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'04 GMC Envoy Transmission Problem or....?

Mileage: Just hit 200k

Hey guys I’m having issues with what seems to be the transmission but to me it is unclear, and seems just as likely to be something else.

When giving the car gas, instead of accelerating it REVs high and makes a fast clicking/almost knocking sound. It feels as if it is not engaging into gear, when i let off the gas sometimes it will engage into gear and then when time to shift again, same problem. When first starting the car, it seems completely fine until i get up to about 30mph+ and can’t seem to get it to stay steady above 35-40mph.

The OBD codes are as follows: P0106, P0410, P0128, P2176, P0014, P0017, P0327. I’m really hoping that it is not the transmission and am actually looking to replace the MAP sensor first. None of the codes seem to have anything to do with the transmission. Is anybody familiar with these codes and these issues to know if any of the codes can be throwing this sort of symptom? I will also mention that when i bought the car recently, it had been running with very low amounts of oil and the engine had been knocking, when i added about 6 quarts of oil, there didn’t seem to be any issues at this time.

Transmission fluid has been checked and is good.

P0106- Manifold Absolute Pressure/ Barometric Pressure Circuit Range/ Performance (MAP Sensor??)
P0410- Secondary Air Injection System
P0128- Coolant Thermostat (Coolant temp. below therm. regulating temp.)
P2176- Throttle Actuator Control System Idle Position Not Learned
P0014- B Camshaft Position Timing Over- Advanced or System Performance Bank 1
P0017- Crankshaft Position, Camshaft Position, correlation Bank 1 Sensor B
P0327- Knock Sensor 1 Circuit Low Bank 1 or Single Sensor

6 qts low? now thats not good. holds 7.5 qts if i recall. i bought an 05 trailblazer with a bad trans but thats a small sample size. 4l60-e is a common trans. fairly cheap used.

Heck of a list! I had the po128, A new thermostat solved the problem Kind of a pain, as it is at the bottom of the engine and if I recall correctly I had to remove the alternator., kind of expensive as you have to buy the thermostat in the housing. $60 or so. is an excellent resource.

Actually, a transmission at this point might be the lesser evil. 6 qts low on oil is not good. I assume this is the inline 6 cylinder engine in your truck? The engine could be damaged from low/poor oil condition and I could see a number of those codes as a result. Have the codes been cleared since the oil level has been restored?

Extremely low on oil, possible running in open loop due to chronic low engine temp, engine knocking…I hope not but this engine could be seriously damaged…

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Correct, yes it is the 6 cylinder and my mistake, the codes hadn’t been cleared but i never used the tester until after I added oil and then waited about a week or so before i started having these issues. I just cleared the codes and ran the tester but am not getting any codes yet. I cleaned the map sensor and it seems to have fixed the engine surge and the rough idle but not the issue. Im thinking it IS the transmission but it also probably does have some serious engine damage because of the lack of oil. I did find a leak so i don’t know how long it ran with about only a quart of oil or how quickly it lost the oil, i have no way to contact the previous owner but I’m thinking that at this point I will just consider the truck totaled.

I will sit on the truck for a little while though, if anybody else has any insights that would be a great help. And thank you everyone for their time and insight

It could just be the shift solenoids are sticky. I would throw some stuff in a bottle at it before throwing in the towel. Maybe something like TransX or similar to see if they clean up.

Thank you, I will give this a shot. When i was researching the problem the solenoids have come up as a possibility numerous times and is the #1 common issue for envoys/trailblazers and is also relevant to the p0014 and p0017 codes. So thank you for bringing this up.

My reading was the engine was low 6 quarts in motor oil, 7 quart capacity, the trans is a 12 quart capacity I believe.