mci 102c3 axle ratio Id help

oldfordlover36 · July 28, 2014, 04:03:25 PM

I have a 1993 mci 102c3 with an auto transmission and wondering how I can tell the rear axle ratio. The tag on the rear end just has a serial number and a build date no ratio listed. I looked on rockwell/meritorious website and my number dosent match any of their listed formats to decipher the ratio. Any ideas?

robertglines1 · July 28, 2014, 04:42:50 PM

ck end of pinion shaft.

luvrbus · July 28, 2014, 04:53:00 PM

Robert is correct it is stamped on the pinon shaft,it would help if we knew what engine and transmission the bus has,the 3:36 was standard for the 6v92 and 740 Allison the 3:70 was a option

sledhead · July 28, 2014, 05:07:29 PM

on my 1990 mci 102c with a 6v92ta and ht 740 auto it is 333

dave

lostagain · July 28, 2014, 05:25:51 PM

I think mine is a 3.36. 6V92 and Allison 740 on my 5C. But yea, it is stamped on the end of the pinion shaft.

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oldfordlover36 · July 28, 2014, 06:39:16 PM

I apoligise it has a l10 cummins and a ht740. The ecm went south and I need to tell the programmer the ratio. I will look on the pinion u guys are the best thanks and Robert I love your prevost project!

luvrbus · July 28, 2014, 07:14:36 PM

Only problem with finding the ratio on the pinion sometimes you need to remove the yoke to see it, if all else fails jack it up and count the revolutions

TomC · July 28, 2014, 09:32:31 PM

If you have a GPS, and tachometer, you could just note the rpm's at 60mph then look up your tire size as to how many revs per mile it turns. For instance, at 60mph, if you have 11R-24.5 that turn 476rpm and the engine is turning 1585rpm, then divide 1585 by 476 and you come up with 3.33. Or you can lift up one tire and count the drive shaft revolutions. If only one wheel is up, it will be double. Good Luck, TomC

blue_goose · July 29, 2014, 11:42:45 AM

If you have a tack check rpm and mph. My 102C3 had a 3.36. I have a good set of gears for a 3.36 if you need them.

Jack

oldfordlover36 · July 29, 2014, 08:28:54 PM

Went to look at the pinion and found another label covered in grease right under it and said 3.21 gear ratio thanks for all the help! I will get a build thread going one of these days when I get a chance to show u all what I'm doing thanks again.
Tyson