2000 Blazer LS, 4wd, 4dr, automatic.
Bought the car in the spring, haven't been using it much, maybe 2000Km.
Know very little about cars till the last few weeks., Google has been my friend.


Greetings,

After changing the transmission filter, transmission only seems to work (kind of) when overfilled and the rear of the car is raised. Is it possible for the pump to loose its prime? Wondering if I have an air bubble in there somewhere. Planning to remove the pan again and check on the filter tomorrow.

The Story so far:

Transmission was working well, oil passed the 'paper towel test', but figured I'd change the transmission filter anyways, as I seemed to be doing everything else.

Drove the front of the car up on wooden bocks, about 12-14 inches high. Chocked the wheels. Put the car in neutral, released the Shift cable from the transmission control lever stud and oil pan clip. Removed the bolts to the transmission, drained the oil, but couldn't get the darn pan off! The cross beam was in the way. Called it a night.

Next evening. Having Googled the problem, I found a suggestion to remove the two bolts holding the transmission to the cross frame, and jack up the transmission a few inches. This allowed me to wiggle the pan free. I removed the old filter, and used a small sharp screwdriver and a mallet to warp and then remove the seal. Put in the new seal. I cleaned the pan, and gasket surfaces, and coated them with clean oil. Put the new gasket on, the filter into the bottom of the pan, and put the pan back on. Tightened all bolts, and put back the Shift Cable.

Drained the Transfer case (which seemed to have almost no oil in it), and filled it up. (The 4wd is not currently working, do to dead electronics. <sad>)

Lowered the transmission, and bolted it back down.

Filled the transmission with oil, roughly what I had drained.

Turned on the engine and went through the gears: Nada. It would not go into any gear. Googled the problem, which generally said it was low on oil. Added more oil. Still no gears. Added more oil. Still no gears. Called it a night.

Decided that maybe the pump was not priming itself for some reason. Undid the top radiator line of the Transmission oil. Ran engine: no Oil flowing.
Lowered the front of the car. Again, no gears, no oil flowing. Raised rear and put wood blocks under them (12-14 inches). Left it for the night, oil line at radiator still off, and filler tube open.

Next evening, I ran the engine: oil is flowing! Attached transmission oil back to radiator. Ran through the gears; transmission is going into each gear, but with a clunk! Ran car for awhile, each gear, brake on. Engine off. Lowered the rear, siphoned out some of the extra oil through fill tube. Car will no longer go into gear! Raised rear, added oil, car goes into gear! Left engine running, lowered rear, move up and down the driveway. Car is going into gear, but there is almost no power, transmission seems to be a slipping a lot. Go back and forth in driveway perhaps a dozen times, the clunk goes away, things seem to get a little better, but still very bad. Check the oil, (engine running) and see there is still far to much. siphon out oil down to proper amount. Car no longer goes into gear. Raise car, car will go into forward (kinda), but not reverse.

So, have a somehow destroyed my transmission, or have I missed some important step? I've come across articles saying "don't disconnect the transmission line to the cooler and use it to pump out the oil, as it could cause you to loose the prime in the transmission pump", but I haven't found anything that tells me how to Re-Prime a transmission pump. Can one? Does one even need to, or are the self-priming? (Sounds like they are).

Any advice would be much welcome. Thank you.

 

I'm wondering if you got the filter fully seated into the seal up in the transmission. If it were leaking by at the seal, it could cause the condition you are currently dealing with.

Did you replace the seal up inside the transmission that the filter seats into?

 

I did. Removing the old one was not easy. Glad the Haynes manual had a photograph showing how, or I'd never have dared use that much force. Even with a dab of oil, putting in the new one required the use of an old socked and mallet to tap it into place. They fit rather snug. I can't image how it would come loose, or ever come out with the filter.

I did a dry test fit with the filter & pan and it felt like you couldn't attach the pan back on unless the filter was just in the right spot. However, maybe I just got unlucky, and something went wrong. I'll try again tomorrow.

 

So, I drop the pan and remove the new filter. Once again, I compare it to the old filter, going so far as to measure it with a caliper. Except for the molds used to make it, identical.

Rather then just putting the filter in the bottom of the pan, I try and push it up into the seal. Doesn't go very far, less then a 1/4 of an inch, and I could never get it as snug as the old one, which took a bit of twisting to get it out. Put the pan back on, and added oil. Transmission still not working.

Went out to another parts store and got a second new filter. Interestingly, they asked me a question that the first store has not: Shallow pan or deep pan? After reading the brief descriptions between the two, knew I had a deep pan. Compared the new 'deep pan' filter to the old: The filter is the same basic size and shape, just slightly thicker and overall about 5/8" 'taller'. This means that rather then going in less then a 1/4", roughly half way into the seal, it fits all the way through the seal and then some.

Installed the new filter, and SUCCESS! Transmission is working again.

Guess the moral is the old story of always make sure you get the right part. However, since my first new filter was identical to the old (which worked), and was given to me by the clerk at the parts store, not sure how I could have known better. I'm thinking that that maybe the old filter was put in with a little RTV, or something, to seal it up properly and keep it snug.

 

I recently had a similar problem though I thought the job went well and without a hitch.
But mine was then slipping in drive after the oil and filter change. It ran fine in all other gearsincluding reverse.
I took it to the transmission shop and then was told I screwed up by not first removing the battery cable when doing the job. I thought they would make some small adjustment for a nominal fee. I had to pay them $350.00 for what ever they did to get drive working again. I think I got totally hosed!!
This all makes no sense to me. I have done this same job before, even on Blazers and never unhooked the battery and never had a problem thereafter.

Can someone tell me really why the battery cable should be unhooked when you are only removing a pan?? Is this what caused my problem??