irocnroll89

iTrader: (4)

i have done alot of research and have found the $150 rearend i got from the W/Y has a "locker" installed in it. With that, the rear was a 1985 iroc 5.0 h/o, 7r4, with 3.42 ratio and discs. The rear would "bang" into engage when i cranked the yoke by hand hard. Now i have the whole thing apart and have found the (posi) has NO cluthes. It does have 2 weights that are spring loaded. Any how there are no real markings on the unit other than a 4 digit number. I have yet to pull the ring gear off, going to though since the stock gears blew up. I have a new set of richmonds for it. I want to know if it is a stock unit or maybe a DETROIT? I am seriously leaning toward keeping the posi, what do you think? THE SHAGGY IROC

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'89 SHAGGY IROC
L98 7r4, all free stuff,T.E.S.,HOOKER CAT BACK,KYB,ACCEL8.8,JET fan sw. etc.
so much to do , so little money

TomP

'84 models (and maybe '85?) used an Eaton gov-lock. A governor was hung between the spider gears, and would expand outward if slip was detected. Supposedly Auburn couldn't supply GM with the posi's, so GM went to Eaton. The Auburn unit is said to be superior, though. In fact the '84 3.73/posi/disc axle I swapped in had some chunks missing from the spider gears (from the harsh clunking). "One of these days" I'll have to change that


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OLDYELLR

The Eaton Locker *DOES* have clutches. I know, because there were pieces of clutch plates as well as bits of spider gears that fell out when I removed mine! It let go at the drags and I don't know whether something had been broken long before and this is how it finally died, but the case was cracked wide open and the spider gears and the bevel gear on one side were chewed up and various other bits broken. When the axle is jacked up you can't tell it's a limited slip unlss you spin one wheel by hand. At about 100 rpm difference the diff will lock up. When the clutches are worn, this lockup becomes abrupt and can cause a quick transition to oversteer if the inside wheel tries to break loose under power in a turn.

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1985 Yellow IROC-Z 5.0 HO, T-5 3.73 Torsen, 4 wheel disks
PFCM pads, GTA wheels, Koni yellows, B&M Ripper, Dynomax

GMTech

It definatly sounds like an Eaton locker, the same ones used currenlty in the GM trucks. And yes, they do have clutches.

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'87 Trans Am
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22# injectors,
Whatever chip I feel like burning,
JET AFPR, Ported Plenum,
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-->14.97 @ 94.9 MPH<--

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irocnroll89

iTrader: (4)

how can i service an EATON locker? THE cluthces and such. How do i kow the clutches are worn? When the yoke is spun hard the axles both lock up abruptly. Is this normal or a sign of clutch wear? THNX this is helping my decision to keep this locker or get a auburn (though funds are low) THE SHAGGY IROC

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'89 SHAGGY IROC
L98 7r4, all free stuff,T.E.S.,HOOKER CAT BACK,KYB,ACCEL8.8,JET fan sw. etc.
so much to do , so little money

OLDYELLR

Don't know if spinning the yoke is a valid test. I know that these Eatons "look" like an open diff when you turn one wheel when on jack stands. You really can't tell if the clutches are working correctly without load. My 1985 Helm manual has about 4 pages on how to service and repair the Eaton.

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1985 Yellow IROC-Z 5.0 HO, T-5 3.73 Torsen, 4 wheel disks
PFCM pads, GTA wheels, Koni yellows, B&M Ripper, Dynomax

Biochem

Did these Eaton Lockers come in 9-bolts too? I had mine (9-bolt) apart when I got it and the differential doesn't look anything like a 10-bolt posi. It almost looks more like the 10-bolt open diffy, but both wheels do spin

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

GMTech

The Eaton Locker can be serviced. There is a governer inside there w/ weights. When one wheel spins 100 RPMs faster than the other, the clutches apply and the axles lock up.

------------------
If you live in Southeastern US, check us out!
South East Thirdgen

GM Master Tech
ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
Whatever chip I feel like burning,
JET AFPR, Ported Plenum,
TB Coolant Bypass, Custom Cold Air,
SSM SFC, KYB Shocks, Boxed LCAs, Wonder Bar,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
-->14.97 @ 94.9 MPH<--

'97 Bonneville SSE