I recently, within last 2 weeks, started to have what feels like a “jerk” when my automatic Durango shifts. The “jerk” occurs when the car is cold (sporadic) and after the car is hot. When the car is hot it’s a lot more noticeable and frequent. The durango has over 120K miles and the last transmission fluid flush it had, and the only one done, was about 99K. I took it to my mechanic, he didn’t do the transmission flush, and after a whole day of tests and diagnostics he says that the car has all the right timings and the only thing he could recommend is a transmission flush. He thinks the viscosity or correct viscosity could be causing this. My mechanic is fair and one of the better ones I’ve dealt with. In fact me didn’t charge me at all for the work done. I just want to see if this made sense to you guys and hear any other causes or recommendations. Thanks
Is this mechanic a specialist in transmissions? Transmission work is a specialty within auto repair and, especially these days, requires people who are pretty much full time & fully trained transmission techs.
So if I were you I might take it to my best local transmission shop for a look & second opinion.
Your real problem here is that you went 100K without servicing your transmission. When it was “flushed” at 99K was the pan dropped and the filter changed? If you do have your mechanic do anything, you don’t want it on a machine - you want a human being to drop the pan, inspect its contents and change the filter. What goes back in the transmission must be ATF +4 - it can’t be anything else and it can’t be something + an additive that someone claims converts it to ATF+4. My own preference would be to have a transmission specialist inspecting my pan.
Then I will kook for a transmission specialist. The problem is getting more noticeable and I depend on my car, as we all do, a lot.
Thanks for the quick response and information.
PSS - Would the dealer be considered a transmission specialist or would it be a independent shop? What credentials, if any, could I ask for?
I think that dealers are hit and miss. My own impression is that dealer shops often have someone who has been trained to operate a scanner, follow a flow chart in a diagnostic manual and then say “you need a new transmission…” Meanwhile they probably know little about transmissions transmissions themselves.
My own preference would be an independent transmission shop - it must not be any national chain-type of transmission shop. You want the kind of place where the guy who looks at it is the same guy whose name is on the sign out front.
Dont let your mechanic do a flush on this. Do though have a trans shop look it over and do some diagnostics on it.
Ok So here goes the details of my “Transmission Repair” quest. I will right of the bat take blame for not asking my mechanic who he would recommend as a transmission mechanic but I will not take the blame for him not saying you should have a transmission mechanic look at this. On Tuesday morning, I took my car to a chain transmission repair shop. When I was driving off the lot with a mechanic who would drop me off and then come back the “symptom” occurred and before I could say something he said you have a “slip”. I don’t know what that means but I was just happy someone had finally felt the issue. I was told at this shop that there would be no removal of parts without my consent and that the diagnosis they would do would just serve to help narrow the problem. Made sense to me. When I returned 4 hours later I was told 1) the found 2 codes in the computer that indicated problems with the transmission (I don’t know what those were), 2) that the pan has a magnet in the center to trap pieces that fall and that an acceptable level of droppings would be less than a quarter and I had an inch, 3) that if I continue driving I will loose 3, 4 gears and reverse and that I would only drive as fast a my second gear would allow. The cost would be between 1,000-1,500 but can guarantee as he doesn’t know what he will find. He said that since the mechanic has not fully put my car together and the liquids where cool we could start immediately. Luckily the mechanic has put all the bolts back and I asked for my keys and got out of there.
I have so many question on this but will hold off in order to continue.
I took the car to my mechanic and told him the story. He put the computer to the car and sure enough he saw the codes but couldn’t understand why the check engine never came on. He’s son, which is a mechanic there, took the car for a drive but could not feel the issue. They recommended me to the transmission specialist they use.
After a whole day at the transmission specialist, this was yesterday, he told me he couldn’t find anything wrong. Yes, he saw the 2 codes, he reset the computer and told me that in a transmission it could be either mechanical, hydraulic or electrical or any combination of these that can go bad. He said he doesn’t think it’s mechanical and that everything seems to be working to manufacturer specs. So my questions are
- what is a slip?
- do transmissions pans have a magnet
- how do you get to see the magnet and the trapped shavings without removing the pan
- should I do a transmission fluid change just because the first shop dropped the pan to look at the shavings and stored by transmission fluid temporarily somewhere? and
- What the heck is wrong with my car?
1)the link between an engine and transmission works basically by mushing together spinning disks (clutch/clutches). They are supposed to slip for a bit first before they both spin together. That way you don’t get whiplash and break your driveshafts & stuff when you first start out and change gears. When the clutch (manual) or clutches (automatic) get worn your engine can rev way up without the power really making it to the wheels - there’s not enough “friction material” left for the disk(s) to get their full grip (though is can also come from fluid pressure problems). That would be called slip. Slipping is not hard shifting - but slipping can lead to hard shifting if the computer “sees” the slipping and ramps up the fluid pressures to reduce the slip.
yes, automatic transmission pans have magnets.
you can’t inspect the magnet without removing the pan.
Are you kidding me? This place dropped your pan and then did what? Did they clean the pan & magnet? Did they replace the filter? They put your old fluid back in? If all of that happened as you implied then I’d call it malpractice.
How the heck we we supposed to know. You didn’t even report the dumb error codes. However, if you had an inch (!) of sludge in the bottom of the pan then just give in now. You either dump the car or figure out how you want to deal with having the transmission fixed.
I hate to say it but you need to find a whole different transmission shop. I have no idea what the national chain place did, but I already noted above to stay away from those kinds of places. Then this other character - who pulls error codes but then says he can’t find a problem? Ok, there are intermittent issues, so is it just that he couldn’t get the transmission to behave poorly so couldn’t diagnose? The codes that were pulled have to give him more than “electrical, hydraulic, or mechanical” - well I could have said that without knowing anything at all. I could probably make some guesses/suggestions based on the codes - but then I don’t know what they are, do I?
I thank you for the information, suggestions, comments and the input you have provided. When I posted this last reply it was in no way shape or form towards you. I just wanted to post it on the forum and get feedback. With regards to 4) I can only guess that they put the same fluid back. As there was no charge. I prey it was not tainted while in another container. I don’t know if they cleaned the magnet but I will definitely have it checked when I get my transmission fluid changed asap. The last transmission mechanic I spoke with is currently at lunch but will get the codes after and I will forward. He wants to take my car home, 100 mile round trip, to see if he can get the symptom on that drive.
What I can’t understand is that I notice the issue after I drive at 60-65mph for about 30 minutes and I do some errands. Every time I start the car, do some driving, braking and stopping after the 30 minute drive the “jerk” at 3rd gear gets worse. I have mentioned this to all mechanics that I’ve taken my car to. The mechanics here close at 5PM and don’t work weekends so this makes it kind of difficult but I will try to leave early and take it to them.
Is there nationwide database with mechanics that you might refer me to? I live in the Houston, TX area.
Once again, thanks for your help.
The Error codes P1684 , P0734 , P0935.
The P1684 just means that your PCM (computer) lost power recently (within the last 50 starts). Presumably that’s b/c the battery has been disconnected, either by you or one of that shops that looked at it. If that’s not true then you do want to think about tracking down a power issue.
The other codes will have to await a transmission specialist (which I am not) - but every time I reply it gets bumped and the board’s resident expert (transman) may happen across it.
What little I know is that P0734 is an incorrect gear 4th gear ratio. There are probably 2 speed sensors on the trans. One will measure the input speed (engine side) and the other the output speed (to the drive shafts) and if the computer doesn’t see the correct relative speeds given the gear it is in it will set this code. Unfortunately I’m pretty sure that if this is only a 4th gear problem then it won’t be as simple as a speed sensor. In fact, its likely to be slipping - its probably what used to be the 4th clutches lining the bottom of your pan.
The P0935 is a problem in a line pressure sensor circuit. Automatics basically run by pumping the trans fluid around and the fluid has to run at the correct pressures for everything to work right. The only ray of hope I could offer would be that this could just be a sensor or wiring problem and if the computer can’t get the line pressures right then this could create slipping. Of course if its been going on a long time then it probably still just means that your friction material is in the bottom of the pan and your fluid is probably burned up.
The hard shifting is probably happening b/c when the computer detects one of these problems it is ramping up the line pressure as a way to actually minimize damage.
That’s all I’ve got - and it mostly stretches what I know. But as I said, my bumping it might get you better info from people who know better. My own gut feeling is that your transmission is toast.
WOW that last statement is NOT good. I’m confuzed when you say that the transmission might be toast. It hasn’t had the problem since I left the chain transmission shop. It seems to be moving correctly and no sounds or burnt smell. I’m hoping that your contact will shed more light on this issue.
To be on the safe side, I would like to change the transmission fluid and filter as Im not comfortable with what the chain transmission shop did. I would also like to see if the erased transmission codes returned after the second transmission mechanic erased them.
Im prarying this is just a computer gone temporarily crazy issue and the reset took care of it. On the change that the transmission is toast does that mean that it can be fixed (severity determined upon taking it apart) or do I need to purchase a new transmission?