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Randall C
Randall C, ASE Master Tech
Category: Chevy
Satisfied Customers: 12831
Experience:  ASE Master, L1, 32 years, Diagnostic / Electrical Specialist
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1990 chevy 1500 4.3 th400 trans how do i find the rear gear ratio

Resolved Question:

i have a 1990 chevy 1500 4.3 th400 trans how do i find the rear gear ratio
Submitted: 6 years ago.
Category: Chevy
Expert:  Randall C replied 6 years ago.
Hello, My name isXXXXX will do my best to assist you with your question. Since we do not know what axle you have,, you need to look for the indentity marks on the axle at various locations shown. If yours is like the second picture, see if the ratio tag is still held by cover bolt on back of the rear. Once you get the numbers/letters off rear, lmk and i will pull the ratio charts and let you know

These vehicles use various rear axles. The axles can be identified by ring gear size in inches, by manufacture Saginaw (Corporate) or Dana and by the type of axle shaft used (semi-floating or full floating). Corporate axles include the 7 1/2, 7 5/8, 8 1/2, 8 5/8, 9 1/2, and 10 1/2 inch ring gear axles. Dana supplies a 11 inch ring-gear axle. The locking differential is supplied by Eaton.

The 7 5/8, 8 5/8-inch ring gear axle is semi floating with an alphanumeric broadcast code on the right front part of the axle housing. The Axle housing cover does not have a drain plug.

All corporate rear axles are identified by a broadcast code or part number on the right axle tube near the carrier. The rear axle identification code and manufacturer's code must be known before attempting to adjust or repair axle shafts or the rear axle case assembly. Rear axle ratio, differential type, manufacturer, and build date information is stamped on the right axle tube on the forward side. The first three digits indicate the rear axle ratio. The next digit indicates the axle assembly build source code: (C) Buffalo and (K) Canada. The next three digits indicate the day built, displayed in Julian Date form. The last digit indicates the shift: (1) First and (2) Second. Any reports made on rear axle assemblies must include the full code letters and build date numbers.

Dana Model 80, 11 Inch Ring Gear

All Dana Axles are identified by a part number and manufacturing date on the right axle tube, cover plate side. The model number is XXXXX on the carrier. The carrier does not have a drain plug

The Rockwell axle is identified by the model number on the carrier. This axle has a separate carrier, an overhung pinion, and incorporates disk brakes.


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