My dad wants to buy a 2007 GMC Sierra and we found one at a dealer and it has a 3.73 Gear.....Is that the best gear for towing or should we get a 4.10?...it will be use for Commercial RV Transport and most of the trips are 850miles and up...

Thanks,
Lenin

Diesel is only the 3.73, I run over 24k GCW with the toy hauler, pulls just fine.

Ok, I found my answer....Thanks for the help..

Put it in Drive and use Tow/Haul mode. The tranny knows when to downshift out of overdrive.

Diesel is only the 3.73, I run over 24k GCW with the toy hauler, pulls just fine.

Are you sure about that? My 05 came with 4.10 when I bought it new, and I'm 90% sure my 06 also came with 4.10

As for the original post.... 3.73 should be fine especially on the highways, plus it will give you better fuel economy than the 4.10s

05s came with the 4.10.

06 and newer is 3.73 only.

Thanks. I wasn't sure on my 06

05s came with the 4.10.

06 and newer is 3.73 only.

Duramax has never been available with 4.10...3.73 only.

Duramax has never been available with 4.10...3.73 only.
You could get 4.10 with a duramax

Duramax has never been available with 4.10...3.73 only.


X2...... not in the 2500 or the 3500...

I know for fact my 05 Dmax has 4.10's

I know for fact my 05 Dmax has 4.10's

Not from the factory...EVER. Go look in your glove box and you'll see a placard that has all of the build codes and you will see GT4...which is a 3.73 and the ONLY available axle that has EVER been available with a Duramax. 4.10 was available with the 8.1 and 6.0 gas engines, but NEVER on a Duramax...sorry, not trying to be a butthole, but I am right. Send me your VIN and I pull a VIS on it and show that it's a 3.73.

Duramax has never been available with 4.10...3.73 only.


This is what I was always told as well. NO 4.10 ever was available.

Neeeeeeeeeeeeeeeever was there a 4.10 in a D-Max from the factory.
Geno