axles questions are now axle troubles...

Well... I guess it's a good thing that I'm about to buy a 14-bolt...

I had mentioned in a previous post that I hit the brakes and it made a crazy "Brrrrrr!!!!" noise accompanied by a wicked shimmy. Looking back, I braked around a turn when that happened.

Well today, around SEVERAL curves in the road I'd get the noise and vibration--without hitting the brakes!!

What's up?

FYI, my truck is a 1986 K5 Blazer, equipped with 10-bolt axles. It was originally a Police Bomb Squad truck. I had always assumed this thing had open diffs front and back, but recently I've read about the automatic lockers such as a Detroit and the noise associated with them locking and unlocking around turns.

Was a locker optional in 1986? Would the fact that it was a police truck make it likely to have had a locker ordered from the factory?

This is driving me insane. Thanks to those that replied concerning the noise and pointed toward the brakes. I did realize that my emergency brake lines in the back are junk and need replacing...

-Jon / jonrpick at yay hoo dot comm

Reply to
jonrpick
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There should be a RPO list in the glovebox. It will say something like: Do Not Remove This Label, or Service Parts Infromation. On there you should see a code G80 or GU80, denoting Locking Rear Diff. Charles

Reply to
Charles Bendig

It's got the GU80... Just checked it.

That would explain the craziness associated with driving it on snowy and icy roads. I couldn't control it or correct it--just had to come to a stop, and that took a while.

What's involved in removing the lock and converting it to an open diff while I'm getting my 14-bolt together?

BTW, I also realized that it has (yikes!) 3.08 gears. No wonder that thing won't maintain 80mph on the interstate. You can stay out of overdrive and lay on the gas, but it's a real exercise to not get passed by grannies in sedans while going uphill...embarrassing too :-(

If I can remove the lock and convert it to be open, I'll throw in something lower to make it more useful, like a 3.73 or 4.10 set.

Reply to
jonrpick

thing

The G80 dates to at least 73 and likely even earlier. I would strongly suggest you look for a 9.5 inch semi floater 14 bolt that was used in some HD 1/2 ton trucks and all LD 3/4 trucks. It is a diamond in the ruff and does not get its due. It is lighter that a 10.5 bolt nad has better housing clearnace of raod yet is quite strong and is basically in the same league as a D60 in strength and a lot stronger than a 10 bolt all the way around. It also has a lot more after market locker options than the 10.5 does because the 10.5 has a straddle mounted pinion which limits carrier design and size. Also, it usually comes with 6 lug hubs so no adaptors are needed to use your existing wheels. A friend of mine has a 1 ton van with a 9.5 inch 14 bolt and he has towed a big enclosed trailer with 5200lbs axles that weighs 7 to 9k usually (denpending on load in it) for years for work and with heavy tools in the extended van too (it weighs over 8 k normaly without trailer attached) and it now has 140k on it and rear axle is still quiet and solid.

Reply to
SnoMan

You need atleast 3.42 gears to torque up a hill. 3.08's were a econimy gear set. The taller the tire you go with the worse it will get.

As for the Gov-Lock EaToN diff, if you had a 8&1/2 rear I would straight trade you for a 14 bolt open carrier. Any Gov-Lock is a beer fix away from being a real locker.

Charles

Reply to
Charles Bendig

You mean you'd like to get rid of a 14-bolt and get a 10-bolt?

If that's what you're saying and you've got a 14 bolt, where are you?

-JP

Reply to
Jon Pickens

btw, I did run the numbers through the calculator on Randy's Ring & Pinion's website...

With my 3.08 gears, 31" tires, and 700R4 tranny, I'd be pulling 1402RPM at 60mph instead of the recommended 1800-2800RPM for a small block V8.

The same numbers with 4.10 gears show 1866RPM at the same speed.

That explains a lot about the way the truck performs...

Reply to
Jon Pickens

I sell used parts all the time. Axles come and go, nine inch fords, dana 30's, 44's, dana 60 rears, even sold a dana 60 front.

I might have a 14 bolt open in inventory. As they are Box-Truck/Cut-a-way Van rear ends.

As for 10 bolt rears. I only like the 8&1/2 old Chevelle rears. They are perfect for S-10 rears. Cirtant years have the right width for the desired track width.

Charles

Reply to
Charles Bendig

Where are you located at???

Reply to
Jon Pickens
.

Where is the info on this?

Al

Reply to
Big Al

jon: BTW, I also realized that it has (yikes!) 3.08 gears. No wonder that thing won't maintain 80mph on the interstate. You can stay out of overdrive and lay on the gas, but it's a real exercise to not get passed by grannies in sedans while going uphill...embarrassing too :-(

GC:

3.08... My '86 has 2.73!!! When it goes into overdrive, you think 4 cylinders dropped out. I'm going with 3.73 gears, and adding an additional "snorkel" to the breather... that should add some "go juice"!
Reply to
GC

Outside of Dayton Ohio.

Reply to
Charles Bendig

If you look at the Eaton website about Gov-Locks it describes how they work. From there you can figure out your beer fix to keep them engauged.

A Beer Fix is something a Mechanic does to his or her own car or truck, that they won't do to a customers. Charles

Reply to
Charles Bendig

Well if I were to get a 14 bolt from you how much would shipping to Atlanta, GA be?

Reply to
Jon Pickens
2.73! Wow... Yeah, I swapped a very tired 305 with a blown head gasket for a new 290hp 350ci crate motor. You'd think the difference would be amazing, but there was very little performance gain.

Part of it is engine tuning, but I know those gears aren't helping at all. It runs like it's got a straight 6.

BTW, how difficult is changing the speedo gear to compensate for the lower ratio axles?

Reply to
Jon Pickens

I have never rigged a GovLoc not to work but it would not be to hard to swap out to a standard carrier when you regear (front and rear axle). At very least you could likely sell your old locker to someone but I would not waste the time regearing it or changing diff id I planned to swap rear axles out. When you swap out, that id the time to regear. 3.73, 4.10 and 4.56 and availbile for 10 bolt and both style

14 bolts (9.5 and 10.5) so it is just a question of desided what you want to do but I would suggest and least a 4.10 because with that ratio in OD it about 2.90 to one over all so performance in OD with 4.10 will be less than what you are getting in drive now with 3.08?s. With this in mind, 4.56?s might be better because in OD it would be a effective 3.20 final drive ratio so OD would be a little better than drive currently is.
Reply to
SnoMan

Guess again, a 3.42 is not much better than a 3.08 in a truck with OD. Neither will pull OD on any kind or grade. Throw in big tires and it is even worse. A 3.73 if the bare minimum that should be in a big 4x4 in the real world with a small block engine on OD. this bussiness about 3.42 giving better MPG is pure BS because in my 89 4x4 burb it has 3.73?s with 29?s and I have gotten as high as 19mpg on hiway if I stay at or under 65 and in the 17?s if I run 70 to 75 and it will pull OD on most grades too even with A/C on and a load in burb. I ran 31?s for several years on it but OD performance was lacking so I went back to 29?s several years ago and glad I did. If I ever go bacl to 31?s or so again it will have 4.10?s in it because I detest a 4x4 that is a slug in OD.

Also the GovLoc in a 10 bolt is a POS and not very reliable or strong because of it limited carrier size vs tires size on axles. The GovLoc in the 9.5 and 10.5 14 bolt is a lot stronger and longer lasting too. Actually there is not much difference in strength between the 9.5 and

10.5 GovLoc units because while the 10.5 is bigger in theory, its carrier diameter is limited by the fact that it has a straddle mounted pinion while the 9.5 does not suffer from this. So many people upgrade their 1/2 ton axle to the 10.5 14 bolt axle when the 9.5 will do just fine and it prety bullet proof up to 38?s or 40?s, even with a true locker and there are a lot of after market selectable lockers that are avalible for the 9.5 that cannot be had with the 10.5 because of design limitations. THe 9.5 is with is 6 lug hubs and approx 5500lbs capacity is a excellant upgrade for a 1/2 ton truck
Reply to
SnoMan

Yes it does and you cannotuse the range of 1800 to 2800 @ 60 for a small block as a benchmark because while a low drag car might do well with a 1700 or 1800 RPM crusie and big draggy 4x4 with a big lift and big tires needs more than 1800 RPM to cruise well at 60 with good power for hills too. It needs more like at least 2200 to 2300 RPM at that speed or more yet depending on vehical drag and load.

Reply to
SnoMan

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