MuskyHunter

I'm looking at a new 07' Tahoe with the 5.3L My 00' Tahoe hunts for gears a lot so I suspect it has the wrong rear end gears to be pulling a dual axle boat that weights approximately 4000lbs including trailer. Does anyone know how to translate the code in the glove box to determine what gears I have now?

What gears would be best for towing 4000lbs? I believe the only options are 4.10, 3.73, 3.42 and 3.23

Thanks.

deejayrock

Musky,
I'm not sure how to translate the codes, but I myself have a LT3 w/ 3.73 and it pulls our 21' Boat w/ dual axle trailer as well as a 24' enclosed car hauler and you can't even tell there is something behind you. The truck also has tow mode.

Also, another note, on my truck I have navigation/rear view camera and I can attach my trailers w/ out any help and having to keep getting out of the truck, I can see my hitch on my navi screen=). It also comes in handy when backing the truck in the garage w/ the sensors.

Hope this helps somewhat.

ZX1100F1

Here are the option codes found in the glove box for each corresponding gear ratio:
3.23 = GU5 (Std 2WD w/4.8L)
3.42 = GU6 (Std 2WD w/5.3L)
3.73 = GT4 (Std on 4X4, opt 2WD)
4.10 = GT5 (Opt 4X4)

Any engine and ratio combination on the 07 Tahoe can handle a 4,000lb trailer.
In theory the higher ratio's (lowest numerically) provide the best fuel economy however that is not always the case, the older 350ci engines were very RPM (speed) sensitive and ran most efficiently at RPM's below 2,000 the newer 5.3L Vortec power plants have a much broader power-band and run efficiently across a much wider RPM range. In other words gear ratio’s do not make as noticeable a difference in MPG now days as they once did, but they can improve performance while towing or even accelerating in city traffic on the way to work.

My Tahoe is a 4X4 with the 4.10 (GT5) ratio, I pull a 23’ boat that weighs about 5,200lbs trailer and all, I live in mountainous terrain at high elevations (4,400ft), on a recent trip to Idaho I pulled the boat over 1,200 miles round trip and averaged 12.5 MPG while towing and was also able to do at least the speed limit on the steepest hills (and there were some very steep climbs) with 4 adults and our gear in the cab.
Another thing that I’ve noticed when pulling a load with a 4.10 equipped Tahoe vs. the 3.73 model is that the vehicle has an easier time holding overdrive (4th gear) on the highway (always engage tow/haul mode when towing).

If you live in the flats then the 4.10 gear (assuming 4X4) would not be necessary and could also be hard to find.

Keep in mind that the difference between each ratio is 1 tooth on the pinion gear which amounts to about 180 RPM difference per ratio on the highway.

jasonw75

My 07 LTZ has 3:73 gears and I wish I had the 4:10. How hard is this to change? My trailer weighs around 5,000 lbs fully loaded and the truck seems to struggle.

ZX1100F1

If your Tahoe is a 2WD then you just have to change the rear gears and get a new VCI from Techlink, the gear set costs about $250 its the labor that going to add up big time for this job.
If you have a 4X4 forget it, the cost to change out both ends would not be worth it at all.

The reality though is that even if you were to change the gearing you probably won't notice much of difference, a 5k lb trailer is a good load for a 1/2 ton suv and will slow you down a bunch.

jasonw75

I needed a truck and couldn't wait for the 3/4 ton Suburban. As far as I know it's still not out yet. I haven't heard too many good things about the new 6.2L. Does anyone have one and what do you think?

ZX1100F1

The 2007 suburban 2500 has been out for a couple of months now with the new LY6 (6.0L) power plant.

What bad things have you heard about the new L92 (6.2L) engine?

jasonw75

ZX-
Thanks for the update.. I called my dealer after seeing your post and they said the 3/4 tons still aren't out and GM was thinking about not making them until '08. I have to say I believe you over them, but find it odd they don't know they are out yet. Is the 6.2L an option for the Suburban or is that only in the "luxurious" Denali and Escalade. My dealer told me they were putting the 6.2 in the 3/4 tons not the 6.0... Again I trust you over them. Have you heard anything about a diesel for '08. That is another thing my dealership keeps telling me. I live in Michigan and have a buddy that works at the proving grounds in Milford and he says they have them there. Any insight would be appreciated. PS. Your input in this forum is sincerely appreciated. You Da Man!!

Jason

jasonw75

ZX

I forgot to tell you what bad things I've heard about the 6.2L... I basically heard it doesn't have the torque of the 8100 it is replacing. The other bad thing is if I understand you right they don't offer it yet in the Chevy.

ZX1100F1

I thought that you had heard of some sort of reliability issue with the motor, glad that that is not the case.
The 8.1 was a torque monster at low RPM's but the 6.2 runs very well and generally outperforms the 8.1 in all other areas.
The 8.1 was built upon the dated 454ci that had hit the end of its useful life cycle.
The 6.2 is only available in the Denali and Cadillac right now but look for it in the 2500 Sub next year, the 6.0 liter is available in the 2500 Suburban’s right now and will be available in the 1500 later this model year (2007).

There have been a few Duramax (255-300hp with 4-speed and 6-speed non-Allison transmissions) Suburban mules around for years but GM has no plans to roll a diesel Suburban into production, they don’t feel that the market is there for this product, 68% of Sub drivers are primarily women and they don’t like pumping diesel, not to mention the price of diesel fuel at the moment, it’s more expensive than regular unleaded in much of the U.S right now and the market is trending toward leaner machines as well.