Background: '99 2 Door, 2 wheel drive automatic Blazer with 150xxx miles on it.

I've never had any issues with the transmission, or even any signs that it could be a future problem until out of the blue it started acting up last night. It wouldn't shift properly, it would rev way too high and wouldn't change gears until I let off the gas and let the RPM's drop, then it would shift up. Also seemed to drive sluggishly up hills, as if it were pulling a boat or something. R, 1, and 2 all seemed to drive as you'd normally expect, and shifting between them wasn't harsh at all. No indicator lights came on, scanned it and no codes. Which, I would think, would rule out something electrical like a faulty throttle position sensor.

Now, I HAVE had what I believe to be a catalytic converter rattle for the last two or three months. Idling in Park would have a grumbling noise coming from underneath in the area of the CAT. My dad had a Caprice that he swore the tranny was going out of but turned out to be a really bad CAT, could this be the same? Or is it time to take this beast to a transmission shop?

 

Start with the simple stuff. With no check engine light, and no DTC's in memory, that takes a lot of possibilities out of the equation: All of the engine sensors and associated wiring, spark plugs, plug wires, cap & rotor, catalytic converters, transmission solenoids and their wiring, etc. The OBDII system does not monitor fuel delivery to the injectors, so it can't turn the check engine light on, or set a DTC, if there's a problem with it. That would be a good place to start looking. Check the fuel filter for restriction and replace it if necessary. Check fuel pressure and leakdown: key ON, engine off, fuel pump running, pressure must be 60psi to 66psi and must remain above 55psi for at least 10 minutes after the pump shuts off. Post your results.

 

Well, we have a new development. Went out to test these things ( just replaced the fuel pump a few months ago, with an OEM AC Delco pump, but was hopeful it could be an issue with fuel delivery) but I tried to move it into the garage and it wont get into any gear now, R, 1,2,3, D , nothing at all. Ding dong the tranny is dead.

 

Woops! Is the fluid level registering on the dipstick? Does it look brown or have that "burnt electric motor" smell?

 

Sorry it took me so long to get back to this. Was frustrated with it and decided to leave it alone for a while. So, i checked the fluid level, it's registering on the dipstick and looks only slightly low. I put what little I had on hand in, but could probably use another 1/4 to 1/2 quart I'd guess.

The fluid that was in there (showing on the dipstick before I added any) is nice and red, not brown at all and it doesn't smell burnt whatsoever. Also, I tried backing it out of it's spot and it had no Reverse, however, when I put it into Drive it moved. Unfortunately I can't tell how well it's going to move forward cause I can't back out of my parking spot lol. When in reverse it makes an unpleasant whining noise and it acts like it's in neutral.

 

Just replace the catalytic converter from Magnaflow Catalytic Converters at CWIK to get the best solution.

 

Any results for this thread??? I'm having same issue but my tranny isn't dead. I know I need to replace fuel filter because I dropped the tanks about 4 times....but the nut on the fuel line is stripped to **** and rusted on there. Gonna attempt to get it off again tomorrow.

 

If not the CAT, try the mass air flow sensor. It's a long shot but if it's dirty it can cause some weird things to happen. Could also be a shift solenoid acting up.