Destroyed my 3.70 Equi-Loc

[JimNolan]

Guys,
   I was setting the Secondary's on my 4V this morning and it tore out my differential. I was trying different secondary springs to see if I could get the secondarys to open and each time I tried something different I'd go out and run it through the first three gears with my foot on the floor. A lot of tire squealling but what the heck. Well, I figured out what was wrong with my 4V. The gas pedal throw wasn't enough to take the mechanical lock off the secondary's so the secondarys couldn't kick in with vacuum. I fixed that. I increased the throw on the linkage and went out and tried it again. I always start my car off from a roll because the tires will go up in smoke if I nail it from a dead stop. I let it roll out at little and nailed it. This time instead of the tires squealling a little, the tires dug in. The front of the car went up and I could tell I was in for a ride different from the previous runs. Sure enough it was different. About the time the front end stabalized where you could tell it was going to stay I heard a big bang. The motor raced and I shifted into second and let out on the clutch. The car wasn't pulling itself. I coasted about an 1/4 of a mile, up a little hill and into a driveway on the hill. I coasted a quarter mile and up a little hill from that launch. What got me it didn't break when I nailed it. It waited until I was almost ready to shift into second. Oh yes, I found out my car will pull 5000 rpm out of a couple 54 primary jets. If I get it fixed I'll shift at 4800 though. The pressure of my back against the seat started lightning up around 4800. Anyway, I got out of the car, left the motor running in 1st gear and climbed under the car. The drive shaft was turning but the wheels weren't.
  You may ask yourself, why would he go out and deliberately tear up his car. Well, James can tell you I had it on the track at Gulfport and if I'm challenged on the highway I'll end up acting like a kid again. Better it happen a 1/4 mile from home than in Gulfport. It was a good Equi-loc while it lasted, now I want a differential that will take about 450 lbs of engine torque if I'm in Gulfport.
    You guys that have drag raced and tried to tear up your cars time and time again, will a Trac-Loc fit my needs. Jim   

[JPotter57]

Get a Detroit Locker Jim, you wont regret it.  You wont break it.  Trust me, its the only way to fly.

[JimNolan]

James,
   I always thought this was a race only differential. I looked at Just-Rear-Ends website and they don't look any different from a Tru-Trac except a couple hundred bucks more. Will I be happy cruising with this differential as well as being assured it won't come apart. I bought a Tru-Trac from just-rear-ends and they were about the same price as everyone else. Have you got a source you like that have good prices. Jim

[lowrider]

I've purposely stayed away from putting any type posi unit in my car because I would end up telling the same type story on my car. I know me. But if I did my 1st choice would be the Detroit Locker.

[Ford Blue blood]

What James said!  They can be a pain on the street (funny noises, tire draging on light acceleration while making a turn) but they will hook and last forever!

[JimNolan]

Guys,
   Took the pig out of the poke today. I pulled the drivers side axle and it didn't have any splines on it and it was 1 3/4" too short. Wah La, maybe I'm lucky. Took the passenger side axle out and it looked just fine. Got a magnet and pulled the end of the axle out of the differential but dropped it before I could get it out of the housing. Soooooo, out comes the pig. The gears are great, no play to speak of and the grease was clean. These axles are the old tapered shaft axles but it broke in the big section right where the spline starts. Pig is good but I'm adding more power to the engine this winter.
   Now for a replacement. After tons of reading reguarding the Detroit Locker I determined from the people that own them that it's not intended for what I want out of a differential. I explained to Eaton how I used the car and they suggested I stay away from the Locker. It's the best differential for staight ahead acceleration and durability while drag racing but the side effects would overshadow the benifits because most of my driving is cruising, shows and trips. They suggested the Tru-Trac, not the Trac-Loc like I bought for the Galaxie. They said with street tires my car couldn't hurt a Tru-Trac and I'd never know it was a posi-traction until I wanted to use it as such.
   That's it. Time to add to the red and white money pit. Jim

[JPotter57]

Good news on the diff...now, upgrade to some 31 spline Moser axles...no more breakage.  Thats what is going in mine.  By the way, NASCAR rides use Detroit Locker too..  I had one in my last 57, it did clunk a bit going around corners, but that was just the ratcheting mechanism allowing the outside wheel to unlock.  Its not anything I couldnt live with.  My dad has a 28 spline DL in his Falcon ragtop and its not kverly iffensive in it, makes that cutesy little car sound.manly, lol.  If you keep the limited slip, upgrade the side gears and axles to 31 spline if you plan on shifting at better than 4000.  28 splines are cool for knocking around with an automatic or a smallblock, but a stout FE with a manual and a low gear will kill it...just my .02.
Oh yeah, mine has a full spool and 4.56 gears, for now at least, lol....

[57AGIN]

Jim:

While I agree with the rest of the guys about the bullet-proofness of the Detroit-Locker, I've had good results with the Eaton posi in my 57 and it doesn't have the ratcheting around corners issue.  I, too have upgraded the axles to 31 spline Strange axles, definitely a good idea for the occasional drag strip tour. 

By-the-way, was the failure you experienced with the equa-loc or the 3:70 gears themselves?

Bob
57 AGIN

[JimNolan]

Bob,
  The equi-loc is OK. The differential held. It was the axle. It broke right at the place where the teeth on the spline ends. 1 3/4" from the end. The guy at Just rear ends said the Equi-loc was weak and had just TWO somethings that held it together. He said the Trac-loc had four so even a Trac-loc was twice as strong as the Equi-loc. Anyway, it wasn't the Equi-loc that gave out. It was the axle shearing. Jim

James,
   You guys are right. Why not upgrade to 31 spline axles and differential while I have to buy both anyway. Thanks. As far as the Locker vs tru-trac, I'd hate to spend the money buying it, installing it and then not like it. I'll keep you guys posted on what I get. I think you know it'll be soon. Jim

[JimNolan]

Guys,
   I got the Tru-Trac, 3.50 gear ratio and 31 spline coming from R-Mustangs in San Francisco, Ca. Rick Mori is the owner. I looked him up on the internet and tried to find something bad about him. All I found was rave reviews. And, he was more than competitive on price. Now I have to find someone to make axles for me. The mustang axle is different in axle length than the 57. Both have 52" housings but they use a shorter axle than the one I have. Jim

[Zapato]

Jim, check out Dutchman Motorsports they have an incredible reputation here in PNW. asearch for dutchman axles should lead you there.

Zap-

[JPotter57]

Moser axles are still a good deal at $325, but you can look around and find them for $295.  Never had any problems.   Never heard any bad about the Dutchmans either, though.  Stay away from the Superiors you see advertised on ebay a lot.  Do a search on the HAMB or just google them if you want to see why.  Not a well made product, not a lot less than Mosers.
I did buy a set of Strange 35 spline axles for this car, but when I saw the price of a matching locker, I figured a 31 spline would do just as well....the Strange axles run around $450, fyi...

[Hoosier Hurricane]

Jim:

You say the EquaLok is OK, but if the car sat still while you looked underneath to see the driveshaft turning, it wasn't working.  The car should still pull even with a broken axle.  Clutches are probably shot.

John

[JimNolan]

John,
   You're probably right. I thought the thing ought to have pulled itself back home on one axle but it wouldn't. Someone told me once to check the clutches by how much effort it took to break the wheel loose by hand with one side of the car jacked up. The last time I checked it still took effort to break it loose. I bought an extra set of clutches years ago and never put them in.
   I don't know for sure but when the axle broke I was probably doing better than 4000 rpm. God knows what it reved to just afterwards. Would that take the clutches out. The gears look good and it turns on the bench.
   The way the rear differential works always mistified me anyway. On a open differential the tire with the least resistance is the one that spins. Does the clutch pack on a LSD actually have enough pressure on it to enable the tire with most resistance to lay the same rubber streak on the highway as the wheel that's doing the pulling. And if it does, how the hell are you able to break it loose with one side of the car jacked up sitting still.
    I'm sure I'm not the only one that doesn't know how a LSD actually works. Can you put it into layman's terms so I can understand how a LSD that you can break the raised wheel loose by hand can apply as much traction as the wheel that got the most resistance. Jim
     

[JimNolan]

Guys,
  Moser down here in Portland can make the axles, provide the bearings and put the lugs in the axle flange for $445.00. The guy that is building my pig had choosen the Yukon axles that you take to a machine shop and cut to length for $300.00. He said cars like mine with unusual axle lengths chose that axle because it was so strong. Which would you guys go with. Jim
EDIT:  He already ordered the Yukon axles, that's OK. Too late. Anyway, that's $300.00 counting shipping so the price is right. I've got the advantage of having access to a machine shop and good machinest so we ought to be able to cut the length without hurting the intergrity of the metal.