anyone know of a site with data to find the correct part?
#7
Finding out the speedo drive gear size, should be easy as pulling out the driven gear housing, and checking gear color. Really depends on what axle you originally had vs the 3.42 now, as may need a new driven gear plug in housing as well. The Transmission Center site shows all of this. Note, the listed 700R4 parts are the same for non Chevy TH350's. I went from 2.41 axle on my car to 3.73's and had to change both gears when running a TH350. You'll need to pull the driveshaft, and unbolt the tailshaft housing to change the drive gear. When I switched to a 700R4, all gears were directly swapable. The 700R4 I used, had a Chevy bolt pattern, and needed an adapter plate to make it work.
#8
I think this may shed a little light on the subject
VERY GOOD Site for references, especially with the Speedo Gear calculations and ratios!! ....
Transmissioncenter.org mentioned above was helpful too!
Last edited by Slomega; July 24th, 2012 at 12:22 PM.
#10
Best place I've dealt with is Performance Automatic Transmission Center (PATC). They have everything for the speedometer gear, housings included.
http://www.transmissioncenter.net/sp...n_______va.htm
http://www.transmissioncenter.net/sp...n_______va.htm
#11
I faced this same issue a year ago. Got an adaptor so I did not have to change both drive and driven gears. Within a couple of MPH on the GPS now.
https://classicoldsmobile.com/forums...o-adapter.html
https://classicoldsmobile.com/forums...o-adapter.html
#13
Try here: http://www.speedometersolutions.com/
#14
Ah, there's a link I haven't seen yet. I visited most of the other sites other suggested on different forums. The TCI website and a couple others that sell trans parts. I'll give them a whirl. Thanks
#15
Supposedly there are 3 different housings, you need the correct one for the 43 tooth gear.
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delta881972
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February 26th, 2010 09:42 AM