My 03 trailblazer ext is really acting up..when I first start it up I have all gears but in ten seconds all gears stop .so if I turn the truck off wait for a minute or so start it back up I have all gears again for 10 more seconds then all gears gone .it just keep doing that over and over .please were should i start first

Stickied: Glovebox guide to 4L60E problems while on the road - Chevrolet Impala SS Forum : Chevy Impala SS Forums[/QUOTE]

 

@Mrwayne79 how many miles on it? Did you check the fluid?

 

The transmission filter is plugging up while running. With the vehicle running the transmission pump is pulling fluid thru the filter and allows the car to move. However. When the filter gets plugged up it stops moving bc the pressure is low. Temporary fix-replace filter but most likely the trans is coming apart and needs to be rebuilt/replaced. When you turn the car off all the debris in the filter falls back into the pan allowing fluid to be picked up by pump. Thus the continuous cycle you experience.

 

Just had this happen on my 08 Avalanche. 2 HR drive, 70 mph, suddenly revving in 4th. 1st and 2nd normal, shifts into third slipping bad, finally shifts in to 4th at 4000 rpm, slips bad. 2500 rpm in 4th is 45 mph. Seems sudden and unusual that the clutch would fail at steady state 70mph.

 

My thoughts exactly because same thing happened to me going on the interstate started losing overdrive and then it went away and worked fine. now 4th and 3rd is gone or it feels like it's revving in neutral. If it was clutch packs it seems like it wouldn't go in and out of gear it would just lose friction all together. Did you figure out what was wrong with yours? Mine is a 4l60e in trailblazer.

 

Ran a pressure test on mine, 140 psi in 1st and 2nd, 80 in third and fourth. Did not take it apart to see what the issue was but most likely either input shaft seal or apply piston seal, both require trans out so bit the bullet and put in reman trans from powertrain products. (ouch!).