well guys I got some good news and bad news. the good news is I got lockup to work by staking the isolator valve in the full open position, even though there was a tube in there blocking it there was still enough movement that it wouldn't lockup.


the bad news is it will come out of lockup on the highway after about a half mile when fully warmed. when lockup slips out I can push the gas some more and it will lock again. I can do this maby 3 times then nothing.


but since I staked that valve it now lets me control lockup manually. but only after the computer has set max line pressure when it fully warms and after computer kills lockup. then I have hard 1-2 2-3 shifts.


so basically I only have manual lockup control when the computer sets max line pressure and denies lockup.


any ideas?

 

still trying to figure this out. getting colder out. any ideas as to whats wrong.

 

correction. I have manual lockup control at any speed when cold. when warm I have no manual control but if I push the gas harder it locks up no problem for a second then nothing after I let off the gas a bit. but when the computer commands high line pressure I will have manual lockup all the time in any condition even it its 100f outside. so as long as I have my foot down on the gas when its warmed up and no high line pressure it will stay locked up by about a 30 seconds pass and I will be at about 100mph. still locked up. its weird. cause if I try to cruise at 55mph it will slowly unlock. then I push my foot down on the gas pedal a bit more and it will lockup again. but in order for it to stay locked up I will have to press harder and harder in the gas pedal for it to stay locked up. it seems like. even manual control when warm I flip the switch and nothing happens till I press the gas a bit harder then it will lock up only for a bit then come out. even at 30mph when warm I flip the switch, goes into lockup then it will slip out. with switch still on I push the gas a bit harder it will then lockup again but only for a second or maby 5 seconds then out. but as long as I keep my foot on the gas hard it will stay in lockup but I will find myself doing 50 in a 30 if I do that. also when partially warm and I flip the lockup switch it will drop maby a 100rps and if I press harder on the gas it will drop about 400rpms but will only stay there if I keep on the gas but like I said if I keep on the gas I will find myself doing 80mph in a 55mph pretty quick. the 100mph was a exaggeration.
please if anybody has any info on this please let me know. my mechanic I sent this too to have it rebuilt is getting very frustrated and would like to figure it out on my own but will take it back to him if I have too

 

I have installed a big transmission oil cooler inline with the stock one. and now I have lockup a bit longer than I normally would. without oil cooler im lucky to get about half a mile in lockup before it slips out at 55mph. with the cooler I can go about a few miles at 55mph then slowly slip out. but computer never goes into high line pressure. weird. ive only tested it a few 5mile runs out of town.


any thoughts.. seems like im talking to myself at this point...


to me it sounds like a loss of line pressure in the tcc apply circuit. because when oil is cold I have lockup and when its warm I don't. when warm oil becomes more thinner and is able to escape easier. and when I put it on manual override and hit the gas it will lockup no problem till I let off the gas a bit. same goes if computer is controlling it.


so by manual control working I have ruled out any computer or engine problems. and it has to be in the trans right?

 

today was about 50f outside. pretty chilly. went on a 12 mile drive to the next town and it stayed in lockup the whole way there. WOW never did that before. but on my way back after about 30min or so cool down I got about a mile out of town then it slips out of lockup. push pedal a bit harder it goes back in then slowly out. manual control same thing.


on the way there the truck was stone cold and computer was controlling lockup all the way there. it may have slipped out once but it came back. on the way back it was still pretty hot and a mile out of town no lockup at all. but like a said hit the gas a bit harder and bam lockup but only for a few seconds. only when hot.


gotta be a trans oil pressure issue? right?

 

 

well I took it back to the shop and the mechanic replaced the tcc apply valve seal with a Teflon seal in the pump body.


now I don't have lockup at all now. well maby a 100 rpm drop then nothing. and almost instant high line pressure when I hit 45mph.


now when I hit the switch in high line pressure mode it barley does anything. even if I hit the gas a bit harder it wont lockup for that few seconds it did before. just keeps reving up but with a bit of resistance. before when in high line pressure mode I can flip the switch and bam lockup but not anymore.


what a nightmare this has been.


any info? thanks