Dakota Durango Forum banner

Feels like missing in reverse

3K views 10 replies 4 participants last post by  nicemac 
#1 ·
I have a 2001 Dakota with a 3.9L with 165k miles. I just had the transmission rebuilt this week (complete overhaul including replace torque converter). I get it back and it is vibrating badly in reverse.

In park, in drive and anytime you are moving, it is FINE. Put it in reverse and the RPMS drop to 450-500 and it feels just like the engine is misfiring. The transmission man says it is engine misfire.
Why isn't it misfiring ANY other time?
The engine doesn't know it is in reverse, it only knows a load is on the engine. And if I put it in Drive, it does not shake at all. Smooth as butter and idles at 700-ish RPM.
It was not doing this before trans overhaul.
I put new Champion plugs in it just to satisfy transmission man. I sprayed the plug wires with water (actually I soaked them down for several minutes) with no arcing.
What could be going on?
Can this thing be misfiring JUST IN REVERSE?
Could something in the transmission be causing vibration that is being mis-interpreted as misfire only in reverse?
I do not believe the engine is misfiring-it is simply too smooth all of the rest of the time…
Help!
 
See less See more
#3 · (Edited)
It quit shifting when it got warmed up (after 20-25 miles of driving). The trans guy said it was burnt badly inside. He said he "replaced everything." Obviously that is an overstatement, but still, it was a complete overhaul, including converter and all electronics.

I checked codes last night - P0300, P0301, P0303, P0305.

There were no codes in it before the trans work. When the shift issue started, we checked for codes. None. Now the random misfire and bank 1 codes…

I am going to look when I get home tonight, but I am now wondering if they have possibly knocked a vacuum hose off somewhere, causing bank 1misfires.
 
#5 ·
I found the hose going from the vent on the right valve cover to the throttle body was severely cracked. More like gaping… Anyway, I wrapped it with electrical tape to close it up (temporarily) and the misfire seemed to immediately go away.

If the engine was getting unmetered air, it should have just caused a somewhat lean condition, right?

How could that hose cause a misfire only on bank 1, and only in reverse?
 
#8 ·
Cross Post from Dodge Talk.

The hose did not fix the misfire in Reverse…


I now this sounds crazy, but my 2001 Dakota engine is running rough, but only in reverse.

Background:
In December, my son called to say the transmission temperature light came on while driving home. He was only a mile away, so I told him to drive on. He made it home without any problems. I got home a couple of hours later and checked the fluid. It did not smell burned. I took it for a drive. After 20 miles of so without incident, I figured it was some kind of fluke and started home. At about 27 miles the light came back on and it started shifting erratically (would not shift at the proper shift points) I was only a mile or so from home, so I drove it back. Long story short, a local repair shop replaced the Governor pressure solenoid and sensor and told me it was OK. It wasn't. After 50 miles or so, I was right back where I started.

Took it to a transmission shop. Complete overhaul. I got it back and it drove fine, shifted great and no transmission temperature light. But it felt like it was running rough in reverse. After about 75 miles, the check engine light came on.

I took it back to the transmission shop. They said yeah, we noticed it running rough. We think you need spark plugs and wires. My response "Why isn't it running rough in park or in Drive?" "And why was the check engine light not on when you got it, but now it is?" They insisted they had nothing to do with it… Pulled codes: P0301, P0303, P0305–misfiring on the left bank.

OK. I put plugs (Champion OEM), and plug wires on it. Same problem. I put a new distributor cap and rotor. Same problem. I ran a bottle of SeaFoam through it. I checked for vacuum leaks, I have gone over it and find no mechanical problems with the truck.

If you start the truck and idle in Park, it is smooth as butter. If you put in it Drive and sit still, it is smooth as butter. When driving down the road, it is smooth as butter. Stop, put it in reverse and it runs rough. It is not vibration, it is running rough, misfiring. Stand behind it when in reverse and you can hear the misfires in the exhaust.

I spent 12 years as a Ford master technician. I specialized in drivability from EEC III to OBD II. I have a good grasp on engine misfiring and this engine is misfiring. It seems to be lean at idle IN REVERSE ONLY.

Doe anyone know if the processor purges the canister in reverse? I have checked for vacuum leaks, but they SHOULD leak regardless of which gear the truck is in. The engine mounts are not bad and I see no real movement that would be causing something move around and cause a leak only in reverse.

The only thing I can come up with is this; there is a stud on the firewall that looks like something USED to be mounted on it, but nothing is there now. I can't say for sure something was there before the transmission work, but the threads look cleaner than the surrounding area. My hypothesis is that the transmission shop could have buggered something up while R&R'ing the transmission and just removed it… Dunno. A picture of the stud can be seen here:



Is something supposed to be mounted there?

Any other ideas?

Help!
 
#9 ·
I would start by looking for possibly pinched wires between the bellhousing and the block. Maybe there is a short with the gear indicator on the transmission. The sensors in the transmission share a ground with the O2 sensors. Take a good look all around, underneath for any loose or pinched wires. It has to be something related to the tranny removal install.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top