Tire size on a 3.42?

[AGENT SMITH]

Hello, I'm a noobie who's trying to put a plan together to lift his TB. Then I came across the gear ratio stuff, and I just want to make sure that what I'm thinking is O.K.

I've got the 3.42 and am only planning on running 265/70R17s or 31.6" tires. I'm assuming that this is a pretty standard upgrade to go from the stock 29.5" to the full-size Chevy truck tire size. Been doing a bit of reading and saw the gear ratio calculator, which puts 31.5" tires with a 3.42 in the pink of the chart. Just clarifying that this is a common and safe upgrade before I go any further. And by the way, I'm planning on turning my TB into an upgraded daily driver capable of handling some light off-roading, nothing crazy. Thanks for any reassurance or help.

[DirtyBacon04]

Yea, that'll be fine. No bigger on 3.42 is advised. A xmsn cooler is recommended, also, but not required.

[Cable810]

[v7guy]

Yup, you'll be good, I drove around with 3.42s and 32s for a couple years, no issues

[Trail X]

The pink section is really there just to urge you to get a transmission cooler.

I drove mine for 5 years with 32s on 3.42 gears with a cooler. It's not the optimal setup, but it will work.

[AGENT SMITH]

Ok, thanks. Sounds like I should be ok without the cooler? Won't be able to right of the start because of limited funds set aside for my initial setup. Might be something good to consider down the road.

[navigator]

a lot will depend on where you live and what you do with your truck.
Fill out your location and it will give us more info.
If you live somewhere hot and tow a lot that might be too much on your tranny without a cooler.
If you tow a lot in hilly terrain it might be too much as well.
I'm running that combo in the flat lands of SE NC without a cooler and if I tow my bass boat in 3rd during the summer the temps stay down pretty well (<215) otherwise they get too warm (225) for my liking. I seem to recall last summer on the interstate running 75mph it could get a little warm as well.
I have a scangauge II so I can monitor my temps and change my driving a little if I notice it getting too warm.

That being said I am about to install 4.10s and a cooler.

[v7guy]

I fully expect I was overheating my transmission with no cooler and 3.42s and 32s. It lasted a couple years with no cooler here in the NE with trips down to VA a couple times a year. I just went with the blind and dumb approach, I didn't know how hot it was and I didn't look. I have no doubt I was on borrowed time without a cooler.

[TBYODA]

With limited "funds" I'd suggest you save the $50 - 70 bucks you'll need. It is pretty easy install and cheaper that a tranny rebuild. I am running 3.42 and 32" and when I was down at the last TECORE I seen my tranny temps get up to about 200 - 210 with the cooler I am running a couple times. Did not stay there long but i am sure glad I put one in, would have been a lot hotter with out one.

[Trail X]

Josh, the big issue is the unlocking of the torque converter clutch. If you can drive around and monitor that the clutch stays engaged, you'll be fine. You start making a ton of heat when the TCC unlocks. This is why down shifting into D3 works to cool things down, because the rpms increase and the engine doesn't need the extra rpm (and thus power) boost that unlocking the TCC gives you. If you can just monitor the TCC, you'll be in good shape.

It just takes a little practice of paying closer attention to the RPMs of the engine. You can somewhat feel it engage and disengage, and you can see the rpms jump 200-300 rpms between locked and unlocked.

I also agree with Robert. Save up the money and do the install as soon as you can. It's also a dangerous proposition lifting and wheeling a truck with limited funds. Make sure you have a safety cushion of cash, in case you blow up your trans or a diff or a CV shaft.

[AGENT SMITH]

Yeah, haven't filled in my profile info yet. I'm from Michigan, so it's relatively flat and I don't do any towing. Like I said earlier, this will still be my daily driver, but hopefully become more capable of handling light trails. Having not looked at them yet, I assumed that a cooler would be more expensive than the 50-70 range mentioned. My funds aren't THAT limited, so I'll look into it. Any advice on where to look/what to get?

[TBYODA]

Build threads

[Trail X]

The search... this link should get you started in a search:

search.php?keywords=transmission+cooler&terms=all&author=&sc=1&sf=all&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

[navigator]

in your situation you can likely get by ok without one.
They are cheap though, do a little searching of the builds and modification threads and you should find some good write ups. Seems like mine was under $60 for the basic kit. I have since then bought one of those Hayden fittings that should keep me from having to cut the transmission line.

http://www.amazon.com/gp/product/B000EP ... UTF8&psc=1

[AGENT SMITH]

Thanks for all the input. I will continue drooling, researching, and planning.

[navigator]

just an update on 32s and 3.42 gears, I went on a trip last week and on the way home on the interstate roughly 90 degrees running 75 I got up to 228. Once it hit 228, I turned off the AC and rolled the windows down and it dropped down to like 215. I was running behind so I couldn't really slow down a lot so I turned the heat on and let it blow out the passenger side. Doing that I was able to get it back under 210.

I temporarily installed my cooler today, on the short trip I ran a little while ago it seems to have dropped my temps about 20 degrees. When I swap in my new front diff I'll do a better install and try to write something up.

[Moots1288]

228 was the water or Trans?

Sent from my SPH-L720 using Tapatalk

[navigator]

Trans was 228.
Coolant was 210 if I remember correctly.

[TPuls]

I'm running 32's with the 3.42 and offroad just about every weekend. I pull a travel trailer a lot of weekends as well...3200 lbs dry then add supplies in the TT and a family of five with two dogs in the Envoy. I'm in the mountains in Northern Utah as well. Definitely not optimal but it gets the job done. Where we typically go it's just over an hour from here. Interstate for 20 minutes then climbing up the mountain after that through the canyon. My temps get up there a bit. I'm running a cooler and I honestly haven't looked into any upgrades (if there's even any or if a cooler is a cooler, i'm not smart on these and haven't bothered to research) because my car has run on the warmer side for years. When it was stock, towing, not towing, it didn't really matter, and it does now. Anyways, just my .02.

[v7guy]

Also keep in mind that you may want a thermostat on the cooler to keep from over cooling in the winter, I know Moots couldn't even get up to operating temp in the winter and we ended up blocking off the cooler on the highway a couple times.