Engine/Transmission (1998.5 - 2002) new apps and trans....still screwed!!

[TFarrell]

here is a question i was wondering if any of you guys could answer. i have a 98 2500 auto. i just put the timbo apps on and had the trans rebuilt about a month ago. my question is now all of the sudden i was having problems with the torque converter going in and out of lock. the trans guy says this is becasue the apps signal voltage is moving around alot as read by his snapon computer. but if you take a meter to the signal wire at the apps it holds a steady voltage. so im guessing somewhere between the apps and ecm the signal is getting noisy. does this sound right? also the other day i disconnected the batterys and reconnected them to reset the ecm and now it locks great. i stopped by the trans shop so he could plug it in again and he says the voltage is still jumping around even though for now everything is working fine. what do you guys think?

 

[jtwcummins]

Noise on the APPS line is pretty common. Most DVMs don't sample fast enough to show the fluctuations, a scope or scanner will. DTT sells a noise filter kit to eliminate the problem. Had on my 97 when they did the trans. Can reroute the wire to help but the filter is the way to go. Also, it's time to check the system grounds. Had bad corrosion on the grounds by the batts on the fenders. Fixing stopped other wierd problems.

 

[TFarrell]

so a noise filter such as the dtt or navarone should stop the voltage fluctuation?

 

[fox]

If your battery connections are loose/dirty, nothing will help. I found the right battery ground loose at the block and that and the DTT filter cured it.

 

[TFarrell]

ok i found the culprit of my constant lock/unlock problem. aside from checking and cleaning all the grounds and the battery terminals which really didnt help, i was checking out the alternator (electrical noise maker) and it looked like it was soaked in oil/antifreeze. i then remebered the provious owner saying the truck over heated at one point. the truck doesnt leak anything now so im not exactly sure where the sludge all over the alternator came from. i figured i would take a shot in the dark and purchase a rebuilt alternator from pepboys to see if this would finally fix the constant lock/unlock. well to my surprise it did! couple thousand miles later no problems at all. just figured i would share this incase someone else was having a similar problem. -tim