Originally Posted by DodgeGuy85
Hey guys I have a quick question for anyone who has ever experienced this. I have a 96' 1500 5.2 magnum slt with the automatic. Yesterday on my way home from work I noticed that when I was in 5th gear with overdrive on right around 55mph and crusing at 1-1,100rpm I noticed that the rpms would jump back and forth from 1,100-1,200 rpms and wouldnt stay in one place and this was all happening with keeping my foot steady in place at 55mph only. Is this a sign of premature tranny slippage or is it normal at this speed and rpm range.At 50 mph it would'nt do and the same at 60 just only happens at 55mph. or could it be the computer not knowing if it should shift up or down? It just started doing this and is really annoying? have any of you ever had this same problem with same type of truck. I'm thinking its time for a tranny service and filter change what do yall think? thanks for any input in advance...
Well normally the OD shifts frequently, but to start lets just do basic cleaning which might rule out the very basic things which most times cause the issues. Clean your throttle body and IAC, don't push or pull the IAC pintle cause you can ruin the IAC that way.
Now that's out of the way, it sounds a little like the truck is surging but since it seems to do it on at the speed that OD activates then it would rule out plain surging, if it surges by surge I mean jumps from one rpm to the other and back, if it surges all the time then it would be a bad TPS but if it surges just at a certain speed then it's probably normal but yes have the fluid changed and filter changed and have the bands adjusted like normal. But surging at a certain speed that happens to be when the OD kicks on seems to be pretty normal except for maybe a bad PCM or faulty TPS or something, sometimes it can be the TPS because the TPS is pretty much a rheostat and it over time develops blind spots that would not make a CEL illumination.
When you put the throttle body back on, replace the gasket and torque the bolts to 200 inch lbs. When you put the IAC back on put a little motor oil on the o-ring and then torque the torx scres to 60 inch lbs.
I doubt it's the IAC because that's mostly for idle duh Idle Air Control haha, but the TPS is possible but unlikely because if it was then it would jump rpm in other speeds as well. But just so you know it is very common for the OD to do funny things, OD shifts in and out of gear alot which would cause the engine to change rpm's, this is another reason when towing you should keep OD off because you can burn out the friction plates faster because of frequent in and out shifting.
P.S. If you're ever in north east florida in flagler county send me a message and you can bring your truck over and I'll do free diagnoses and free repairs. Just bring your own fluids and parts the labor is free, of course you will kind of have to help or atleast watch and learn lol... You can always buy ATF+4 and buy a filter kit like 7 bucks at autozone and bring it to me and I can adjust the bands and change the fluid for you for free, provided you watch and learn so you can do it on your own some day hehe. But seriously, I love working on trucks that's why my labor is free pretty much, schools over and I got nothing much to do so why not fix trucks, I don't charge also because then it's considered a business and all that crap.
But yea you can just drive the truck up to me and I can do everything for ya, everything from the TB cleaning to the transmission. Just tell me what you want to do and I'll be more then happy to help.