Converter problem?

[Money pit Beretta]

I have been getting what seems like a slip from 1st to 2nd. The shift lagged and the RPM would go to 3k. It "slipped" real bad once and I hit the rev limiter a few times(with help from my foot). I turned down the adjustable modulator and had no problems after that.
Do to a leaking gasket I changed the fluid/filter and cleaned up the gasket. On the test drive it was back to the "slip". Driving today I backed out and drove for a few blocks. Got stopped at a light, when it turned green I hit the gas normal. Nothing happend so I let off to try again. Fear took over as people were waiting(well that was part of it). Got the RPM up to 3k and I was moving at 20mph. Across the main road I hit the side streets to check things out. Pulled it into low, driving slow for a few blocks and it seemed fine. After work it happend again.

I can say that it seems like I have a clutch and I'm not letting it out very far. Feels like only a 1/4 or less of the power is making it to the ground. As I kept driving it went back to just the "slip" in 1st to 2nd with all other gears normal.
Aamco is the only place I can think of to take this car to. Anyway the back ground on the trans is that it's a two year old rebuild and an aftermarket converter. I'd have to find my "new car" topic for better info. You know me and the "search".

Oh yeah, fluid looked normal and the metal on the pans magnet was also normal.

[1988GTU]

Can you verify the trans fluid temp? (scan tool) I am thinking the forward band is the culprit.

[whiteretta]

I can't remember, does the shift improver kit help with this? I highly doubt it just, just curious. I know it cures many constant symptoms, but I don't remember what they all are.

[Money pit Beretta]

Not sure if my scanner is able to read the trans temp. I know for sure it doesn't read ABS codes(it's a bit basic in other words).

Still think it's a power transmission problem and not a shift problem. The power is coming from the engine and somehow not making it to the road.

[3X00-Modified]

Which could lean towards many of things... a torque converter is made to slip, it's fluid coupling so if something is going bad in it you will get consistent high slipping feeling, or chatters and inconsistent power over the whole rpm range. It wont just rear it's ugly head when it shifts. If your only getting this issue upon shifting I'd point at the valve body acting up, OR the clutch packs themselves loosing initial bite and slipping during the shift.

The only time I've ever felt a converter fail is when it was in lockup, it would go into TCC and when you just roll onto the gas the RPM's would typically stay steady and rise in relation to the MPH... but with the TCC clutch failing the RPM's would slip up about 200-300 rpm when you just touched the throttle. TCC engagement is the only time there is a mechanical power transfer going on in the torque converter.

[Money pit Beretta]

That clears things up. I was thinking the fluid coupling was going wrong do to breakage or stalled impeller. Many crazy thoughts come about when the "unknown" happens.

Anything that I can try without opening it up? I'm sure there is nothing though. Trick Shift LOL? More of those crazy thoughts!

I was told and never use anything but ATF(no stop leak or gimmicks). The only time this trans had O'reilly off brand is for the break in. After that it has been Valveoline Dex/Merc(two changes of fluid/filter). It was recommended that a trans cooler should be put on, but I never got to it. Outside temp at the time of the major problems was 27F, so no problem there. Just FYI.

[whiteretta]

I don't think any new fluids will help, but if you'd really prefer to switch in the future, Dexron VI is known to lower trans temps. Just for future reference.

[1988GTU]

Swapping out the current trans fluid with Type-F fluid ***might*** bring back the trans for a short time, but it will not fix it.
You dont have to flush the trans 100%. A spill and fill should do it.

At this point, it might be worth giving it a shot.

[ifixalot]

Are you sure the trans fluid was/is full?
Checked at full operating temp with the engine running in park?

[Money pit Beretta]

I'll keep Dex 4 in mind(thank you).
It sounds like it's going to have be put in the shop anyway 1988GTU(bit cold outside for working on anything).
ifixalot: there were six quarts that went into the trans. As for checking, it was full before the fluid/filter change. With only drops on the pan and a small wet spot on the driveway it can't be too far off. I can't check the trans temp, would be nice if I could.

[3X00-Modified]

Is dexron VI or aka 6 not 4, that would be IV

[Money pit Beretta]

Got it! Dyslex IV or Dex VI.

[ifixalot]

I had recently been working on my mini van's valve body. After installing a valve body kit, changing filter and fluid etc.,
I took it for a drive. While in drive, I felt a slight clunk.
I thought WTF is that? I got home and checked the fluid. It was low. I guess I lost more than I thought.
I added some and the clunk went away.
So since you said you had a leak and just changed the pan gasket etc. It seemed logical to me
that perhaps, like me, you didn't check the fluid level before driving the car.

[3X00-Modified]

6 quarts with only a pan drop should definitely fill a 4t60e unless he let it drain overnight.

[Money pit Beretta]

Well that is a good tip, thanks. It only drained for about 30min it was cold though(sat overnight). Drove it to work the day before. Burned my hands pretty good once and don't want to do that again. A little warm is ok, but I did not have the time that day.