you can take the rear end out and count the teeth on the gears, lol

 

I'll PM it to you. I'm about to go for a ride with 4.8T who has 3.73's and see what the diff is.

I took the highway home and it turns right about 2050rpms at 70 and 2250 at 75. If I remember my 01' silvy right it turned 2000rpms at 75mph. It had 3.42's.

 

I also wonder if you torque converter is locking up...right now...mine does not....on purpose and I run 100 to 400 rpms higher without the torque converter locked.

A good way to tell if its not is...drive down the highway steady while still steady on the gas, gentally press the brake pedal until it starts to brake and let off....it should sound like its going out and in gear.

 

It locks up just fine. It only has 1,000 miles on it. LOL

 

It does jump off the line pretty hard for its size, that makes me wonder too.

 

Isn't there a way to tell by counting revolutions of the drive shaft or something. I can't remember right now but there is a way to tell...without removing the gears.

 

I ran the vin and it shows it to have 3.42's. Not sure whats going on, maybe a mistake on the gears or converter not locking. Thats all i can think of at the moment.

 

The convertor is locking up just fine. A second look at the window sticker it doesnt say what ratio it has, just the sticker in the glove box. I need to find someone with 4.10's on a simular ride to compare.

 

My '02 Yukon has 3.42s. At 75mph, the tach sits at 1900rpm (265/70/16 Firestones). At 70 mph, RPMs are closer to 1800. At 90mph, RPMs are at 2500.

Just thought I'd throw $0.02 at ya'll for comparison purposes. BTW, my Yukon hauls from a stop for it's size... enuff to turn 15.9s 1/4 mile at about 80-sumthin mph (bone stock).

 

I worked at a dealer that would swap em to make a sale go thru. Not legit , but it is a stealership we are talkin about here. Jack it up. put a piece of tape to mark the tire. mark the driveshaft and spin the dshaft until the tire makes one revolution. the amount of turns is your ratio. IE if you rotate a little over 4 times , you have 4.10s. If it spins about 3.5 times you have 3.42s. You get the idea.