This weekend I changed my transmission filters (and filter seal), partly for scheduled maintenance, and partly to address the drain back issue. I worked my way up to 10qts of fluid back in the transmission, starting with 5qts per the service manual. I did this by adding fluid, driving around the block, adding more, etc. I don't know how much fluid originally came out of the transmission because I spilled so much.

I now have a hard shift from 2-3. Like others who have had this issue described, it feels like you've tapped the brakes during the shift. It had never done this before my filter change.


I understand that the transmission software learns as you drive. Will it automatically learn a smooth shift? Is there a trick/method I need to follow to have it learn from scratch? (such as just unplugging the battery)

I'm also worried about the fluid level. The FSM features a nice Fluid Fill Level vs Temperature graph, but I have no way of knowing the transmission temperature. Right now it is just below the first "HOT" hole on the dipstick after a 30 mile interstate run in 60*F weather. The FSM states that the fluid should be at the second "HOT" hole at 180*F fluid temperature. What scenario will make me hit the 180* mark? I could just add fluid until I hit the second hole, but the FSM also states that overfilling the transmission is just as bad as under filling due to fluid cavitation.

BTW, has anyone noticed that the Mopar fluid is almost purple?

Add more fluid.

Check the trans fluid level when everything is cold.
Is the level at the "full hot" mark?
If not, add fluid until its just above the full hot mark.
These transmissions work better when they are over filled.

Also, which brand filters did you use? Mopar, Napa, fram, or other?

_________________
U.S. Army Retired

Mopar Filters. 2015 date stamps. Mopar and Advance Auto ATF +4

The harsh shift reported by others seems to be caused by the clutch volume index railing, the thing is the adaptation is very slow so it takes some time to get there. This is usually characterized by a quick learn fixing the shift and then it deteriorates over a period of days to weeks. In your case, if it appeared suddenly, something has changed to cause it. The control loop may adapt itself over time resulting in the shift returning to normal. Unplugging the TCM doesn't achieve anything but you can expedite the process by having the dealer or equipped shop to run a quick learn on the TCM.

You did remove the old seal? Did you fully seat the new seal into the transmission before installing the filter? It takes some force to seat it properly and it's critical it's properly installed or else you can end up sucking in air with the fluid.

BTW, a filter change doesn't always fix the drain back problem.

_________________
Share your ideas freely at https://www.facebook.com/groups/libertydiesels/

I used a pair of dikes to remove the old seal. I did seat the new seal flange against the pump using a small block of wood and a mallet. I had no trouble installing either filter.

The shifting issue wasn't immediate in the sense that ever since I changed the filters it has done this. I'd say it developed over the course of 30-60 miles since the filter change.

Oh, and the pan looked fine. There was a normal amount of metal dusting on the magnet and pan.

Welcome to the club. I'm replacing my tranny this weekend due to this issue. I've chased my tail trying to solve this since 2012. I hope you find a simple solution.

I know of 2 other members here with the same issue and their solution was to replace the tranny. I am following in their foot steps.

_________________
SOLD - 2006 Jeep Liberty CRD Limited
Gen2 Fuel Head - Magnaflow Exhaust - Ram transmission swap - In-Tank Lift Pump
Moab Wheels - 245/75/R16 LR E Cooper Discoverer AT3 Tires - OME Lift 790/90009 948/60069 - Etecno Glow Plugs - V6 Airbox
Pic of my Jeep!

Just wanted to chime back in and say that I had the dealer perform a quick learn on the TCM 1,000 miles ago and it has been fine ever since. I live in Atlanta so it sees plenty of 2-3 shifts. I also towed a box trailer last weekend and didn't see any issues.

I'm not sure why replacing the filters did this. Maybe the new filters changed the flow rate of the pump? Or the new fluid has different properties.