transmission noise

I've got a 1990 buick lesabre with the th440 t4 transmission. Whether is in gear or not, moving or not, i can hear a strange noise coming from the transmission. Its very hard to describe, its sounds like a cross between a grinding/chattering noise. It it loudest when the engine is running at 1500 rpm. I changed the fluid, but the noise didnt go away. I then powerflushed the transmission, changing 100% of the fluid. Then noise got quieter after this. I have no idea what could be causing this. If anyone has any ideas, id really appreciate help. This noise is extremely annoying and its embarassing to pull up next to people with it. Thanks, Matt.

Its your oil pump in the transmission, most likely.
There is not much you can do except replace it. If you remove the trans , then remove the torque converter and the pump is just behind the converter.

Usually when they get that noisy, they are destroying themselves internally and pumping lots of aluminum and steel filings in the oil throughout the trans. This will ruin all the internal O rings causing them to leak and cause slipping and burned clutches.

So, if you are going to pull the trans to replace the pump, rebuild it all to avoid a future breakdown.

how hard do you think it would be to pull the trans? I'm an assertive do it yourselfer, and really do not want to pay someone a grand to pull this thing out, as a new trans is going to be expensive enough

how hard do you think it would be to pull the trans? I'm an assertive do it yourselfer, and really do not want to pay someone a grand to pull this thing out, as a new trans is going to be expensive enough

lift the car, support the engine in the bay from going any lower, remove the wheels and axle shafts, remove the engine cradle from the unit body, unbolt the tranny and lower it - piece of cake!

rebuilding a 440t4 (aka 4t60) costs over $1100 to do correctly...on a car that old, not worth it, your best bet is to contact people that happen to have 1990 440T4s that run sitting around (hint hint)

that doesn't sound too bad. Whats the best way to lower the trans out of the car once its unbolted. I'll be doing this in my driveway, so a reg. trans jack wont fit.

You can use a regular hydraulic trolly jack on wheels. Just place a piece of plywood between the transmission pan and the jack. Get a couple of buddies as its heavy, at least 150 lbs. It is not a particularly easy task in a driveway. Perhaps call around and see who can do a re and re. About $250 should take care of it.
Also, if you do get a used trans, there were about 30 different variations of the 440 trans, with differences in torque converters, final drive gearing, valve bodys and shifter linkage. Its best to rebuild the one you have.