I'm probably gonna buy an '84 parts truck. The guy says there are detriots front and rear. The price is so good I'm thinking he just has welded diffs in there..

How can I tell the difference between a welded diff and a locked diff without pulling the diff??

-Scerb

jack one wheel up and try to spin it. If you cant (because the other is attached via welding) it probably isnt a detroit. If you can spin that wheel and the other doesnt its not welded. To make sure you have a locker in there still have one wheel in the air and turn the drivshaft. If you can turn the driveshaft and only the wheel in the air spins, you dont have a locker in there.

Hopefully i explained this correctly!

Ok cool. Thats what I was thinking I just wasn't sure if you could get the locker to rachet by just jacking up one tire. Thanks!

This isn't really related to my question but I thought it was funny..

I went there to buy the truck and well,, the guy was full of crap. I asked if I could use his jack to test for the locker.. (trucks just outside his garage). He says "no my jacks don't leave the garage"

Well if you see his shop you know he doesn't care at all about his tools. I say "so how do I know theres actually a locker in the diff..?"
"well its actually an old style detriot, it wont rachet."
"so its a spool?"
"no it has clutches."

blah blah i figured the truck was worth $400 for axles/motor ect. I offer him 400 cash right then and there.

"nope im not taking anything less than 500"
"well im not spending moren 400 on a parts truck"
"well just the 4spd tranny is worth that.."
"HUH!? i got four or five 5spd's in my backyard.."
"well this truck also has 4.88's from the factory" (its an 1980 pickup.)
at that point I said "well, ill cya later then." and got in my truck.

the kicker, as I was about to start my truck: "thats ok.. I'm putting these axles in my jeep next week"

I wonder if he knows Jeeps are driver's side drop... <img src="/forums/images/graemlins/lol.gif" alt="" />

But ya, thats my pathetic scumbag story.. should be a good laugh for ya.. <img src="/forums/images/graemlins/rolleyes.gif" alt="" /> Do these "old style" detriot lockers with clutches actually exist??

-Scerb

haha jared. i shoulda gone with you dammit.

or wait. you should tell me where it is. ill go look at it. lol.

well ya know if you put the jack under the diff or center of the axle for the front both wheels will be in the air and it is alot easy to tell exactlly what there is in the diff and you only have to spin the tire once-ish

spin one tire, doesn't matter what side, and if the other wheel spins the opposite direction that is an open diff.

if the wheel spins the same try spining the primary tire the opposit direction, with out jerking, and if the other wheel stays spinning the same dirretion as before you have a locker, most likely you will hear or feel the ratchet. if the ratchet does catch it will have more play than a spool or weld if you keep spinning the tire easy one way than the other the ratchet will start ratcheting.

if it is a question between welded or an actual spool there obviously will not be any ratcheting and the secondary tire will always spin the same direction as the primary. the diffrence between welded and spool is a spool will have about a 1/4 turn "slop" between each tire, welded will be very jerky.

For the LSD or possi, when you spin the primary it will have the same reaction as an open diff, but when you hold one tire and spin the driveshaft a couple times you should not be able to hold the tire from spinning, and both tires will spin the same direction. that one is tricky to do, but very rarly is there a LSD in a truck axle, unless you are spify and put one from a supra in.


As far as the "older detroit's having cluth packs" depends on the cold hard facts. A locker is a locker, a LSD is an LSD, a welded is a ...well you get the point. So if it was a "detroit locker" than it is a locker and does not have clutch packs, from what i have read and researched that is how it has always been. The one thing i can remember reading is that a LSD and possi-trac are not the same. Both have clutch packs, yes, but an LSD is not nearly as tight as a possi. That and i have never heard of a detroit LSD or possi.

be hey i could be wrong....

i always get a kick out of looking for a car that i know more about than the owner, the best was when a guy told me that a 91 pickup has full time 4wd and a locking diff. i drove it and he said put it in 4wd when i turned on CONCRETE he said you hear that grinding clunking noise "thats the locker kicking in....well i taught that guy a valuable lesson that day. a week later he listed the transfer case being defective...haha...another truck i looked at had a horrible missfire, the guy said he coouldnt figure it out and i knew the problem the whole time as soon as i looked at it i offered him 600 bucks fixed the misrouted vacuum line and drove it home on a 200 mile trip, then that was my 5 speed swap donor!