Guys who went to 35's . . .

[JWSchmidt3]

Are you having any issues with, or does it seem your transmission shifts at much different intervals than from stock?? I had an Adv. H3, and I am currently driving a 2007 dealer loaner while my lifted H3 is at the dealer, and my suspician is confirmed. One of the issues I sent the H3 in for is the tranny shifting. It always wants to shift down to low gear way too early. Is this because of the 35's?? Is there any way to properly calibrate the bigger tires?? My truck drives like a turd compared to thos '07. BTW, I also have a CAI and exhaust installed. Any help appreciated, as the dealership has yet to give me any real hope.

[HummBebe]

I think your only option at this time is to pay for it to be professionaly tuned.

GM has no computer re-program as of yet.

[meyergsr]

Your going to have to get your engine computer recalibrated for the taller tires the dealer wont do it. Go to the aftermarket like PCM for less. http://www.geocities.com/pcmforless/index.html

[JWSchmidt3]

Here's another issue, I bought the truck new from the dealer with this package installed (they call it the Xtreme Comp Pro package). The sales guy specifically said, "Oh yea, it's all been re-tuned for the bigger tires, intake and exhaust. They use the Tech-II". My extensive modding with Corvettes told me he was probably full of it, but I'm now holding them to it. I'm just curious if anyone else had such a drastic impact when they changed to 35's, or if I have another issue.

[CrisB]

You bought that H3 like that? The dealership probably did that themselves, somebody there thinks he knows what he's doing. I would definitely hold them to it, they built it.

[HummBebe]

Originally Posted by JWSchmidt3

Here's another issue, I bought the truck new from the dealer with this package installed (they call it the Xtreme Comp Pro package). The sales guy specifically said, "Oh yea, it's all been re-tuned for the bigger tires, intake and exhaust. They use the Tech-II". My extensive modding with Corvettes told me he was probably full of it, but I'm now holding them to it. I'm just curious if anyone else had such a drastic impact when they changed to 35's, or if I have another issue.

That is an outright lie. There is no Tech II program for tire increase to 35". Only from 32" to 33".

[JWSchmidt3]

Originally Posted by Cris Burkhalter

You bought that H3 like that? The dealership probably did that themselves, somebody there thinks he knows what he's doing. I would definitely hold them to it, they built it.

Yes, but they contracted an offroad shop to do the package. The dealership is pretty reputable. I'll hold them to it, but the fact remains the PCM can not be properly calibrated for the bigger tires, and I'm wondering what other guys who have gone to 35's have done.

[JWSchmidt3]

Originally Posted by HummBebe

That is an outright lie. There is no Tech II program for tire increase to 35". Only from 32" to 33".

That's what I thought when I bought it, but was only 99% sure. I won't call someone out unless I'm 100%. Tomorrow I pick up the truck, and meet with the Hummer GM.

[HummBebe]

Originally Posted by JWSchmidt3

I'm wondering what other guys who have gone to 35's have done.

Wheel the hell out of it

[K9sH3]

JW,
I would hold them to it also, they lied (fraud) to sell you a H3. If you have that in writing you may have a new 3 coming if this one turns out to be a POS. In the mean time, I would do as Hummbebe said "Wheel the hell out of it" they (dealer) customized and gave it that name.

No amount of so called tuning combined with aftermarket intake and exhaust systems will counteract the hit to acceleration caused by the larger diameter 35" tires. Your gearing is now substantially taller than the stock H3 w/32's or 33's.

[JWSchmidt3]

Originally Posted by Steve - SanJose

No amount of so called tuning combined with aftermarket intake and exhaust systems will counteract the hit to acceleration caused by the larger diameter 35" tires. Your gearing is now substantially taller than the stock H3 w/32's or 33's.

So, would a gear change help??

Originally Posted by JWSchmidt3

So, would a gear change help??

Gearing change would certainly help. But others on this forum have researched that and can talk feasability.

[HummBebe]

Originally Posted by Steve - SanJose

No amount of so called tuning combined with aftermarket intake and exhaust systems will counteract the hit to acceleration caused by the larger diameter 35" tires. Your gearing is now substantially taller than the stock H3 w/32's or 33's.

Using a calculator would show that it reduces you to about 4:29's. Still better ratio than on an H2

[BACKNBLACK]

The Hummer H3 has "Adaptive" shift learning. Even going from 32" to 33" no computer "reprogram" is necessary. I have 35" BFG MT and mine shifted funny for about 3 days and then bang "Adapted" Talk to your H3 Mechanic he should be able to verify this. Hummer engineering has also commented on this in a few earlier articles during the "promotional phase of the H3" Hope this helps.

BTW here are the stats for the 35" Change from the 33'S"

[BACKNBLACK]

BTW even with a 2 1/2 Turn of the TBAR I still rub against the plastic and A arm at full crank. Nothing to get nerveous about but just be aware that if you like a "RUB FREE" Hummer than 35'S" are not for you :-)

[JWSchmidt3]

Originally Posted by BACKNBLACK

BTW even with a 2 1/2 Turn of the TBAR I still rub against the plastic and A arm at full crank. Nothing to get nerveous about but just be aware that if you like a "RUB FREE" Hummer than 35'S" are not for you :-)

I already have 35's, along with a 4" lift. My issue is with the transmission and how it shifts. See my sig and original post.

[BACKNBLACK]

Originally Posted by JWSchmidt3

I already have 35's, along with a 4" lift. My issue is with the transmission and how it shifts. See my sig and original post.

OOPS :-)

In that case....... is it possible the lift has caused your issue. In my Hummerclub that I manage none of my members that went to 35's have this issue longer than a few days??? The only difference is the lift???

[jdrew]

Originally Posted by HummBebe

Wheel the hell out of it

+10 points for an excellent post!

[lotus4s]

Originally Posted by JWSchmidt3

I already have 35's, along with a 4" lift. My issue is with the transmission and how it shifts. See my sig and original post.

As someone else suggested, contact PCM for less. They can adjust the shift tables....