Does anyone know the part number for these gears from GM? I'd like to see how much they are from gm parts direct. Thank you for the help.

 

Does anyone know of a site that may have this info?

 

You might check Scoggin-Dickey at www.sdpc2000.com

GM gets its gears from American Axle and Machine, who uses the brand name Motive. You can get the same gears from dozens of places. Thunder Racing, a sponsor on this page, sells them I believe; I often get stuff from here http://www.drivetrainspecialists.com...=28&cat=GM+7.5

Another source is http://www.racenet.net/ in the 93-97 or 98-02 F car sections.

I doubt GMPartsDirect would beat the prices at any of those places, and certainly not by more than $5 or so, seeing as how they're all so close anyway.

 

Just to clear things up. Motive and GM are not the same gears.

I just replaced a set of genuine GM 3.73 gears with a set of Motives. The Motive gears were manufactured in Italy . The GM gears were manufactured in the USA. Although American Axle may supply both GM and Motive gears, be aware that they come from two totally different foundaries.

The gear profile on Motives is different as well. GM gears are manufactured to provide quiet operation. GM specifies .005" to .009" backlash for new gears. My GM gears with 20K on them specced out at .009" backlash.

The Motive gears are cut a little differently. They require a lot more backlash. Motive calls for .008" to .012" for new gears. My set of Motives required .011" - .012" backlash to get a proper pattern.

Not a flame...just some additional info.

Edit: Spelling

 

Chickenman,
Which do you think is the better made gear for just some street crusing with the occasional blast around town?

 

IMHO, the Factory GM gears. They lasted me 8 years of very hard driving with never a wimper or the slightest noise until their last day.

Time will tell on the Motives...but I don't like the fact that:

1) After setting pinion depth to the numbers, .011" of pinion shim had to be removed to get the correct pattern. This was .005" less than the original shim stack. Either the Pinion depth number was stamped wrong ( We checked Pinion Depth three times ) or the machining on the gears was off. Original stack on GM gears was .025". We had to drop this to .020" on the Motives.

2) Backlash had to be set to maximum spec to get the correct pattern. .011" to .012" on new street gears is too much IMHO. But the gears require it. I set my GM's at .009" used. ( Originally the " experts" set them tighter than this but they were generating too much heat. They were .006" used which probably meant .004" to .005" new....Yikes!! )

3) The Motives seem to be running quiet now...but I would prefer that the pattern was a little lower, closer to the root of the Crown gear. That means adding more Pinion shim...but every time we did the pattern went screwy...no matter what backlash was run.

Edit: Spelling

 

Thank you so much!