Offroad Trailblazers and Envoys

running 35's on a 3.42 (g80)

G80, GU6, GT4, GT5, WTF? This section is for gearing and driveline stuff.

by MartinTheLaker » Wed Apr 30, 2014 12:24 pm

Hello, just wondering if there might be any problems I may encounter when running 35s on my 3.42 gearing.
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by HARDTRAILZ » Wed Apr 30, 2014 12:30 pm

Transmission heat and failure

Gas mileage

Lack of power

Far less towing ability

I am quite certain the I6 can turn the tires and be fine for putting around town. Stock 200HP heeps do it with similar gearing on 35s and bigger all around me. Depends on your mission and willingness to trade off things to run them. 3.73 and 35s did not feel all that bad just cruising around, but the 4.10s are much nicer.
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by mikekey » Wed Apr 30, 2014 12:47 pm

NO

Unless you're cool with saying goodbye to 4th gear, because your transmission will never lock up. See all the above why it's a dumb idea. It's hard enough to keep the transmission in lock up with 3.75's around town it's not bad, unless I'm cruising then I notice it. Don't dare try to do it without a transmission cooler.
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by MartinTheLaker » Wed Apr 30, 2014 12:59 pm

Ok thanks very much. would I be safe with a 33" tire? Or is that still too big?
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by Cable810 » Wed Apr 30, 2014 1:07 pm

That should be fine long as you add a tranny cooler. Bacon is running 33s, 3.42s and a cooler don't think he has had any issues. Generally the safest bet with 3.42s and no cooler would be 32s
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by mikekey » Wed Apr 30, 2014 1:12 pm

Trail X has been running 32's with 3.42's and a cooler for a long time. Bacon now has 4.10's although I think he ran into problems, did he ever gfix/finish his regearing.

33's should be ok on 3.42's with a cooler.

Cooler should just be the default you should do it recommendation for anyone going over 31 inch tires, IMO. Seriously, they're like under $70 and don't' take but a half hour to install one.
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by TBYODA » Wed Apr 30, 2014 2:42 pm

:Iagree: :Iagree:

Martin a word of advice before you jump in, do more reading on this site before you make any decisions. Read the intro thread here before you make some costly mistakes, a lot of your answers are in there. viewtopic.php?f=8&t=3060 Figure out your "mission" what you want to do with your TB.

I am fairly new to being lifted however I have been reading non-stop since I joined last March in 2013 to fully understand what I was getting in to and the risks, I am still am reading daily. In many area's I am still behind the eight ball in understand but I'm researching so I can understand. The guys on this site are a great bunch and we will help you but there is ton of info here already to answers all your questions, read every stickily, read over the build threads. Read, read, read. I understand you want to lift your TB NOW but the do research in the end you will be better for it and save $$.

BTW IIRC DirtyBacon ran 33" for a year without a cooler and burnt up his transmission. Not good ~$1500-2k rebuild vs ~ $70 and 1/2-1 hour of your time. :wallbash:

cooler examples
viewtopic.php?f=76&t=2305#p68928
viewtopic.php?f=74&t=4612#p102755


Good luck :cheers:

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by Shdwdrgn » Mon May 05, 2014 11:09 pm

Don't forget to check out the gear ratio calculator. It gives a great visual between gear ratios, tire size, and what affects each has on your economy/power. Admittedly it is a royal pain to change out your gears, but its totally worth the effort to match gears to your tire size for all-around driveability.
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by darring70 » Wed May 07, 2014 9:01 am

Cable810 wrote:That should be fine long as you add a tranny cooler. Bacon is running 33s, 3.42s and a cooler don't think he has had any issues. Generally the safest bet with 3.42s and no cooler would be 32s

The tranny cooler should be installed on the inline or the outline of the stock tranny cooler?
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by navigator » Wed May 07, 2014 9:05 am

If I remember right most install it on the inline though there have been a few discussions/disagreements about it.

I think James (Trail X) has a good write up in his build thread if I remember correctly.
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by mikekey » Wed May 07, 2014 9:38 am

He does have a good write up, a few of us do. The debate is mostly around your climate and cooling it too much.

I live in florida, so mine is cooled after the radiator (inline), some folks cool it before the radiator (outline). This allows the radiator to warm it up to operating temperatures. If you live in Alaska or Minnesota or something, this is probably a good option. Guys like me in Florida or in Arizona or Texas are more than likely going to be best off with it being after the radiator.

I'd also argue if you're going to be towing a lot with it, you're going to want it (inline) as well.

A few guys like Moots have also installed thermostats, because he live in New York.
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