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I am new at this so bare with me. I have a 86 k10 truck that I am rebuilding.
I bought it with no motor and with a 400 turbo transmission. It has 2.73 gearing in the axles, my question is does the transmission gearing affect the gearing I should put in the rear end?
I have been told that 2.73 gearing is not to good for a 4x4. I was going to put 4.11 because of the size wheel and tire i am going to put on.
Any help would be great.
 

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A T350 and T400 as well as any of the four speed manual transmissions available at the time all have 1:1 final drive ratios so they won't have any effect. However, a T350 does have a slightly lower 1st and 2nd gear than the T400 does. The T350 has a 2.52 first, 1.52 second and 1:1 third whereas a T400s gearing is 2.48, 1.48, 1:1. The SM465 four speed is 6.55, 3.58, 1.70 and 1:1.

What size tire and engine are you planning on running?
 

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4x4 truckster said:
I am new at this so bare with me. I have a 86 k10 truck that I am rebuilding.
I bought it with no motor and with a 400 turbo transmission. It has 2.73 gearing in the axles, my question is does the transmission gearing affect the gearing I should put in the rear end?
I have been told that 2.73 gearing is not to good for a 4x4. I was going to put 4.11 because of the size wheel and tire i am going to put on.
Any help would be great.

IF the truck is setup for a t-400 trans to the transfer case , you will need to use the t-400. No other trans simply "bolts in" ... there are shaft size differences from t-400 to a t-350.

The gear ratio difference from a t-400 to a t-350 is not something to worry about...... both trans are 1-1 in 3rd gear as posted earlier.

a 4.10 gear would be better if a large diameter tire is use on the truck.

:cool:
 

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Blazin72 said:
My question is this, did a previous owner install a T400 in it? Otherwise I thought half ton pickups came with the T350?
Actually with a 1986 year as posted..... there is a good chance it was a 700r4 trans in it.

Mayb a conversion to a t-400 trans with a special output shaft in the t-400 and an adapter?
 
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