ZF 8 speed rpm goes up and down until warm?

1179 Views 5 Replies 5 Participants Last post by  Bennyb4200
Ever since I've bought the truck over 25k miles ago, my 2014 Ram 1500 rpm varies up and down until warm while in low rpm. As soon as the trans is warm it drives normal and have no issues. Never gets any worse but some days it really pisses me off. It seems like a tuning issue. Any info? I'd pay to have it disabled. I've tried to research this issue multiple times but have never seen anybody ask the same question. Don't believe it to be the torque converter because it seems like if it were bad, it wouldn't go away when warm. 140k miles on it currently. Again, has done it since I've bought it and never got worse or better.
1 - 6 of 6 Posts
Possible a idle air control problem.
Its just weird. So until it warms up I run it in 6th or 7th so I dont have to listen to it because I have the carven exhaust. It makes my blood boil listening to it when I'm already in a bad mood lol
1) Check and test the coolant and level.
2) Monitor the coolant temperature from cold to hot (it will climb from ambient to operating temperature).
3) Monitor the transmission temperature, it too will climb.
4) Access any recorded faults with the entire network and post them so the readers can view them.
Idle air control is via throttle body angle (gasoline engine).
If it is a gasoline engine, the throttle body voltage and or degree of throttle angle can also be monitored.
Simple OBD II scan equipment can offer "good enough" data to monitor those values.
One last point, does that Ram have a thermostat? Has it been tuned?
If it has been tuned, revert to the original tune and test again.
Maybe you should check the Transmission Cooler Bypass Valve
I have a 2014 ram that does the same thing put new torque converter in change megatronic sleeve o-rings I think that's what it was. An a tune up that was the first thing I did and now it's getting so bad I can't even handle driving it the truck actually jerks on the RPM bounce and it doesn't go away no more once it warms up motor. And some days it seems like it's could be the motor but then it could be the tranny just so hard to pinpoint what one's doing it
1 - 6 of 6 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.