torque converter?

Are there any tell-tale signs that your torque converter might be going bad? My problem is... the other day some jerkwad decided to do a brake test a few cars up from me... we all ended up finding out how well our brakes are... I slowed down hella fast!! but right before I stopped (bout 5mph) it felt like my tranny was bound up a bit like there was lag and then it released (kinda a klunk) like I put it in nuetral... really weird.
Also when i'm at highway speeds and I just leveled off at whatever speed-55-60-70 whatever.. the rpm's drop about 300rpms it does this about 3-4 seconds after the rpms stay at one value... then when/if I accelerate by pushing down nicely/moderately it seems like it is a little sluggish. If the rpm's drop and i'm cruisin... I let off the gas just a bit and then accelerate the rpm's jump up the 300 that they dropped and the power is back.
No it isn't down shifting... already thought of that...
when it downshifts the rpm's change more than the 300 rpm drop...
A friend told me that was the torque converter "locking" or something to that effect and his car does that too.."99 grand prix GT"
also... there isn't any change with my boost readings..

the rpm drop is probably overdrive. the big clunk could be lack of tranny fluid when it is changing gears

It could be the torque converter slipping. The lock-up portion of the T/C is similar to a clutch and pressure plate set-up but more complicated. You have a wear surface inside a T/C called the cover, [it's the end that bolts to the engine]and a friction surface, just like a clutch. Once you reach a cruising speed the T/C will lock-up, meaning the friction and wear surface bind and turn together. As long as you remain at a steady speed and don't accelerate very hard the T/C will normally stay locked-up, but if that friction surface is worn it can slip as you give it gas, increasing the torque. That is when you see your rpm's jump up, if that is the case when you let off or decrease the torque, it will be able to lock-up again. As time goes by and the problem worsens it will begin to slip more easily, if this is your problem. Several things can cause this condition, but the two most common are the one I described (wear)and also fluid or line pressure could be low. First, check your fluid, park on a level surface and follow the directions in the owners manual for your particular vehicle. If your fluid is low, fill it up and test drive it. If the problem is still there take it to a good transmission shop (normally the independent shops seem to be the best bet, but not always). If changing the filter and fluid doesn't fix it, it is likely that they can adjust the valve body, increasing the line pressure and that will fix it many times. If it does, have him find out why the pressure was low. In a T/C, fluid is what forces that friction plate to lock-up or bind to the wear surface, so if the fluid gets low or the transmission isn't building enough pressure it will cause it to slip. In a manual transmission the clutch is forced to lock by the pressure plate, which is a series of finger like springs. When you push the clutch with your foot you're feeling the spring pressure in the pressure plate. If they are weak the clutch will slip, very much like yours is.
I wish you the best, I hope this helps, since this just started you probably haven't got anything serious wrong, but don't wait, if that clutch slips long enough you will burn it up (not good). Tom C.

Thanks TOMC... As for it "going into OD"... it was already in the OD... I counted the gears it shifted...That and if I hit the OD off button the RPM's REALLY go up there... not that i've done that or anything.... he he he... YAH if I scrounge up a few bucks i'll take er to a shop....

Thanks TOMC... As for it "going into OD"... it was already in the OD... I counted the gears it shifted...That and if I hit the OD off button the RPM's REALLY go up there... not that i've done that or anything.... he he he... YAH if I scrounge up a few bucks i'll take er to a shop....
Also... I had the tranny flushed bout a year ago and before and after that the fluid has been just fine.

Did you have the filter changed? You would never believe that such a small amount of crud could cause trouble!
You will be more likely to feel it go into overdrive. O/D is actually a 4th gear or 5th depending on your tranny, it's the highest gear, if you continue to notice, shortly after it goes into O/D you will feel the torque converter lock-up. It feels like another shift only very lite. The O/D button is there to let you lock out high gear when your going to be traveling at lower speeds (not something you're likely to need hehe ) around town, stop and go. If your shifter listed a 4th gear it would be the same as down shifting to 3rd to keep it from up shifting causing it to lug.
If your fluid level is good, raising the line pressure should fix it. Once you get a few miles on her, ya know? We all need a little kick in the pants after a while. TC
Don't worry til ya have too!

Excellent post there tomc2. :)

I just want to reiterate what he said at the end, that if the TC lock up clutch is going bad, you want to take care of that right away. The friction material will break down and find its way into everything else. Almost like taking teeth off a gear in a 5 spd and those teeth go around and take out all the other gears too ;) They will hopefully know when they find (or dont find) junk in the oil pan.

So how would I go about raising the line pressure?

hey man, i have the same probem with my A/T. apparently it is the torque converter, or in many cases like previously described, low fluid level. when you decelerate down to say 15mph for about 2-3 secs... and quickly acelerate again, does it feel like the car's almost rev-ing in neutral?... and then it takes about a second before you feel that torque actually kicks in and starts moving again.

couple months back i got it refilled up and changed the filter, it seemed to improve the problem however did not fix it.

i am saving up for a new torque converter from IPT and while i am at it... also upgrade the shiftkit and end clutch. hope this helps.