ls14jay

iTrader: (6)

Last night at the strip the car was hooking very well. On my last run of the night after running several 1.6 and one 1.5 60' I launched a bit harder and lost power to the rear wheels. No noise like something broke or anything. I just dimped the clutch(new) and it jumped forward a hair and that was it. Today I jacked up the rear of the car and went through the gears and the wheels moved in all gears. I was puzzled, so I dropped the car down and tried again but with the weight on the rear tires it doesn't move an inch forward or reverse. I put a video camera under to film the driveshaft to make sure it was spinning and it was. With the tires in the air I was able to spin the wheels while in neutral with no wierd noises. Both tires went the same direction. While in the air I was able to spin the wheels with force when in gear.The rearend has about 15 good launches and some street driving. I bought it used/new from a member and it worked fine till last night. The specs are

Moser 12 bolt
-Motive 4.11 gears (brand new, prefessionally installed)
-New bearings and other timken goodies/seals
-New spicer bolts on the yoke (1350 Yoke)
-Welded LCA relo brackets
-Aluminum Performance Girdle (a nice upgrade, it reads MOSER in polished aluminum, the rest is black)
-Upgraded 1/2" ARP studs (great for serious racing applications)
-Eaton Posi
-33 spline Moser axles

So my question is should I go ahead and pull the cover, and if so what am I looking for??
Not sure whats involved in fixing this. If a gear change is needed should I stay 4.11's.

I'm running 11.5-6 @ 119 ish on motor nearing the redline in 4th at the end of the quarter on 26"tires. I may some day spray a small shot if my friend passes me on motor but I guess I could go to a 28" tire and keep 4.11's
The car is 75% strip and 25% street but becoming less street all the time.

thanks for the help
Jay

XtraCajunSS

iTrader: (2)

What clutch are you running? You may have an issue there. It might engage enough to spin the wheels but not enough to move the car. Can you put it on level ground apply the e-brake and check (w/mirror or camera) to see if the driveshaft is still turning when you put it in gear?

Shane

ls14jay

iTrader: (6)

I'm running a almost new Textrailia z-grip. I did put the tires on the ground when I video taped the driveshaft. I put it in first gear a revved up to about 2000 rpm and the driveshaft was spinning, rear pinion was spinning at engine speed.

???

ski23

iTrader: (21)

This is why I went straight to a 9". I was in same boat but, with the shitty 10 bolt and could not make up my mind, 12 bolt or 9". Well after reading posts like these my mind was made up. Goodluck with the fix and I hope its something simple

ls14jay

iTrader: (6)

Thanks
I came accross this 12 bolt with driveshaft and torque arm for a good price locally saved about 1000.00. I didn't think I would blow it out this early. I guess the eaton can be rebuilt reasonably or could switch to a true trac? I could go locker since I drive it once and a while to the corner store or to work just when I feel like driving it.
Will pull the cover off this week some time.

Jay

cam

iTrader: (9)

Likely grenaded the Eaton. Dont do the Truetrac they dont like dumps on sticky tires. Another Eaton is probably your best choice unfortunately or go for a spool if its not street driven

BadBandit69

iTrader: (13)

i would go spool or locker. not true trac.

omcar

iTrader: (10)

+1 on Locker

stealth355tpi

Spool here, you'll get use to it. stories like this make me worry about mine but i never really drop it with a sticky tire.

SuperSlow02

iTrader: (16)

Cant speak for a 12bolt true trac, but my 9" is holding after a good amount, but im with everybody else, go with a locker. When my trutrac dies, ill go locker

ls14jay

iTrader: (6)

Definitely leaning towards a spool at this time but I haven't opened up the rear yet to see what happened. I would say it's 75% track use 25% road. If I put a spool in it will probably go to about 90/10%

Jay

pro382d

iTrader: (1)

it sounds like you may have killed a diff side bearing, which lets the diff slide over and lets the ring gear lose contact with the pinion, usually destroying the ring and pinion.
if by chance you have broken the eaton carrier, check into replacing it with a factory gm posi unit. when it comes to a 12 bolt i dont think they can be beat. I have run one for 6years and litarally thousands of passes and havent had the cover off of it since it was put together. this is with a trans brake in a mid ten second car at 3200 lbs. cutting mid 1.40 sixty foots.

EPP

iTrader: (22)

Jay, let us know what you find out when you open it up. Bob

MusTangKilla01Z28

iTrader: (-1)

it sounds like the clutch to me! Hopefully its something easy tho GL with it jay.

ls14jay

iTrader: (6)

Took the cover off a found these.


Small gears inside the posi unit, spider gears right??
One gear has 2 teeth left on it and the other one has a few missing.

Jay

Justins00ss

iTrader: (18)

Well there you have it. Time for a new posi unit. Iam in the same boat right now. I broke my TruTrac on street tires with no track time on a 10 bolt. Going back to a regular Auburn Pro.

RAMPANT

iTrader: (17)

Get the upgraded after market spider for the eaton. Mine has been fine since I blew mine to hell. Did the diff lock up when this happened, if so the gears are likely hurt too. If not you may be fine. My gears broke the next time out. Replaced them and have been good ever since.

I PM'd you the information on him.

cam

iTrader: (9)

Aftermarket side gears? Sounds like a winner can you PM me the contact info too?

ls14jay

iTrader: (6)

no the diff didn't lock up. I went with the spool as EPP suggested. Sure was surprised it broke so soon, thought it would be stronger.

Live and learn.
Thanks
Jay