ok here it is... today i went up to the local drag strip to run the truck for a few runs and i love how the truck is running in the overall picture.. but i need more traction... i have some ET Drags mounted to second pair of rims that i used today but they still didnt help out... i did 11 runs today and 7 of them i broke traction out of the whole spinning the slicks all the way into 2nd gear while the other 4 i just spin a little and then catch shortly after launching or i wouldnt lauch as hard.......but here is the problem im only spinning the back right tire......im assuming my traction problem is the lack of posi rear end or worn out posi rear..... do these trucks come stock with posi and its just worn or... how much you think it be for a posi rear if i need to convert it over.....
here are the runs....

Reaction: .212, .456, .318, .089
1/8th: 8.61, 8.89, 8.82, 8.45
1/4: 12.93, 13.11, 13.02, 12.85

 

You might wanna look at more of a locker than a posi. A locker would work better. Either way, I have a feeling that your truck either didn't come with one from the factory (I don't know why they didn't put them in all but whatever) or yous is just slap worn out. Do a search on here for posi's and lockers and you should find some info on pricing and what works best.

 

what are your 60' times?

are you doing a proper burnout? don't run through the waterbox w/treaded tires... w/ drag radials, drive around the box, back up to the edge, and start your burnout.

you should be fine w/ a tight posi

 

With all that torque go to a Detroit locker and never look back. More expensive?.....yes, Break them?.............NO!

Rick

 

you may have a LS that's worn out, look at the tag under you hood to see if you do have a LS. I swapped in an axle from a 98 that had a powerlok in it and I can put one tire on ice and the other on pavement and they stay locked together. So I would say a powrlok is the way to go if you're riding on the street. of course a selectable would be the best of both worlds but big $$.

 

today ill check under the hood at the engine tag...... im not sure if it has posi.. or limited slip.. but all i know is even with the ET Drag Slicks i had yesterday the right tire would burn rubber while the left did nothing on the tire cleaning before the prestage....i was just looking over some of the video footage we took and all the launchs the truck spun the right rear tire for some sort of time frame while the left just ran along.......

 

ok today i checked under the hood and i couldnt find anything on the rear axle... also there is no tag on the rear diff cover....when i bought the truck had an aftermarket cover so im guessing they tossed it. Anyone know what the rear is in my truck?.... i was looking at lockers but i dont know which one to look at because i dont know much about rear ends... haha never touched them or messed with them... one thing i like to do is change the gearing a tad.. because im already red lining in 4th coming across the 1/4 mile mark as it is now....

 

If it's a factory automatic, you should have a D70 under there. There are a fair amount of options out there. Personally, I would call a drivetrain shop/expert and give them the 411 on your setup and intended use. Those folks live and breathe diffs and ring gears and such--take advantage of their experience. I have a Detroit Locker. I feel tough when just saying it It's a no-compromise traction aid that definitely has it's quirks on the street, but I've learned to drive around it.

 

I would highly recommend NOT using a detroit if you ever tow anything with any weight. Or any locker for that matter. Limited slips are best for towing, as the quirks of lockers are exaggerated a lot when towing from the extra on the rear axle.

To find out what you have, jack the rear axle up off the ground completely. Then spin one tire by hand, and if the other spins the opposite way, it is open, if it spins the same way, it is a limited slip.

The other way to find out what you have, and it is best, is to open the diff up and look. but it is also more expensive.

 

I almost second your motion

I dont know if your truck came with a dana 80 or similar rear end like mine did, but if you have an LSD im thinking that it has gone kaput...


TRCM also makes a good point, lockers are noisy and really jumpy on vehicles, BUT if your truck dont tow much and isnt your dd, then go for it, if not the more expensive alternative is an ARB or detroit electrac

Rick

 

I daily drive the truck but i have yet t otow anything but my motorcycle trailer which isnt anything to worry about...

 

I run an Eaton limited slip in a mud truck with 38.5 inch tires, 4.88 gears, and around 400 horsepower. This differential has withstood 2 years of hard driving, burnouts on pavement, and hard off road use. And yes detroits break. I have personally seen at least 5 of them break.

 

I've seen several detroits break also. I am running one of the lunch box lockers (lockrite) in my 79 RC, and I have been abusing it with more hp, and bigger tires than they recommend, and it has held up for over 10 yrs, and it even survived when I cracked both axle tubes open.

 

you may have the limited slip with the clutch pack set metel,metal,metal, then friction,friction,friction. the limited slip in my 97 is tight as can be with 268k on it. but the later year trucks they stacked the clutch pack to slip alot easier. i am not sure what year this was. but i have heard of much better results stacking they the way they were designed. but first jack it up and see if you have a posi or open diff.

 

gah i looked in the phone book for a local driveshaft or driveline place.. and i found nothing sucks living in a rural area sometimes...