Engine/Transmission (1994 - 1998) auto transmision

[vc]

when going down the highway-flatland- and then a bridge comes along and the fueling to engine goes up to maintain speed with cruise control on. I notice that the rpms might actually increase about 125 rpms while the speed stays constant. I'm thinking that it should stay the same when in overdrive at constant speed. Does this sound right, and if so does this mean my torque converter is starting ti slip a little?

Thanks for info.

vc

 

[phoekema]

slipping converter

Yes, it would appear your converter lockup clutch is slipping a bit. No matter how hard the engine is working, at a constant speed the rpm should not change. It's a real shame Mopar has one of the very best diesel engines available and didn't do anything to supply an automatic of comperable quality. Because of a similar problem on my '98. 5 after putting in bigger injectors, I installed a ATS converter & valve body. It works extremely well now, but idealy I shouldn't have had to do that.

 

[DavidGardner]

VC

Yup sounds like the converter is slipping. I see by your sig that you have some upgrades in power. You need to invest in an upgraded trans. I have the DTT stuff and am very happy but have also heard good things about ATT. Your choice, but the time is here. Good luck on which ever way you go.



Dave G.

 

[amsoilman]

There is nothing wrong with the automatic transmission in the Dodge... ... ... ... ... . if you keep the engine stock! The transmission will hold up under "normal" conditions. Its usually the TCC that goes due to the increase in HP and Torque, and not the transmission. I have seen several go over 200,000 miles before they need repair. Just drove one today that has 176,000 and it was still functioning well.



I don't understand why people have to complain about a product that was designed for a given amount of power, then increase the power and expect it to hold up under those cercumstances.



Bottom line... ... ... ... ... ... If your going to upgrade and add more power, upgrade the drive system as well, as someone else suggested.

"Of course this is my opinion"



Wayne

 

[Bandit1]

completely stock my transmission began to burn out at 50k, never towed anything i guess i got a lemon. one of my buddies has 217k on his with power turned up and used to tow a 5er, jsut depends on the transmission.

 

[Dave Remillard]

I'm with bandit 1 on this one. My stock transmission started acting up at under 50K. Also with little towing and only a 2K camper on occassion. Must be at least two of us with lemons. The last Dodge I bought prior to the one I have now was back in 1973. It was only because of the Cummins that I even considered another Dodge. The one in "73" was by far the worst vehicle I have ever owned . Dang I like this Cummins though. D. C. could take a lesson from a competitor and put an Allison or something else in their trucks that is proven dependable. That would no doubt lead to more repeat customers. All of this is of course M. H. O.

 

[phoekema]

don't agree

Amsoilman,

I would respectfully dissagree with you re: the Dodge auto transmission. It is only because the transmission is a weak link, that the Cummins must be down-graded in the first place when you order an automatic. It is a fact that the stock manual has more horsepower than the automatic... ... ... ... ... . only one reason for that... ... ..... the automatic in stock form is not up to the task.



To me, this is a shame. Especially now that GM has a very good automatic and the early reports on the Ford show their new auto to be much better than the stock Mopar as well. I, as I mentioned before, have upgraded my auto and am very satisfied. If the engine were not down-graded in the first place (a penalty to me for opting for the auto), it is likely I would not have upgraded either the transmission or engine.



As you mentioned, we all have our opinion, however if you were to take a poll I would guess most would not be overly impressed with the stock auto provided by Dodge. Now that the competition has improved so much, Dodge MUST do better or loose sales.

 

[jwalton]

It's unfortunate that we have to agree on the transmission issue. When i bought mine the guy gave me the certificate that showed it had been rebuilt and new converter. Whole truck stock. I forget how many miles later, It left my wife stranded in Lancaster. Had to pull it home with the Chebby. She was totally imbarassed . Still stock.

 

[Pit Bull]

I think Amsoilman, is right about these transmissions 9 times out of 10. It's that 10th time that cost me $1700 for the extended warranty to cover the entire truck to 100K miles. If I would of been better informed at the time I would of kept the $1700 and used it at a later date to upgrade the transmission. I just hope that if I have a bad transmission that it goes out before I am out of warranty . I drive 20K miles a year so I now have 55K miles on the truck. Two more years of covered driving. If it goes out I will have DC fix it and then take it and get it upgraded. At that time the bombing can begin, if I have any money left

 

[vc]

Thanks for info gents. I didn't think the auto should be changing rpms in o. d. while maintining a constant speed. I guess this years bonus might be partly spent already

vc

 

[98rammer]

you can see the mods in my truck signature. if you're slipping it, you may want to think about a torque converter unlock switch like i have. i keep it unlocked until i'm above 70mph.

 

[shendren]

sounds like your tps. pull the wires out of the harness.

 

[copp]

Guys i think vc has a bad TPS switch . When that kicks out of overdrive even for 1 or 2 seconds the rpm's increase while the speed stays the same. mine did it at highway speeds until i replaced the TPS . You can try cleaning it with contact spray first before you get reamed for $150 for the new part . hope this helps ! see ya , shorty

 

[Joe G.]

vc,



Does it feel kind of like a shift when the RPM raises or drops? If so then you may have a TPS problem. If it feels real smooth then it's likely that you have a slippage problem. It might be hard to tell the difference, but if you can that might help locate the problem.



You might try fooling around with the trottle without the cruise control and try to duplicate the problem. I tend to think you have a TPS problem.

 

[vc]

Joe G. ,

It definitely does not feel like it's shifting - or should I say downshifting. A little more info. This past weekend I was returning home from vacation with boat in tow. I had the cruise control set at 65 mph most of the trip of 450 miles, with the last 100 or so miles at 68 mph. At this speed there was no downshift going up bridges as I would have hit the o/d off button if it was going to be doing that. Once going the other way two weeks earlier I was in o/d at a slower speedd - about 55 mph when I came on a bridge and it downshifted and boy could I tell it did. Big change in rpms in addition to the engine sound changing with it.

Anyways, coming home and when going up a bridge, the engine would get more fuel to maintain speed on the cruise control. The boost would go up a good bit, the rpms would stay constant until the boost was nearing its peak and then I could see it rise up aprrox 125 - 150 rpms at most. Then when nearing the hump of the bridge the rpms would return to where they were and the boost would start back down. And if it makes any difference, the boat/ trailer weighed about 8200 lbs that night.

thanks for help guys - keep it coming.

vc

 

[vc]

And on a side note, I notice no changes in rpms when not towing - only under the heavy towed load when suddenly burdened more by the terrain.



Another transmission question for my brother. Do you all know what check valve is the one that lets the fluid leak back overnight when parked so that when you start up in morning you have to wait a minute for fluid to get pumped back up so truck will move. His is a gasser Dodge about a year old if that, and the dealer told him they added half a quart of fluid and all is well again. Well needles to say that was a bunch of bull. It did not need fluid and it still leaks down. I thought I remembered some here with same problem and it was a check valve in the valve body or t/c leaking. Can you point me right direction to tell my brother?

Thanks again.

vc

 

[Joe G.]

That sounds like the TCC slipping alright. Best to fix it before it fills up the VB with trash and makes things worse. It doesn't sound bad yet, but there are no hills that I know of in FL. You might fix it by turning up the line pressure. I think DTT has instructions on how to do that on their web site.



About the overnight drain back. Don't fix it if it ain't broke. That's normal behavior for a torqueflite transmission. Just let it idle a little in D when you first start up. That will fill the TC and it should be good for the rest of the day. My Dad's '63 Plymouth muscle car did the same thing. My truck does it. My '82 Imperial does it. A check valve will cut it down some but that causes higher temps in the trans because of the restriction in cooler line flow. One of the first things the aftermarket trans people do is remove the check valve if the truck has one. Some of the trucks do because of complaints like your brothers. It's in a cooler line.

 

[shendren]

did you pull the tps wires out of the harness yet. this is your problem... ...

 

[phoekema]

not likely tps

I don't agree with the tps solution in this case. If the lockup clutch were unlocking at times due to a tps problem, there would be a lot more than 100-125 rpm change. I grant you the tps is a potential problem, but it doesn't sound like it is the culprit in this case.



Another short term solution might be the aftermarket linkage kit (I think BD sells it) that fools the transmission into providing higher pressures at lower throttle possitions. Not a long term solution, but it might buy you some time.

 

[shendren]

my tps problems were making it jump 100-300 rpm... ...