I've been lurking this forum since I bought the truck and am always amazed at the amount of extremely useful information posted here.
I hope that maybe I can contribute something now.
I noticed that the transmission was running hot after an hour or so at 70+ MPH. It would be stable around 190 degrees F before that.
After the temp started to rise it would continue until I slowed down. It would be accompanied by the expected hard downshifting and whine with a hot transmission.
I took it to the dealer twice for this issue. Twice they kept it for a week and said it was fine now and they couldn't reproduce the problem (I did give them specific instructions guaranteed to cause the problem). I later found out that they didn't even try. They just drove it around town and never on a highway. Eventually they told me that I'd have to overheat (destroy) the transmission to get any work done on it, even though I bought an extended warranty with the truck.
I took a photo of the gauges while running at 255 degrees F and gave it to the dealer along with an email I received from ZF stating that "There is a cooler bypass valve in the cooler line, which could be restricted. Make sure you do not drive under those heated conditions, because the transmission is in danger of overheating".
Essentially I took a truck (under warranty) to the dealer with proof of a problem and told them what part to change. That wasn't enough. They did nothing. FCA backed up the dealer when I called them.
Enough whining. With the current quarantine situation, I started to run out of maintenance items to take care of on our vehicles.
I really didn't want to touch the transmission on the truck as it was under warranty, but the dealer basically told me that the warranty was worthless so I decided to do it.
You need to be able to trust your vehicle on long trips.
I bought the pan/filter (Mopar 68225344AA), 7 litres of ZF Lifeguard 8 fluid, a replacement Transmission Heater (Mopar 68463479AA) and a Transmission Line Disconnect tool (Mopar 9546).
The heater took a few hours to do, mostly due to pre and post work (remove front driveshaft, disconnect shift cable, disconnect trans cooler line and coolant line mounts...).
The hardest part was getting the coolant lines disconnected from the top of the Trans Heater. Just a tough area to reach for a fat guy under a truck.
I did not drain the coolant. Seems like a way for someone to sell more coolant. Instead I used 2 sets of pinch pliers on the rubber coolant lines in the engine compartment that lead back to the transmission. Much less mess.
I did the pan and fluid replacement the next day. That took a couple of hours. Not a big job. Make sure to torque the drain plug on the pan before installing. It's located directly over the exhaust and there's not enough clearance for my stubby Allen wrenches to get at.
Fluid came out very clean to my surprise. Didn't look terribly different from the new fluid I put back in.
When topping the fluid off I did something probably controversial. All the documentation I could find stated that the vehicle should be level when checking the fluid level.
This transmission is used in many makes and models. All have the transmission mounted at different angles front to rear. Not a big difference but big enough when comparing a BMW 7 Series and a Ram 1500, coupled with the fact that the fill plug is at the rear of the case, not in the middle where mounting angle would not be as critical.
I asked ZF whether to have the vehicle level or the transmission and the response I received was not nearly specific enough. Basically "level vehicle and don't worry about the details". Seems like a non-answer for a precision piece of equipment.
Now I've taken the vehicle on the route that previously guaranteed 255 degree F trans temps - 2 hours at 75 MPH. Stayed rock solid at 188 this time. I also noticed that it climbed to operating temperature more slowly.
Here are "Before" and "After" pics -
I hope that maybe I can contribute something now.
I noticed that the transmission was running hot after an hour or so at 70+ MPH. It would be stable around 190 degrees F before that.
After the temp started to rise it would continue until I slowed down. It would be accompanied by the expected hard downshifting and whine with a hot transmission.
I took it to the dealer twice for this issue. Twice they kept it for a week and said it was fine now and they couldn't reproduce the problem (I did give them specific instructions guaranteed to cause the problem). I later found out that they didn't even try. They just drove it around town and never on a highway. Eventually they told me that I'd have to overheat (destroy) the transmission to get any work done on it, even though I bought an extended warranty with the truck.
I took a photo of the gauges while running at 255 degrees F and gave it to the dealer along with an email I received from ZF stating that "There is a cooler bypass valve in the cooler line, which could be restricted. Make sure you do not drive under those heated conditions, because the transmission is in danger of overheating".
Essentially I took a truck (under warranty) to the dealer with proof of a problem and told them what part to change. That wasn't enough. They did nothing. FCA backed up the dealer when I called them.
Enough whining. With the current quarantine situation, I started to run out of maintenance items to take care of on our vehicles.
I really didn't want to touch the transmission on the truck as it was under warranty, but the dealer basically told me that the warranty was worthless so I decided to do it.
You need to be able to trust your vehicle on long trips.
I bought the pan/filter (Mopar 68225344AA), 7 litres of ZF Lifeguard 8 fluid, a replacement Transmission Heater (Mopar 68463479AA) and a Transmission Line Disconnect tool (Mopar 9546).
The heater took a few hours to do, mostly due to pre and post work (remove front driveshaft, disconnect shift cable, disconnect trans cooler line and coolant line mounts...).
The hardest part was getting the coolant lines disconnected from the top of the Trans Heater. Just a tough area to reach for a fat guy under a truck.
I did not drain the coolant. Seems like a way for someone to sell more coolant. Instead I used 2 sets of pinch pliers on the rubber coolant lines in the engine compartment that lead back to the transmission. Much less mess.
I did the pan and fluid replacement the next day. That took a couple of hours. Not a big job. Make sure to torque the drain plug on the pan before installing. It's located directly over the exhaust and there's not enough clearance for my stubby Allen wrenches to get at.
Fluid came out very clean to my surprise. Didn't look terribly different from the new fluid I put back in.
When topping the fluid off I did something probably controversial. All the documentation I could find stated that the vehicle should be level when checking the fluid level.
This transmission is used in many makes and models. All have the transmission mounted at different angles front to rear. Not a big difference but big enough when comparing a BMW 7 Series and a Ram 1500, coupled with the fact that the fill plug is at the rear of the case, not in the middle where mounting angle would not be as critical.
I asked ZF whether to have the vehicle level or the transmission and the response I received was not nearly specific enough. Basically "level vehicle and don't worry about the details". Seems like a non-answer for a precision piece of equipment.
Now I've taken the vehicle on the route that previously guaranteed 255 degree F trans temps - 2 hours at 75 MPH. Stayed rock solid at 188 this time. I also noticed that it climbed to operating temperature more slowly.
Here are "Before" and "After" pics -