I have an open 9" rear in my '78 flareside, not sure what gears but I like them whatever they are. My question is how good does welding the spider gears to obtain posi do? Will the welds hold, what happens if they break, etc.? How much would most shops charge to do this?

 

Welding the spiders doesn't make a posi it completely locks the rearend. You will be chirping tires around every corner. If welded properly they should hold fine. If they break it could be anywhere from nothing to completely destroying the rear it just depends. I don't know if you will find a shop that will do this for you, it is usually a shadetree mechanic kinda thing.

 

The 9 inch is called "The poor man's quick change" because it is so easy to swap out.

You have to pull this thing apart no matter what you do.... Detroit lockers aren't free, but you will have something you can rely on, rather than worry about, or worse yet, have something that will push you into the ditch as a fully locked rear will do if you have the misfortune of hitting low traction in front/good traction in the rear in a corner.

Don't weld those spiders.....sell them to someone who needs an open diff.

Just a thought.

 

I'd go with a mini-spool if I were you. I got mine on e-bay for $28. The advantage is you can remove it if you don't like the street manners it has.

It's cheap and relatively easy to install, but it WILL change the handling of the truck.

K.

 

Since 9" carriers are cheap to find, and easy to swap, you could do the mini spool thing and keep your open diff as well.


You could have a ratio for every day of the week, come to think of it.

Oh heck, they're not THAT easy to change....

 

What's a mini-spool in relation to a true spool? Also..how does a spool differ from a locker?

You could probably go to a Junkyard and find yourself a Trak-Lok 9" running around with your same gears or something close (If you have 3.73...you could probably find some 3.55 or 4.10 to throw in and not notice alot of difference either way). Of else you could just get the parts needed out of a donor rear end and throw them in the one you have now. Or do as mentioned and get the other traction-related parts to put back there.

If this is a street rig...spider welding is a nono. And if its a trail rig you ought to have a locker or something anyways ^_^. Plus..you'll be chirping and wearing your tires more..and those aren't exactly cheap.

 

Saurian, a full spool replaces the stock open carrier, just as a Detroit or limited slip diff would. A mini spool goes inside the open carrier and replaces the spider gears of the open diff. "Lunchbox" lockers (EZ Locker, Quick Lok, LockRight) also go inside the open diff and replace the spider gears.

The difference between the lockers and the spool is: A spool permanently locks the axleshafts together under ALL circumstances, so there is NO wheelspeed differentiation for turning. The tires must 'scrub' around every turn. This is not a typical street driven application. It is mostly used for offroading and drag racing. There is also a "Lincoln locker" (named after Lincoln welding machines), which is when you weld the spider gears of an open diff together to get the same effect as a spool.

The Lincoln locker is not to be confused with an actual locking differential: A locking diff does allow for wheelspeed differentiation but also gives full traction to both tires under all conditions, even with one tire off the ground. It accomplishes this with a one-way ratcheting mechanism that allows the inside tire in a turn to remain locked to the driveshaft and the outside tire to spin faster, but not slower, than the inside tire.