Question About Voiding Warranty

jbannick18 · October 13, 2008

I'm looking to get my gear ratio changed from 3.23 to a higher ratio either the 3.42 or 3.73's in the rear end. I called my local gmc dealer and they said I would have to go to a seperate shop to do this and it would void my warranty. Is there any way I can do this without voiding it?

Also a custom tune would only void warranty if it can be proven to be the cause of the problem? What I have been reading.

Thanks for the help

dlstewart01 · October 13, 2008

If you get aftermarket gears, I would say the warranty would only be voided on the gears.

Don

Neutron · October 13, 2008

Your dealer's service dept is denying doing this with GM gears? This doesn't make sense...

95Sierra2500 · October 13, 2008

Your dealer's service dept is denying doing this with GM gears? This doesn't make sense...

Agreed. If your service department is denying this using standard GM parts, you need to hit up another dealer.

The ONLY way I could see them denying this is if you have a 4x4 but ONLY want to change the rear gears. If that's the case, ANY shop will tell you they won't do it because you need to change the front gears as well. Otherwise you can kiss your transfer case (and possibly your trans to some extent) goodbye.

Ranger · October 13, 2008

Actually you CAN have different gears in a 4x4, you just have to not put in 4x4...On a Bronco forum I frequented a while ago someone said they had 3.55s in front and 4.56 in the rear, and the only time it had trouble was when he put it in 4-LO and it cracked something in the t-case, was stuck pretty good.

jbannick18 · October 13, 2008

Thanks for the responses. I'm going to go ahead and call the dealership again and see if the person I talked to before misunderstood what I wanted.

Silverado4x4 · October 13, 2008

Actually you CAN have different gears in a 4x4, you just have to not put in 4x4...On a Bronco forum I frequented a while ago someone said they had 3.55s in front and 4.56 in the rear, and the only time it had trouble was when he put it in 4-LO and it cracked something in the t-case, was stuck pretty good.

This is NO way you can have differant ratios between the front and rear, the 3.55s in the front will be dragging the rear all around with the 4.11s in 4wheeldrive and it WILL break the driveline. Yeah you will be ok just in 2 wheeldrive but whats the since of having a 4x4 and cant use it. The guy said the only time he broke something was in 4-LO thats bull 4-HI will do the same as it just changes the ratio in the tranfer case.

jrrod2004 · October 13, 2008

now you know why i dont opt for 4WD. It should not void the warranty IF a GM dealer does it with GM parts. If it is aftermarket, GM could potentially void the warranty for the entire driveline....not likely but plausable.

pm26 · October 14, 2008

About the custom tune: I was told by a GM tech that delaers will look for any signs of modifications and supposedly now GM has a way to retrieve the info from the vehicle ECU. Installing a custom tune will definitely void your warranty if something fails in your power train.

Ranger · October 14, 2008

Actually you CAN have different gears in a 4x4, you just have to not put in 4x4...On a Bronco forum I frequented a while ago someone said they had 3.55s in front and 4.56 in the rear, and the only time it had trouble was when he put it in 4-LO and it cracked something in the t-case, was stuck pretty good.

This is NO way you can have differant ratios between the front and rear, the 3.55s in the front will be dragging the rear all around with the 4.11s in 4wheeldrive and it WILL break the driveline. Yeah you will be ok just in 2 wheeldrive but whats the since of having a 4x4 and cant use it. The guy said the only time he broke something was in 4-LO thats bull 4-HI will do the same as it just changes the ratio in the tranfer case.

It was 4.56, and I don't think he ever used it in 4-HI...I don't know the whole story (nor do I remember most of it, it was like 2 years ago) but from what I could remember, he swapped a rear end and the new rear end has 4.56 gears...I don't know why or how he got into that stuck predicament but I know he ended up needing a new T-case and transmission (different breakage on trans, Ford junk) and he ended up replacing the front axle as well. I guess the only reason you'd use it was in a pinch, like the rear end fails or lack of funds...What I would've done was remove the front driveshaft until I had the right gears, but then again I would've waited til I could've swapped both.

jrrod2004 · October 14, 2008

About the custom tune: I was told by a GM tech that delaers will look for any signs of modifications and supposedly now GM has a way to retrieve the info from the vehicle ECU. Installing a custom tune will definitely void your warranty if something fails in your power train.

yup that is correct...

slomo007 · October 14, 2008

About the custom tune: I was told by a GM tech that delaers will look for any signs of modifications and supposedly now GM has a way to retrieve the info from the vehicle ECU. Installing a custom tune will definitely void your warranty if something fails in your power train.

yup that is correct...

While it is correct they have the capability to void warranties due to tunes, has anyone actually heard of it happening on non-diesel trucks? The capability to do it and the willingness to do it (and risk a public relations nightmare) are two different things. I have debated about getting a spare ECM and TCM before getting my truck tuned but to be honest the odds of me getting warranty work voided on my truck due to the tune are slim to none from everything I've read.

gvbhunt · October 14, 2008

I always figured that if I had to take it in for warranty work and they said that there was something "fishy" with the ECM and TCM then I would be honest about what I did. Personally I would be pretty pissed if they voided my warranty because I went in and cleaned up the fuel trims, increased the clamping pressure on the trans bands so as not to burn them during "sloppy" stock shifts, and made AFM actually work.

Now if I went in and radically changed things I would not expect them to cover anything.

iscsidude · October 14, 2008

About the custom tune: I was told by a GM tech that delaers will look for any signs of modifications and supposedly now GM has a way to retrieve the info from the vehicle ECU. Installing a custom tune will definitely void your warranty if something fails in your power train.

yup that is correct...

Okay. I'm confused.

Is the ECU different than the ECM ???

In other words, if I keep my ECM stock and only put it in for dealer visits, is there something called an ECU that will tattle so to speak ???

2000DV4.8 · October 14, 2008

About the custom tune: I was told by a GM tech that delaers will look for any signs of modifications and supposedly now GM has a way to retrieve the info from the vehicle ECU. Installing a custom tune will definitely void your warranty if something fails in your power train.

yup that is correct...

Okay. I'm confused.

Is the ECU different than the ECM ???

In other words, if I keep my ECM stock and only put it in for dealer visits, is there something called an ECU that will tattle so to speak ???

No, ECU and ECM are pretty much synonymous and interchangeable terms as far as I know (engine control unit/module).