Hi Scotty: I have a 2003 Chevy Suburban 1500 LS with 280.000+ miles on the body and about 1700 miles on the rebuilt Powertrain 5.3L Vortec Engine. Transmission is unknown how old. I bought this from a private party last year and had to replace the engine last November.
The issue I am having is , loss of acceleration the transmission is having more harder time getting out of 1st and may or may not be getting out of second Rpm want to stay below 2000 when attempting to go 60mph.
Before this I changed the O2 Sensor Bank 1 Sensor 1 after replacing that it seemed to do better and then shortly after the transmission issue got worse it's had a hard shift issue in first but then does okay once in second and so on but now I have loss acceleration and am scared the transmission may be going out what sounds like the major issue here this is a Automatic Transmission a 4L60E.
The only light coming on has been service brake system which reads out in those letters in the instrument panel and ABS light / Brake light.
Thanks Cliff
transmission might be fine. Fix the engine first. Test fuel pressure, check exhaust backpressure as Chuck suggested. Run a professional full diagnostic scan.
Oh I hope the engine is okay because I just had it put in last November
There are many things that can cause the engine to bog down, from hinky fuel injectors to a clogged catalytic converter and may things in between. It would be helpful to not only scan for codes but also capture live data for analysis.
The transmission may well be a separate issue. When is the last time it was serviced? Is there sufficient fluid and what is the fluid's condition?
I haven't serviced the transmission and it is unknown before. We were taught not to touch them, but I've seen your videos since then 😄 so far it is full and is a light dark like red when dip stick is checked. New fluid had to be added due to spilling out when motor was put in so it does have some new fluid but nothing else has been done to it.
The transmission problem could be just shift solenoids but it would take a high-end bidirectional scan tool to make that diagnosis.
I will most likely have it checked by a mechanic then.