how do i find out what rear end gears i have and what tranny ive got. I have a 2001 gmc sierra 5.3L V8 Z71.

 

4l60e tranny and either 3.42 or 3.73 gears. Check the RPO codes in your glove box, should either be GU4 or GU5 i believe.

 

what trucks came with the 4l80e.

 

and with this info what is the best thing to do to protect my drivetrain. I have Lts, magnaflow cat back, K&N, nelson tune, and a comp cam coming soon. I am very concerned about my drivetrain holding up.

 

70mph turning 1900rpms is 3:73's(correct if i'm wrong),, and a billet or vette servo and a shift kit and the biggest trans cooler you can get pretty much

 

do any of you think it would be wise to get a new transmission form some one like finish line, IE the 4L60E-3. and maybe even a LSD?

 

Shift kit and servos will be all u need thru 400rwhp...and u wont get close to that without at least heads and a blower. Of course, driver style plays a large part...just dont tune it at the ragged edge. RR end prob good insurance against toasting ur tranny...def cheaper! Again, depends how ur drivin, how much u go to the track. R/

 

I do not get a chance to go to the track that often, i would say like 3-4 times a year, this will be a DD. I live in a city. where is a good place to find more info on shift kits and servos, what price range are we talking about.

 

vette servo is like 20 bucks billet is like 80 bucks... you can find them on transmissioncenter.net

 

for the hd-2 kit, billet forward, wette servo, billet 4th, and the 2 accumalator, and tranny filter i was just over 300 as i recall......
this is waht built 408 recommended and what i got..... minus the cooler... which is on the way.....
"I would recommend the transgo hd-2 kit, aluminum 1-2 accumulator piston, billet forward accumulator piston, corvette 2nd gear servo, and billet 4th gear servo, and a large cooler. "