GM Truck Club Forum banner
1 - 4 of 4 Posts

· Registered
7 Posts
Discussion Starter · #1 ·
New member here.... name is Mike... i just recently blew the rear end in my truck...

code in the glove box says GU6- which is a 3.42 ratio,

but the tag on my transfer case says 272 ratio... had the transfer case replaced about 6 years ago, have used 4 wheel in all modes without any problems since then... my question is why is the rear a 342 and the transfer case a 272?? and is this ok... ham is shattered, spider gears fell out when i opened it up, pinion also has chips along with planetary (sp?)

Thanks in advance..

· Premium Member
6,661 Posts
Transfer case gear ratio is totally different than axle gear ratio (or final drive ratio).
Think in terms like this: 2.72 is the drive ratio of the driveshaft from the T-case into the axle, the drive ratio out of the axle to the wheels (final drive ratio) is 3.42.

2.72 is a compromise, which in this case isnt bad, I'm guessing you use this truck for daily commuting along with weekend getaways. If your T-case had a ratio of 3.42 the truck would'nt be able to drive much faster than 70mph, and your mileage would be a lot less than it is. Unless you were running 37" or larger tires.
Check the splines on the axle shafts while you have it apart, these axles are notorious for chipping splines and twisting shafts.

· Super Moderator
1,646 Posts
And remember that the ratio posted on the t-case is the low range ratio. In high range, it's 1:1, so it's like it's not even there.
1 - 4 of 4 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.