14-bolt semi-float vs. 14 bolt full floater:

[vandelay industries]

(NOTE: i am looking for the right tow vehicle and want to do it right, and thus i'm asking a lot of basic questions, so please bear with me.)

When did Chevy stop equipping the suburban with the 10.5" Full-floating 14 bolt diff in 3/4 suburbans (and i'm assuming in 3/4 ton trucks) as standard equipment?

Could you still get a Full-floater as an option after the change?

 

[vandelay industries]

Update:
i heard/read that you could always get a full floater IF the suburban had a big-block and was 2WD, which is fine.

 

[obijuank5]

Big motors got em. Us border patrol burbs down here got em too and they are 4x4.

 

[dyeager535]

Update:
i heard/read that you could always get a full floater IF the suburban had a big-block and was 2WD, which is fine.

Pretty sure it was GVWR driven, not engine. Any engine in a one ton, it was going to get a 14FF, period.

Light 3/4 would be 14SF, heavy would be FF.

I want to think the break was somewhere around 8200lbs.

 

[MTBLAZER89]

Update:
i heard/read that you could always get a full floater IF the suburban had a big-block and was 2WD, which is fine.

This is correct according to GM documents for 81-91.

81+ 20 series (3/4 ton) rigs got the smaller 9.5" semi float 14 bolt UNLESS it came with the 454 which was only available in C/R (2wd)s. All 73-80 3/4 tons got the FF.

 

[dyeager535]

Semantics, could you get a low gvwr '82+ 3/4 with 454?

 

[MTBLAZER89]

Semantics, could you get a low gvwr '82+ 3/4 with 454?

A C20 sure. A K20 no.

 

[dyeager535]

I just looked it up in the brochure I have for 1986 C/K's, Dremu's page will probably clue us in to other years.

In 1986 you could get a C20 with 454, but only two: one specified as an "HD" C20, with a specific RPO, C6P. That RPO/GVWR (8600lbs) was standard with the 292, and could be optioned with the 350 or 454. C6P therefore got a 14FF. The second was the C20 bonus cab. That had no optional GVWR, it was 8600lbs w/14FF regardless of engine. If it was a "standard" C20, 14SF.

 

[MTBLAZER89]

C20 crews got 1 ton stuff regardless. They were an exception. They also have 1 ton spring hangers with a 40.5" spacing and the same frame as a C30.

 

[MTBLAZER89]

GM denotes the 454 as the factor to get a 14BFF. Their documents show that even a C6P 20 series came with a SF 14 bolt (6000 lb capacity) rear axle.

 

[dyeager535]

Interesting, that chart is different than the 1986. Not massively, but it's different. GVWR's are different in some instances, but the big difference is they left out the lines denoting 14SF and 14FF on the '86 brochure. It just says semi or full, but no line to denote where they stop and start. The way they line up makes it look like they line up with GVWR, not engine, but the note is there for the 454/FF, albeit in a different spot, that solidifies it.

Applying those lines to the chart in the 1986, it's much more clear. The K20 CP6's (higher GVWR) got the FF without a 454 , but a C20 always got the SF, unless it was a 454. That makes about zero sense.

Now I'm curious what they did with the 1987 brochure, since IMO it looks like they screwed the 1986 one up! Or intentional...