Patrik Stufflebean

I am almost at my wits end! My suburban is a Z71 with the 5.3L and it is not wanting to shift. I have to take it up around 4K, then let off the gas to get into second and third. It then will not go into 4th. It usually take several attempts to get it to shift, but when it does, it goes smoothly without hesitating or catching. It will also occasionally slip out of third at 50mph. I have had trouble with the speedometer since I've had it, by that I mean it just randomly drops to zero. I should also mention it is very high mileage, 275,000. Other than this issue, it runs extremely well so I'd like to fix it if the money is right.

So far, I started atthe transmission and replaced the shift solenoids. No metal shavings in the pan and the fluid was still full and wasn't discolored. I then replaced the throttle position sensor and mass airflow sensor, since the tps made sense and the maf sensor threw a code. No success. I have traced the wiring for all 4 ABS sensors, the transfer case and transmission, and the entire engine compartment. I have pulled every fuse and couldnt find any that were bad.

I'm thinking the rear shaft speed sensor....any ideas are welcome!!

Suburado5.34L60E

I would look into your speed sensors on your transfer case if its 4x4, if so then also look into the question of if your tcase is any good or not, I've got an 05 suburban 4x4 4l60e 246 tcase, bearing burnt out in the tcase and started wearing into the speed sensors, trans wouldn't shift past 2nd gear no matter what I did, replaced tcase and of course new speed sensors, problem solved. Hope this helps someone thread looks a little old