Convertor clutch

[arrowheadracing]

I havent had much response to my dtc 39 code. Any takers. I dont have a service manual, so I can look up the wire schematic. But is there any way to check convertor lock up functioning ? Mine seems to lock up around 50-55 mph or so. Does that sound about right ? BTW 55 mph is about 2000 rpm when it locks up it drops to 1800 rpm.

Thanks
Todd

[rjschoolcraft]

That sounds about right for full power acceleration.

[arrowheadracing]

Thats under normal light acceleration. If I dont hit 55 mph, my convertor doesnt lock up. Is that normal ?

Thanks
Todd

[rjschoolcraft]

No, it should lock up at lower speeds under part throttle conditions.

[arrowheadracing]

I figured it probably should. One more thing for me to look at now.

Thanks
todd

[B Lake]

My truck is doing the same thing. Anybody know what to check first to sort this out?

[rjschoolcraft]

First thing I would do is change the fluid and filter.

[arrowheadracing]

I have 140,000 miles on it. The fluid has been changed almost every 30-40,000 miles with filter. I just made my first long trip and tow with it yesterday. Though it wasnt super long , it was its first maiden voyage. Trailer was only about 3000lbs and mileage was 1400 miles. I did notice that when I full throttle , it slips when dropping into the next gear. More so, when the covertor finally locks up. But I noticed it a little bit into the other gears as well. The truck ran for 26 hours without being shutoff. Another first for it. Water temps never went about 190. Everything ran super smooth. I am going to look at the fluid today. I am just worried that if its slipping and I change the fluid , it might slip worse.

Todd

[rjschoolcraft]

If damage has not already been done, it sounds like there is some restriction somewhere causing the slip. Have you checked codes?

[arrowheadracing]

DTC 39 code. Thats all that came up.

Todd

[rjschoolcraft]

That is for "TCC Stuck Off" and sets any time the slip is more than 65 rpm when the clutch has been commanded on. There are a lot scenarios that can result in this condition...

Burned clutch that slips even though mechanically applied.

Mechanical problem that keeps clutch from applying.

Etc.

A GM shop manual would be very helpful to you in figuring this out.

[rjwest]

There is data in the pcm to tell you what/how bad each gear is slipping, also there are
" corrections made " by the pcm to increase line pressure for worn clutches. A high numer in field will indicate how much slippage PCM detected. May want to get a " scan " by a good Trany shop.


Also, you did'nt over fill the transmission. ?