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I have a 98 Chevy C3500 crew cab with a custom built HT383 Vortec and built 4L80E. I use this truck as a tow vehicle for a fifth wheel camper and daily driver. I have about 1000 miles on this combo and it has worked great until two weeks ago, the TCC will engage when you first take off then after a mile or so will kickout. Once it kicks out it will not engage again until the key is turned off or you go thru the code clearing process on a scanner, it does not set a code. While using the scanner you can engage it and it will stay in. We have replaced the TCC solenoid and internal wiring harness, and also the brake light switch. When the trans was built every thing in the valve body was installed new.  ANY help would be great!  

to start with...   print this chart..

write your scan tool values down on the proper line.. then when done you can compare them to what is on the chart..

almost all scan tools have the ability to record a section of live data stream... either when the check engine light turns on or a  manual trigger by you or a passenger when the problem happens.. so we can see what the sensor data is when it kicks out of TCC..   you can hook most scan tools to a PC also.. so you can download the recorded data ..

 

one more thing...     NOT all scanner will display all the actual codes that are set...

code readers may not display them above P1000...

post the brand and model scan tool you have... and which software cartridge or version you have... i will look up the info and make sure that its works..

there are inexpensive scan tools like the harbor freight 98614...   they are lacking when compared to a true professional unit..  but for basic OBD2 stuff.. they are the best for the buck..  

Did you replace the manifold pressure sensor on the valve body? That could be the problem.  

hello I am doing an 80 now so I will check when I get to the valve body... Now on to figure this bird out and check some things...

You said a custom eng? what was changed? the ecm or computer has built in strategic and by what your saying something is going on that the ecm does not like when the TCC is applied... So first I would try and see if it's mechanical or computer problem sensor ect.

More about me I been in the dealer as the head tranny man and driviablity and eng repair rebuilding to ending up at a tranny shop and I been doing computer controlled trans for years and this does work infact we were advanced members of transgo's tech team and its from them years ago

Ok here it goes... ecm's that control how the trans should work after so many years miles so after rebuild some strange shift complaints that would not go away unless we "Dead Headed The ECM" take the pos. neg. cables off wait a min or so and for I forgot the exact time but you then use a alligator test lead and connect them for so long - both cables together and that discharges the capacitors and starts them over

and again this has fixed a good hand full over the years...