chevyalltheway

I have a 2002 z28 and the past week while i was on the freeway, i slammed on the gas to speed up, i heard a rumbling sound and while i was pressing the gas, it was just forcing the car. I was going about 50 mph and nomore?. I thought i messed up the transmission but it still drives and reverses good?. Its automatic but now i have to have it on 2nd and not on D (DRIVE). so im like driving it forced but tops out at 50 mph. SHould i rebuild the whole transmission ? Or is it just some gears to be replaced? I went to a transmission shop and charge me about 1200 to rebuild it. Need some advice?

Injuneer

Scan the PCM for codes. There are some codes for the transmission that do not turn on the SES light.

Moving from "Exhaust" to "Drivetrain".

JakeRobb

You haven't described the problem very clearly. At this point I'm not sure you should be sure the transmission is the problem.

Is your SERVICE ENGINE light on? Have you checked for diagnostic codes? When you try to accelerate, what do the engine RPMs do? Where is the rumbling sound coming from?

$1200 is a very good price for a competent rebuild, if that's really the work they're quoting. It's rare to see that quoted under $2000, especially if it includes removal and reinstallation.

chevyalltheway

Yes the service engine light has been on aince i bought it. But it always ran smoothly and strong. Until last week when stepped on it. Its like a rattling sound under the car, it sounds like the catalycs around that area. And no i havnt checked for diagnostics codes. Yeah the shop i went too told me it would cost around 1200 to rebuild it plus 3 year warranty. So i should get it diagnosed first to see what the problem really is?.

Injuneer

You should have scanned it for codes before buying it. Still a good idea today. You can pull the codes with a very inexpensive OBD-2 code scanner.

Are you leaving it in 2nd because it won't shift any higher, or because that's the only way to raise the RPM high enough to generate enough power to move the car?

PS: What was the resolution of the problem with coolant in the PS reservoir? Spent a bit of time trying to help you, but you never followed up on that thread.

chevyalltheway

I can get it scanned in autozone for free cant i?. Yes i have to have it on 2nd because it wont shift into gears nomore. Ohh yess i got it working, i removed the original ps cooler and replaced it with an aftermarket one. It doesnt leak anymore.

Injuneer

I would assume you have a nearby auto parts store that will scan for free. Unfortunately, they don't always provide you with the correct info. In any case, write down the EXACT codes. They will give you a generic description, we have access to GM codes lists specific to your year and engine, diagnostic procedures, etc. I wouldn't rely on an auto parts store, but it's your car, do what you want with it.

chevyalltheway

Okay ima do what you said and get that code scanner.I will keep on updating once i get it.

chevyalltheway

I just got an obd2+abs diagnostic tool from sears and it shows me "P0134, HEATED OXYGEN SENSOR (HO2S) CIRCUIT INSUFFICIENT ACTIVITY BANK 1 SENSOR 1?. what does it mean

chevyalltheway

It also shows P1637 General L- terminal circuit and P0102 Mass airflow (MAF) sensor circuit low frequency?.

Fatdog2

I would check the coil.I think when the coil goes south it can cause some issues I think.Hope this helps.(it's kind of a chain reaction thingy).Just thought I would throw this in there cause I've seen this before somewhere.hope this helps.

Injuneer

P0134 = indicates the drivers side pre-cat O2 sensor is not working. It is stuck at the bias voltage the PCM provides, and is not moving out of that range like it should. The PCM will ignore the O2 sensor readings. Could be a loose or corroded connector, bad wiring or a faulty sensor. Should not affect the trans. May affect engine power.

P0102 = the PCM has determined the mass air flow sensor is providing an incorrect (too low) reading by comparing the MAF sensor air flow reading to an air flow calculated using the speed-density method (relies mainly on the inlet air temp, manifold absolute pressure and volumetric efficiency tables). Bottom line... MAF sensor is not reading correctly. May be as simple as needing to be cleaned. Or the sensor could be faulty. Should not affect the trans. May affect engine power.

P1637 = a problem with the circuit the PCM uses to activate the alternator. Could be a problem with the alternator, or could be a problem with the wiring. I'm not real familiar with this because it is only used on the LS1 engines, not the LT1. I don't think this would affect the trans.

What did not appear are any codes related to the transmission, like faulty shift solenoids, components slipping, excessive fluid temps, etc. When those codes set, many of them will inhibit converter lockup, or even how many gears can be selected. Those codes are in the P0700 range.

I would have it checked for a plugged cat. They can pull the O2 sensor and connect a pressure gauge to the exhaust pipe to check.

chevyalltheway

Okayy so do you think because of those sensors, my cars not able to shift into gears??..

Injuneer

I can't find any indication that those codes will directly alter the trans performance.

In any case, fix the problems that you know about. The engine will run better in the long run. If you can only get enough power to run the car with moderate RPM (if you have 2.73 gears, your only at 2,870 RPM at 50 MPH in 2nd gear/3,400 w/ 3.23's) and high throttle, you may not be reaching the RPM and line pressure that the PCM is programmed to shift the trans at.