fishy_mcfish

like the title says im having issues with my truck. the transmission doesnt seem to want to shift out of 2nd gear? almost like its stuck in 4Low. When i take off its real sluggish and kind jerks as it shifts gears then gets moving then quickly after it feels like another shift then it will move alittle better. at 25 mph the rpms are at 4000....i can get up to 40 mphs and the rpms are almost redlined and stay that way. also if i go over 40 there is like a cutout and i cant accelerate again until after the truck has dropped below 40mph.
the truck has 188,000 miles on it, engine was rebuilt a year ago and the trannsmission and transfer case where replaced when it started having this problem but it did not correct the issue. I dont have any OD light codes are check engine codes. truck also has the ADD system on it as well.

Things ive done since owning it.
1)Replaced the ecu with no change
2)found a broken vacuum line going down to the add actuator, replaced it and no difference
3) tested vacuum at the ADD actuator on both sides and all that tested out good.
4) ive looked through most of the wiring and dont see any breaks and vacuum lines look ok as fara s i can tell

I am stumped now and really could use some help. and yes i bought the truck this way

I also have the old trany and transfer case and as I was looking at the old one just now it still has all the sensors and stuff in it, one thing was missing though. I believe its the kickdown cable. That is still on the truck and it would be the only common denominator between the two trannsmissions . both are having the same exact issues. Could this be my culprit? I've also tried adjusting it at the throttle body with no change. It kind of binds up a little too.

sechott

I'd try locking the hubs and see if it's in 4x4 when it's not suppose to be. Just a thought if it could be the transfer case.

fishy_mcfish

I don't have the manual locking hubs. Its al controlled by the Automatic disconnection differential system..or ADD...

881stGenRunner

unplug the transmission computer and drive it like that. L will be 1st gear, 2 will be 2nd gear, D will be 4th.

See if you get anywhere like this.

fishy_mcfish

as far as i know the ecu for the trans is also in the main ecu housing on my truck. I know there is a manual shift test and it says to unplug the solenoid but i dont know where this connection would be?

fishy_mcfish

yesterday I reversed the vacuum lines that go from the vsv valves to the add actuator and drove it for about a mile or two like that then got out and switched them back the right way and the truck was able to get up to 50mph but the rpms where still around 5000 at cruising speeds.
I checked and rechecked the vacuum lines to the vsv and the solenoids right there and it all appears to be ok. i also tookt he orange check valve off and blew into it, air came out of the black end but i couldnt get air to come out of the orange end, this is normal right?
I also finally got a code to pop up, code 12...now this could be because the truck has always ran with a loud ticking noise but as i discovered yesterday while checking the oil the spark plug boot for the spark plug right under the distributor wasnt on the spark plug! i tried getting it back on, thats a tight area, but it doesnt seem to fit snugly onto the spark plug...almost like the boot on the wire is to long to let it seat firmly on the spark plug. none the less its on there for now and when i fired the truck back up the engine was so much quieter

fishy_mcfish

will with the help from another person on here i got the wire dissconnected for the transmission shift solenoids and test drove the truck manually shifting and still once i put it in drive i was doing 50 and rpms were between 5000-5400. so is my tranny just toast? It was swapped with original tranny due to the same problems......
are these a340h transmissions known for having this issue? i just dont see how a second transmission be bad and have the same exact problem? its possible i guess but seems unlikely to me.

fishy_mcfish

i do have a code 12...the truck did stall on me once and i did notice one of the spark plug boost wasnt on the spark plug. i dont know if the spark plug boot being off would cause the code 12 or not though?