Another Hard Shifting ZF8 1500

[jjjefferson]

2015 Ram Big Horn
5.7 Hemi
ZF8 Trans


At about 45K miles I noticed a hard upshift from 3rd to 4th and it coincided with the onset of cooler weather. It got to a point where I isolated the exact conditions for the hard shift:

1: Let vehicle sit for 90 minutes.
2: Find a slight incline.
3: Accelerate up slight incline to 30mph.

It will hang in 3rd gear....then act like it disengages, flashes the ECO mode light...slams into 4th...flashes eco light again....then all is well. It does this EVERY time its been sitting longer than an hour.
After a couple of months of dealing with it...I took it to the Dealership. Give them the exact parameters and the description. Of course, they cant find anything wrong and no codes. When I pull out of the dealership on a cold November day in 2018. Bam! .....hard shift. I debated taking it back...then remembered....no code...no issue.

TODAY: Cold start....pulled out into traffic.....up slight incline and at 30 MPH...not only did it hard shift....it slammed into 4th three (3) (III) TIMES! This time...that beautiful BING! followed by the "CEM" Light. Drove straight to the dealership.

Explained the issue again. Pointed to the CEM. AND showed them 3 videos on my phone showing the hard shift. Had a 20 minute conversation with the Chief Mechanic thoroughly explaining the situation and showing him the videos. I explained its "time" based not "temperature" based. He raised and eyebrow at that one. It happens stone cold...and it happens after a lunch stop. They now have the truck.

The code was for a 3rd gear bad shift. So....at least I have proof this time.

And the waiting begins.

JJ

 

[RamCares]

Hi @jjjefferson,

We're sorry to hear that you have ongoing transmission concerns with your Ram. Please send us a message if you're in need of additional assistance while your truck is in service.

Darlene
Ram Social Care Specialist

 

[jjjefferson]

Well they must have found something....they had to hold the truck so their "Transmission Specialist" could look at it.

No news beyond that. Won't know anything until monday.

 

[Burla]

New tranny time, nice. Ask them to make sure pretty please with sugar on top to put a new rear main seal when they drop the tranny. It is a twenty dollar part usually, and if not replaced can lead to a leak. Tell them you will bring them one, or pay for it if you have too. Legally they might not have to replace it, but it is worth the twenty bucks.

 

[cancunlsp]

My curiosity is peaked with this. Mine does the same thing but not every time.

 

[crazykid1994]

I had an issue while cruising back from Georgia. My truck would slam into 3rd gear downshifting. It has t done it since. I’m thinking it was from the cold weather. I could feel it slip a little then slam. Did it on 3 different occasions. I have since been unable to duplicate this

 

[jjjefferson]

Well.....they are replacing the "Valve Body." Apparently it is on "backorder" and they have no idea when it will come in.

One week down....how many more to go? I've watched a few Youtubes on the valve body rebuilds. It doesn't look that complicated....you just have to take out about 20+ screws to get inside the thing.

I'm using my winter beast as my daily commuter in the mean time. a 2000 Dodge Durango with 174K on her....and of course....she's now dripping antifreeze. LOL. When it rains...it pours.....I will be replacing the hoses and waterpump on her over the weekend. I do miss my 1500 :-(

 

[Burla]

You have a flu, and they are giving you a cough drop, I hope that settles it but I fear it will come back. Maybe it was a line pressure thing, but I bet it is an issue within the clutch pack. You shell out good dough and depend on a warranty, they should have just swapped it, they could use the core for the next guy and so on.

 

[PoMansRam]

^ That's my thoughts on this too and I hope we're wrong!

I have heard some of my friends and co-workers with Hemi/8hp70 Rams complain of hard shifts on takeoff after cold starts, but no issues after that. None of them would ever think about a transmission other than that. Change fluid? What's that? LOL

My pentastar/8hp45 seems smooth all the time. I've used it a bunch of times after a 0degF start the last week or so, but I'm only at 29K miles.

 

[jjjefferson]

PoMan,

Stay warm up there heh heh heh. I'm originally from Chautauqua County. Temps didn't have any impact at all actually it would do it hot or cold. Just let it sit for an hour or so....and it would hard shift again. Almost like a leaking back-check valve that would let the fluid drain.

JJ

 

[jjjefferson]

Update:

So they swapped the valve body (and computer) and called me to pick it up last Thursday. I got in.....pulled out of the Dealership...and WHAM....hard shift 3rd to 4th. Turned around and went back in. An hour later "Chrysler Corporate" had a plan. "Its still in learning mode" they said "drive it a couple of hundred miles and get back to us in a week or two and let us know how its going." I laughed.....I can put a couple of hundred miles on the truck commuting to work ....in two days. They also said "DON'T BABY IT!" Ok...I hear you loud and clear....balls to the walls and destroy the thing. So I took the truck home. It slammed again. Took it to work....it slammed again. Took it to lunch...it really slammed. Then back from lunch....no slam. Hmmmmm. Back home.....no slam. Perhaps.....maybe....possibly....the morning would tell. Took it into work the next day.....no hard shift. Huh....who'd a thunk it.

Then I went to lunch....... ooohhhh myyyy.

With my "GO-Pro" rolling.....it got up to 30 mph major shift slip and a shuddering slam. Pulled up to the next stop light. Again....30MPH and the tach rev'ed to 3300 RPMS before dropping the hammer on 4th gear. I had a co-worker in the truck who knew the story....he was wide eyed. Then...at the next turn....as we sped up to 25mph..... BING! CEL light pops on! Winner Winner Chicken Dinner!!! (No...I really said that on the video ). And the truck was "stuck" in 3rd gear. It would neither up-shift nor down-shift. I had to pull over.....put it park. Shut it off for a minute. Then started it back up....still had the CEL....but it would at least shift gears.

I drove straight to the dealership...do not pass go....do not collect $200. Showed them the video in full 1080P and left the truck. Service Manager believes they will be told to "replace the unit" which I interpret as a new transmission. We will see.....I am back in my coolant leaking 19 year old Durango.

JJ

 

[autumnwalker]

Interesting ... I'm having hard shifts in mine too. I've been into the dealer twice. First time they told me it was a TSB reflash, it made no difference. 2nd time they told me there's nothing wrong.

Suggestion was to drive it straight to them when it does it again, don't shut the truck off, etc. Dealer is a good 20 minutes in the wrong direction from my place of work and home. The rough shift happens every single day on my commute to / from the office. Great solution dealer, great solution.

 

[Burla]

go back and see my first post, make sure they put a new rear main seal. don't just trust they will. even if you have to pay for it.