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Discussion Starter · #1 ·
I need the rear end ratios for a 91-93 Chevy wagon. Please list all the options and if they were installed with limited slip or not.

Also is the entire rear axle compatible with my 2.93 car ABS system. I can reprogram the Speedo and shift points, but am worried about the ABS.

Here is why....

I have my rear end with the axles out trying to find a shake and I'm not sure what the problem is. I know where I can get a complete rear end from a 93? Caprice wagon, or I can get just the axles.

I removed my axles and have mounted on the centers in a metal lathe. The hub runs within 0.001 of the center. The shoulder where the axle bearing rides is 0.008 runout on the axle that I thought was ok and is 0.018 on the axle I thought might be bent. The centers of the axles are WAY off due to the casting and machining process. One is 0.062 off and the other is 0.055. The splines are both off about 0.008 runout.

So what is the deal? Do I have one bent axles or are both? Or are they both just bad factory axles that slipped by QC or is GM just pretty lax on these things?

I cannot move the carrier or pinion, so they are fine. The driveshaft has not lost any weights and the joints are fine. The tranny output does have a little play in it.

The shake is a slow shake that is road speed and the worst from 65-75 MPH. It is not a fast shake like a driveshaft.

I jacked the car up and it shakes with the wheels on, wheels off and drums off. So with the axles being the only thing left I suspected them.

So now I have decisions to make. Thanks for the time!
 
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Discussion Starter · #3 ·
I found the same thing with my Camaro axles. Way out of spec in my book. Had em on the lathe and the cone section from the bearing surface to the wheel flange was crazy bad. All the machining didn't really smooth things out though. The vibration was my driveshaft.
 
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Discussion Starter · #4 ·
Rex, for the most part the 91-93 wagons had 2:73 rear gears, 2:53's were also common. 2:93 was the tow package, and police ratio. 3:23 was the 9C1.
Limited slip was an option regardless of gearing as I understand it.

You can not reprogram the speedo via the computer. This is done by changing out the drive and driven gears at the tranny output shaft and VSS. I recommend changing the VSS sensor as well.

You must also change the reluctor to match gears.
Performance Automotive Transmission Center is the source for speed gears.

Been there, Done that. Good luck!!
 
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Discussion Starter · #5 ·
PS, a while back I compiled a compendium of all the early series model years axle ratios for Bill Harper. Im not sure what he did with it, but I have all that info.

I am currently in the middle of a job for GM, and can get you more info on friday.
 
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Discussion Starter · #6 ·
I'm not sure, but it seems like you might have missed that this is going into a 95 Wagon.

AFAIK the speedo can be changed in the programming and the ABS reluctor will already be on the factory 3.23 gears in the rear end, which I am swapping as a unit. Did I miss anything?

BTW this car did have a 3.23 posi unit, so lucky me I guess! So far so good. I'll have the unit out in the morning. The car had 88K on it.

I'll let you know how it goes!

Thanks!
 
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Discussion Starter · #7 ·
Here's a chart from the FSM:

Rear axle usage chart (from 95 FSM)
Ring Gear Axle Codes Ratio Brake Posi?
7-5/8" 2GF/2GG 2.93 9.5" drum No
8-1/2" 4ZB/2YF 2.93 11.0" drum No
2LQ/2YG/2NS 2.93 11.0" drum Yes
2LU 3.23 9.5" drum Yes
2LT 3.23 11.0" drum No
2LS/2GU 3.23 11.0" drum Yes
2LY 3.23 Disc No
2LZ 3.23 Disc Yes
2LW 3.08 Disc No
2LX/2LL 3.08 Disc Yes
2YN/2GC 2.56 11.0" drum No
2GQ 2.56 11.0" drum Yes
4ZB and 2GU were Taxi
2LY, 2LZ, 2LW, and 2LX were Police
2LL was Impala SS
2YN, 2YF and 2YG were the wagons
2GC, 2GQ and 2NS were the Roadmaster
Axle widths:
1598.0 mm 2GF 2CG 2LQ 2LU 2LL
1566.0 mm 4ZB 2LT 2LS 2GU 2LY 2LZ 2LW 2LX 2GC 2GQ 2NS
1642.5 mm 2YN 2YF 2YG (Hopefully email won't scramble my spacing...)
teeth: Ring gear:pinion
42:13 2LU 2LT 2LS 2GU 2LY 2LZ
41:16 2YN 2GC 2GQ
41:15 2GF 2GG 4ZB
41:14 2LQ 2YF 2YG 2NS
40:13 2LW 2LX 2LL
 
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Discussion Starter · #8 ·
Having re-read your above posts, you never said you were putting this into a 95 wagon.

You specifically asked about 91-93.

Yes the reluctor from the factory will match the gear.

Did I miss anything??
 
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Discussion Starter · #9 ·
Sorry. I didn't directly say it was going into a 95. The 95 in the signature is my only wagon.

So far this is what I have come up with.

Must change the ABS sensor to use 95 wire routing. The 95 sensor wire is about 15 inches longer. When doing this you have to remove a plastic ring and o-ring from the 93 axle and swap with the 95 o-ring to make the 95 sensor fit the 93 axle. If you don not do this then the 95 sensor will not properly fit the 93 axle. It won't go all the way in.

You could probably use the 93 sensor and route the wire a different way.

95 LCA have a holder for the emergency brake cable on the drivers side, 93 did not. Not an issue.

93 UCA have a different wire holder for the ABS sensor, not really an issue.

95 uses a slightly different location for the brake hose, but the hoses are the same.

I think that is all for differences.

The 93 axle shafts don't have near as much runout as my 95's. Hopefully this will solve some problems and I'll end up with a 3.23 posi instead of a 2.93.

I should have the axle in tonight. The 93 and 95 axles are both on the shop floor.

I think this should be included in the Cheap Ass Mods list. $200 for the entire axle that includes a gear swap. 2.56ers should be all over these things!
 
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