308 to 373 question

[DieselWarrior]

I had an 89 S-10 Blazer once, it had 308 gears. For it, in order to go to 373 or higher, you had to get a "special" R&P gearset. I think it was either thick or thin ring gear.

Is there any such silliness with the K5? I have 308 and wanting to go 373, thinking of just getting my axles geared, since they are in known good condition.

Andrew

 

[imiceman44]

I had an 89 S-10 Blazer once, it had 308 gears. For it, in order to go to 373 or higher, you had to get a "special" R&P gearset. I think it was either thick or thin ring gear.

Is there any such silliness with the K5? I have 308 and wanting to go 373, thinking of just getting my axles geared, since they are in known good condition.

Andrew

So what size tires are you running?
If you are not bigger than 32 I would leave them 308 gears.
I had 35" tires with my 308 and I got great mileage, but I did have a manual so I didn't worry about burning my tranny.
You have a th400 or 700R4?
If it was a military truck it has a th400 and I would just leave it.
If it's a 700R4 and you have big tires then yeah change the gears although it's cheaper to swap axles.
And by the way your axles can take 3.73 gears with no silyness, no thick gears or thin gears.

 

[4X4HIGH]

To answer your question, the carriers are the same for any gear from 2.73-5.57 so nothing special and no carrier needed.

 

[Big Ray]

the old 12 bolt truck axles had a cut off for ratios, I wanna say @ 3:42 or so


you could buy the thick gear sets for the higher (lower numerically) gears.

I have a Precsion Gear thick set 3:73 for a street truck project I was working on....@ 94 or so.....

 

[4X4HIGH]

Yes, the 12 bolt does have a carrier break, it is 3.07-3.42 then 3.73-4.56

 

[imiceman44]

Yes, the 12 bolt does have a carrier break, it is 3.07-3.42 then 3.73-4.56

That's weird because the 12 bolt never had 3.42 offered.
The 10 bolt however did have the 3.42 gear ratio as standard when it came out.

 

[4X4HIGH]

That's weird because the 12 bolt never had 3.42 offered.
The 10 bolt however did have the 3.42 gear ratio as standard when it came out.

Well, not sure where you got that info but it is wrong, I owned a factory 3.42 geared 12 bolt.

 

[DieselWarrior]

I just looked to verify, I have 10 bolts front and back.

So do I or do I not have a "universally standard carrier", or is there a 'split'?

1982 civilian K5 Blazer, 6.2L diesel, 700R4.

Thanks!
Andrew

 

[496truck]

To answer your question, the carriers are the same for any gear from 2.73-5.57 so nothing special and no carrier needed.

And when you go to order gears, they are for the 8.5" 10 bolt.

 

[DeviousK5]

Read what scott gave ya. On a 8.5ten bolt there is not a carrier break. Good to go-so to speak, it is a ten bolt after all LOL

Dont mean to sound like a dick either

 

[DieselWarrior]

Thanks to ALL for your kind help!

I am examining the possibility of a gear swap due to the fact, that the current axles are in great condition, and am hesitant to swap unsure/unknown condition axles and then be out of service for a while.

Again, thank you CK5 and members, you have always been of generous help!

Andrew

 

[tRustyK5]

Well, not sure where you got that info but it is wrong, I owned a factory 3.42 geared 12 bolt.

Yup, I just bolted up a 3.42 12 bolt under my truck. What I found weird was the ring was stamped with the actual ratio (3.42:1) instead of having pinion count and ring gear count stamped like all the 10's and 14's I've seen.

Rene

 

[79rustyk10]

the 12 bolts ive had have the tooth count stamped on the ring gear. maybe an aftermarket gear set?

 

[tRustyK5]

I kinda doubt it. The K5 they came from was the correct era ('78 with 12 bolt rear 10 bolt front, factory 4 gear truck) and I have the option tag from the glove box listing 3.42's as the optioned ratio, plus the G80 locking diff (gov bomb)


Rene