axle gear question

[Ronm909]

My step dad has a 70 blazer 4x4 that he is frame off restoring, prior owner made a mess of this truck, we believe the axles may have been swapped, the rear axle perches were welded on badly and rear leaf srings are different sizes, possible accident, anyway, we opened up both differentials and counted pinion and gear teeth and we came up with 2.70 for front and 2.60 for rear, this does not seem right. is my math wrong? both pinions have 16 teeth and front ring has 43 teeth rear ring has 41, any help??? did some one swap these axles or does the front axle have a lower gear by .10.

[Ronm909]

anyone please??

[1969K10]

You did the math right. I'd say someone swapped in a different axle for mud runs.
You need to get your gearing closer than they are.

[LONGHAIR]

You did the math right...but it doesn't match up to a known combination.

41-16 comes out to 2.56 which is ok....but it must have come from a later model truck, probably from the early 80s.

43-16 equals 2.68, but nothing like that exists AFAIK. It is far more likely that you miscounted something. 41-15= 2.73 which is another available combination. 43-14= 3.07 is another possibility.

You really don't have to physically count them though. The numbers are stamped right into the side of the ring gear itself.

As far as gear spread (difference between frt/rr) it depends upon a few things. The main factors are tire size and available traction. Both put more strain upon the entire drivetrain. I have seen as far as .25 run successfully. It was 5.38 front and 5.13 rear, but this was in a 3/4 ton truck that was used exclusively in mud (as far as in 4x4) rock crawling might be a different story?