88 d-100 computer Question

[moparker]

Is there any way to tell by the fender tag if a truck came with a lock up converter option?

 

[sicksatellite]

should be able to call a dodge dealership with the vin, and they'll be able to tell you

 

[racedodge]

if it is a 904/999 you can pretty much guarantee its a lockup converter.. if it is a 727.. you will need to provide me the PK numbers on the trans pan rail, drivers side.

i have an 88 d100 318/904 trans that has the lockup converter.

 

[moparker]

My truck has it but, mine won't read bera metric pressure so it won't run when it is cold out. I replaced the computer and that fixed it but, it doesn't have the brains for the trans lock up. I'll post the numbers later.

 

[racedodge]

My truck has it but, mine won't read bera metric pressure so it won't run when it is cold out. I replaced the computer and that fixed it but, it doesn't have the brains for the trans lock up. I'll post the numbers later.

your lock up is controlled through hydraulic pressure, not from the computer. if you are not getting the lock up function, it is due to an internal transmission issue where the appropriate amount of pressure is not being built up to activate the lock up function. the lockup function is fed transmission fluid in the VB through a bypass tube. if the valve body has restrictions of flow.. it will cause a lock up function, a shifting function, or a throttle pressure function to not work properly.

i think i may have confused the situation more or less, not sure as I am still wondering why you said something about barometric pressure?

 

[moparker]

The truck wouldn't run when it was cold out. The wrench at the garage read the what the scanner said page by page and that was one of the things that he noticed wasn't giving a reading. The lock up worked with the other computer but not with the replacement.

 

[racedodge]

The truck wouldn't run when it was cold out. The wrench at the garage read the what the scanner said page by page and that was one of the things that he noticed wasn't giving a reading. The lock up worked with the other computer but not with the replacement.

the lock up is in no way connected to your computer at all. the lock up converter is a hydraulically actuated device that is separate from your computer altogether. in the later model OD transmissions (46/47/48RE's) the lock up was controlled by the computer, but in a 1988 truck.. it is not

 

[moparker]

Well, any idea why it worked with some computers ane not all?

 

[racedodge]

how do you know it is not working? what are you experiencing that makes you believe that the converter is not lock'n up at or around 40-45mph? when the lockup transitions, it usually is a smooth transition and will lower your rpm's about 300-400 rpms. do you have a tachometer that you are viewing around 45? Mine locks up at 45 mph at a mild throttle pressure (i.e. accelerating calmly).

 

[moparker]

I don't have a tach but I can feel when it would shift. It's not shifting and the rpms stay up. Mine would shift at 45 as well. I hope we can figure this **** out.

 

[moparker]

With the other computer I could go out in the morning when It is cold out and it would buck kick like it is misfiring. Come home after work when it has warmed up and it is fine. Changed the computer and it was fine.

 

[moparker]

I looked it up in my shop mamual and the tranny is controled by fluid pressure and the electronics. Went to pull a part and got another computer and all is well. Thanks for the help everyone.