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87 auto locking hubs vs. 86 manual

scott85

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Doing an axle swap between an 87 k5 and an 86 k10 (the 86 is the keeper). The 87 has auto hubs, and the 86 has manual ones. How do the auto hubs work? engage? disengage?
 
x2. Don't even consider the auto hubs. They are junk. BTDT, trusted them far to long, and I only used 4wd when hunting! Failed me AFTER they had been disassembled, cleaned, and tested.
 
Dont go with the autos they will fail when you need them the most. Or they can suddenly engage when you dont want them to.
Very Expensive to rebuild or replace.
Most everyone here ditches them for manual because of the problems the autos cause.
Converting to Manual hubs was the very first mod I did to my K5.
 
just take the old manual ones out of the old axle and put thm in ur new axle. Thet should just bolt in with a lil work. (like 10 min tops)
 
thanks for the replies. i appreciate it. how hard of a job to convert to manual is it?
 
OK for the auto lockers

1: unscrew the bolts/screws that hold to cover on then pull the cover off.
2: you will now see the internals, there will be a big retaining ring that holds the locking peice in use a set of Needile nose pliers to remove ring.
3: there might be a lil retaining ring on the end of the axle stud shaft pull that off to. (MIGHT NOT BE THERE)
4: pull internals out. DONE REMOVING AUTO HUBS.

For manuel hubs should be the same process above exsept the big retaining ring will have to be removed with 2 flatheads screw drivers.

install reverse order
 
scott85 said:
Doing an axle swap between an 87 k5 and an 86 k10 (the 86 is the keeper). The 87 has auto hubs, and the 86 has manual ones. How do the auto hubs work? engage? disengage?

They usually DO cause trouble, however - I've got a 87 diesel 3/4 ton Suburban with 520,000 miles on - and it still has the original auto-hubs - and they work great. It has seen a lot of towing and heavy use. My 94 1 ton Ford also has the original auto-hubs and has 300,000 miles on it. Ford uses the same make hubs as GM. They work great -when they are working - and are a pain in the a*s when they screw-up.

They are not weak - just prone to half-engaging when you don't want them to. I've put over a half a dozen on my 86 and 88 diesel Blazers - but never replaced with new. Used are easy to find since so many people remove them and convert to manual after the first problem. So, whenver they get removed, there is usually just one bad one, and still one good one.
According to GM, the problems with them are usually due to the wrong, or too much grease. I don't know, never tried to actually fix one. I have taken a few apart that gave me trouble -and all the parts inside looked like new - i.e. nothing worn or broken. Maybe the grease-story has some truth to it.

I wouldn't have the auto-hubs on a vehicle that rarely uses 4WD except for off-roading. But, I live on top of a mountain, and in the winter, I am needing 4WD, or and off, every day in the winter. And, I also need it to get into and out of my fields the rest of the year. I don't want to be getting out of the truck and locking my hubs everytime I want to come home - not do I want to drive all the time with the hubs locked. So, in my situation, I really like them.

Only draw-back is . . . you cannot shift into 4WD while moving. You have to be at a full stop, engage 4WD - then start moving and let them lock. To disengage, just put the transfercase into 2WD, and then backup a few feet.
 
johndem said:
Only draw-back is . . . you cannot shift into 4WD while moving. You have to be at a full stop, engage 4WD - then start moving and let them lock. To disengage, just put the transfercase into 2WD, and then backup a few feet.

The auto hubs on mine will engage on the go. All I do is clutch in and in neutral then throw the shifter lever into 4hi. I do the same to go out of 4hi into 2hi. But then the hubs are still locked and until I can go for maybe 10ft or so in reverse they stay locked, or sorta 1/2 locked.

But after about the first 10ft or so in 4x4 the hubs lock in strong and I can spin all 4 tires. Or at least all 3 tires (front axel is open)...
 
Yeah my old auto hubs were shift on the fly too. I could with my autos, and still can with my manuals hubs (if locked) shift from 2WD to 4 hi or back to 2wd at any speed below 55 MPH. As said, Had to back up to get them to disengage
 
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