Rpm surge and down shifting over 1700 rpm

[TGVET]

WHAT NEXT ?



While cruising above 1700 RPM the engine starts to surge and shifts out of overdrive to 3rd and then 2nd gear with RPM up to 3000. I was told by the people at DTT who rebuilt the trans it was electrical issue as the 05 to 07's were plagued with electrical problems.



I was also told it could be the "throttle valve actuator" that controls the trans. I swapped out one from another 05 my local transmission shop loaned me and drove it for a day without any problem. Thinking it was the TVA, I ordered a new one and installed it. Drove 80 miles to work with no problems. Then, on the return trip it started again. WTF ??



If I don't exceed 1700/60MPH all is fine. From 1750 to 1900 the RPM surges for a few seconds and then downshifts to 3rd & 2nd and I need to s hift to neutral and coast back to 60. Even more weird is that I can cruise at 70 and above with NO problems.

 

[cerberusiam]

Have you put it back to stock to see if it is the tuner?

 

[Bob4x4]

The super chip does not go back to a real stock And I have seen the programmable choice of od off not function so who knows what else it is capable of affecting

 

[TGVET]

Before I had the trans rebuilt it was programmed for performance/tow mode one of three levels. (Stock,performance or tow). I had driven it "stacked" like that for nine months without issues. I never changed any programming until a month or so back when I was having other issues, codes P0340,0341 & 0438 which ultimately was the cam position sensor which I changed. I changed it back to stock shortly thereafter. Yesterday I programmed it back to perf. /tow mode and am going to see if it will make a difference. The people at DTT said that if it wasn't the TVA (which I changed) it would then have to be the ECM. Everyone I have talked to about this feel the ECM's going bad are very rare.



I'm wondering if it could be the speed sensor or the throttle position sensor. I don't know what else could be sending signals to the ECM and telling it to downshift.



If I'm cursing at 60 and start going down a grade picking up speed, the tach will start to flutter and surge and then want to downshift. Once I can break the 1950 RPM / 69ish MPH point without it wanting to rev up and downshift it's fine, I can go 70 plus. But I don't like to drive over 2000/70+ unless I need to pass someone.



I towed my job trailer yesterday and it was really acting up. I don't know what else to do.

 

[cerberusiam]

You have all the symptoms of an APPS problem if it is occuring at a certain pedal setting.

Is the engine actually fluttering or is it just the tach?

Have you check for codes?

Might try unplugging the fan and see if that makes any difference.

 

[TGVET]

The engine is fluttering or rather, surging with tach jumping then downshifting.



No codes, no engine service light.



Can the fan be unplugged after the engine has been running for a while and up to temp ? I am not having the problems until after I have been driving for a while at freeway speed.



What is the APPS ?



Thanks again.

 

[LNaugle]

Accelerator pedal position sensor. Part of your gas pedal. Need to monitor it. I would still monitor the trans solenoids at the same time, ie. . governor psi

 

[cerberusiam]

APPS is accelerator pedal position sensor, a fancy name for a TPS. Normally the ones on tyhe inside of the firewall and very stable and when they go bad they throw codes. Not always but they are a self correcting unit so when they get that far out of whack they usually code.



If the engine is actually bucking and surging something is causing a fueling issue. The fans are notorious for this when the electrcal portion goes bad. It will short or ground and throw spikes back into the engine operation system. Just like the AC clutch wire rubbing and grounding.



Ypou can disconnect the fan harness at the bottom of the shroud and drive it withotu a fan to see what happens. You could warm it up until it starts suring then disconnect to see if that will stop it also.



If you had a good scanner on it that would likely tell you the problem but if it is intermittent and only after driving for a bit and warming things up it is tough to get somebody to sit there until it happens without it costing a bunch. If something is throwing an electrical glitch into the system I would bet the speed sensor and gov pressure, maybe even temp is going whacky if you read it.

 

[LNaugle]

Where did you get the TVA at? Is this problem new with trans? Maybe try a TVA position reset and see how long it takes to come back?

 

[cerberusiam]

The TTVA doesn't control the transmission, it is just an electric TV cable. The worst you get if it doesn't set right is late shifts or early shifts. If it doesn't function correctly they throw codes. If it doesn't code it is working correctly.

The engine itself is dropping power and going to limp mode for some reason the ECU doesn't even recognize as a fault. The trans won't drop out of OD or downshift if it just looses slight power or surges. Some electrical fault is causing multiple issues to surge the engine, knock it out of OD, and force a downshift to 2nd. Those symptoms are extreme and don't happen unless there is major electrical disruption.

I would not put a bad battery past causing that type of reaction. The electronics are protected well from most external sources but not so well form their internal componeents like the fan, AC clutch, and even a floating plate in the battery. About the only external influence I have even heard that can effect them is close proximity to a boosted short wave radio.

 

[TGVET]

Wow, lots to digest here.



Halfway home yesterday afternoon I disconnected the fan clutch and for a very short period it seemed to make a difference, got up to speed passed 65, 70, 80 and settled back to 65 in cruise. It ran fine for a bit then it acted up again. When I am in cruise set at 60/1700 and I start a down grade and the speed starts to climb it starts to surge intermittently like a rapid hunting affect and then it downshifts. It will do that anytime there is a call for an adjustment to keep the set cruise speed once over 1700 rpm.



I had the batteries load checked last week, I forget the exact % CCA of each, but they were not that good and are probably ready to be replaced as they are OEM 8yrs. old. Will bite the bullet on those today.



I did reprogram the ECM with my super chips from stock back to performance tow mode and that made no difference other than I can now burn rubber. . If I want to, which I don't. .



I had the AC pump replace barely a year ago.



I'm not experiencing a drop in power or a limp mode per say. I have tried to accelerate during the time it starts to surge and get past that point but it will only downshift to a higher RPM 3000+ which freaks me out.



I've removed, burnished and De-Ox coated the negative body panel connection points as well as the engine block points.



LNaugle, I bought the TTVA from my local Transtar Industries location. The weird thing is, when I used the borrowed one off an 05 from a local transmission shop, I had no problems. I swapped it out halfway home, drove 150 miles the next day to work and back to the shop, put my OEM one back in, gave the loaner back, ordered the new one the next day. Needless to say, I am befuddled. .



I am NOT getting any codes, and NOW have a 1hour appointment Friday morning with my local Dodge dealer to take their technician with their scanner for a test drive and see if he can determine what the hay is going on. I AM DREADING THIS APPOINTMENT. I've only heard bad things happening to owners trucks resulting from the DEALER getting their hands on them. The latest being, THEY reprogram the ECM to downgrade the performance mandated by the Fed for EPA reasons. I have no way to verify that information.



Thanks again guy's for the help.

 

[AH64ID]

Having the dealership may be a good idea, it sounds like superchips doesn't write/remove a clean tune. If the OEM tune doesn't fix it then you can always put the superchips back on (or buy a Smarty). There is nothing in the latest 05 OEM flash to be scared of.

 

[LNaugle]

I read that part about the TVA which would make you think it had something to do with it... Cerb, the TVA also makes the trans downshift for passing gear right? Which is why I think there is something there... . Possible that the connection may have some corrosion in it or?? Sensors and switches that are not oem are really causing problems lately, I bought a cam sensor from napa only to have the problem reappear the next day. Bought a new cam sensor from mopar and compared the 2 with a dvom and the readings I got were half of the oem... Installed it and no more problems... . Also would look at the wiring harness that connects to the TVA because when you are swapping them out they work for awhile after...

 

[cerberusiam]

The TTVA is nothing but an electronic TV cable. All it does is ramp TV and apply pressure based on throttle position. The TTVA will only effect shifting on the 1-2 and 2-3 shift, it will not effect OD shift or the ability to hold OD, that is all under TCM control. Once the transmission shifts to OD gov pressure is ramped to max, about 110 psi, so the effect of TV pressure is negated. You can max TV pressure with the TTVA and it won't drop out of OD until the TCM says release the OD solenoid and drops gov pressure.

You could take the TTVA off the TV shaft, tie it up, to the frame, put a TV lever on it and tie it open and all that would happen is your shift points would increase. Won't effect how long OD is held.

In order for the transmission to come out of OD to drive then down shift to 2nd over 50 mph takes an electrical fault. Since he has tried 3 different TTVA's with the same result I would rule it out. A transmission problem will not cause the engine to surge like he is describing. With a steady low throttle like that it should just accelerate not surge.

Definitely a weird problem that could have many sources. I am waiting to see what a DRB will show if he can replicate it.

 

[LNaugle]

I believe it could be electrical also, plug or wires... On a 727, the kickdown makes it downshift. So why doesn't the TVA if its nothing but an electronic cable? Seems to work that way on 03s... ???? I realize gov. psi also determines this and thought was in conjunction with the sol.

 

[TGVET]

Just read the replies guy's. I'll get back to this a little later with more input from the DTT trans guy "Bill" up in Abbotsford, BC. As an afterthought, I would never deal with an out of state/non-local shop ever again. Even if they were only an hour away as is DTT. Mike at Northcoast Transmissions in Marysville, WA was VERY helpful and generous with his time rding along with me a couple weeks ago and in loaning me a customers TTVA to check again mine. What is very disturbing is with the loaner installed I had NO problems prompting me to buy the new one for 282. 00 from Transtar. Both OEM and Transtar are made buy Siemens.



Thanks again. Rob



Off to Pacific Power Batteries now for two new Exide Edge AGM's.

 

[TGVET]

Well, it wasn't the batteries but I'm glad I got new ones as the OEM at 8yrs were pretty much toast on the Amps test.

There are three speed sensors, two on the transmission and one on the rear axle and then there is the throttle position sensor. I'm hoping the dealers technician will be able to narrow it down on the road test as to what the heck is failing.

 

[ColemanR]

I had almost the same problem after a trans rebuild took almost 10k miles to figure out the govener soliniod assy was bad including the one that fixed it for about 200 miles. I was getting all those codes and I changed the batterys also. We tore in to the wiring harness changed the TTFV you name it we tried it. Changed the govenor soliniod again a second time and all was good. Hope this helps

 

[TGVET]

I'm not getting ANY codes though.

 

[TGVET]

The super chip does not go back to a real stock And I have seen the programmable choice of od off not function so who knows what else it is capable of affecting

Bob,

When the trans was rebuilt the ECM was programmed in Tow/Perf. mode. I never changed it back to Stock mode. After it was done and took it for test drive I was quite surprised at the response the truck had with the new DTT trans. It shifted VERY positive gear to gear to my surprise.



Do you have experience with the Superchips Flashpaq 3805 tuner ?

To my knowledge mine has three program settings. "Performance (No towing)" "Perf. /Tow" and "Tow mode"



As described, I reprogrammed back to stock a couple weeks ago in the troubleshooting process. All I noticed was the soft/cushy shifting again.

The other day I reprogrammed it to Perf. /Tow. I do not know of a programming feature that allows me to select "OD OFF".