HELP! 4.56 gears not compatible???

[radarb8]

Today I dropped my car off at the local performance shop to get my 4.56 gears installed. About 3hrs after I dropped it off I got a call saying they could not do the work because my housing is not compatible with 4.56 gears (2005 auto).

The shop said when they pulled the cover there was an orange tag inside stating 4.56 gears may not be compatiable with this housing, check VIN # with dealer for compatibility. He called the local chevy dealer and they told him that my housing (based on my VIN#) was listed as not compatible with 4.56 gears.

Can someone help me out here? I have read everything here on 4.56 and have never heard this mentioned.

Best, Ray

[hdflstf]

Don't have a good answer. My thoughts are if the gears are American Axle, they should fit. If they are aftermarket, they may not. What year/vin SSR?

[radarb8]

Yes the gears I want to install are American Axle. I have a 2005 auto VIN#1GCES14H45B114536

[Doug Allen]

If they are American Axle gears and made for the automatic, they'll fit.

[radarb8]

Any ideas as to what the orange tag inside is all about? Why are they saying it won't fit based on my VIN?

[radarb8]

I'm really afraid of dropping close to a gnote on this only to destroy my rearend. The thing that gets me is the very specific message about checking the VIN with the dealer and after doing so I'm told it's not compatible.

[Doug Allen]

I suspect the warning is because 4.56's were not designed for ANY SSR. I don't know what the tag is.....

I'd call (John) at J & S Gear and tell them your story - they know a lot about these cars and gears.

[radarb8]

Talked to John @ J&S gear just now and he has never seen this tag inside the housing?? Now I'm scared.

[hdflstf]

Early 05. The only other thing I can think of is that GM can't set the computer. Your SSR has the same rear as the others.

[bronco]

If you have a 10 bolt 8 inch Diff. the only thing you can use is 4:10 or 4:11.

I have an ' 04 and that is my problem. Your '05 may be one the first ones off the line without the 8.5 or 9.5 inch diff. Just a thought.

bronco

[chopper]

My 04 was made in August of 04. I would think that it was one of the last o4's made. I had 4:56 gears put in and was fine.

[AusTexKid]

Originally Posted by chopper

My 04 was made in August of 04. I would think that it was one of the last o4's made. I had 4:56 gears put in and was fine.

And my 05 is 16549, about 2000 units after radarb8's. No problems with the 4.56 gear install and no tag inside. And I even used an aftermarket gear set (Richmond). I think I would find another shop to do my install. The whole tag story sounds fishy to me. Did they actually show you the tag?

[Paul Simpson]

Originally Posted by AusTexKid

And my 05 is 16549, about 2000 units after radarb8's. No problems with the 4.56 gear install and no tag inside. And I even used an aftermarket gear set (Richmond). I think I would find another shop to do my install. The whole tag story sounds fishy to me. Did they actually show you the tag?

I agree with the Kid, the whole thing sounds like smoke. Read the tag for yourself and/or find another shop, preferably one that builds or works on race cars. Good luck.......Paul

[waysouth6speed]

Originally Posted by hdflstf

Early 05. The only other thing I can think of is that GM can't set the computer. Your SSR has the same rear as the others.

I'm betting that our rocket scientest is right. I'm thinking the "tag" was on the techII computer (flag), not an actual "tag" on the rear end. Like Doug said " the warning is because 4.56's were not designed for ANY SSR".

[Neal2004]

I have an 04 and have had the 4.56 gears in for a long time and never had a problem. Of course I had to have a westers tune which worked out great