Engine/Transmission (1998.5 - 2002) Overdrive issues

[JCyrbok]

Took truck into the dealer yesterday ( still have 300mile left on extended warranty) for some trans issues.



When at a moderate to light throttle, suchas as entering the highway or in a construction zone, trans will shift from 3 to OD and back quickly and repeatdedly (like every second). If u let up or add throttle it goes away and/or shift to OD correctly. This occures between speeds of 40-50mph but predominately around 45. If OD is off and running at that speed/conditions it does not do it.



Started about 3 weeks ago as an intermintant problem. On the way to the dealer I could get it to do it at will.



I should have posted this before I took it, but I am way short on time this week. I would like to figure out or atleast have an idea of the problem, incase I go to pick my truck up and do the ol' " it did nt do it for us" routine.



My knowledge of transmissions is pretty much I knew something was not right, but no clue what it is.



Any idea's? I figure solenoid or spring, but ref to above mentioned experience, LOL.



Thanks

J-

 

[JCyrbok]

Does the Diesel Dynamics True Torque power module adjust anything in the transmission, namely pressure?



I just got off of the phone with the service guy and he said that there are trans issues, but that the part that needs to be replaced ( some value) has to be authorized first. He said the tech told him that the "pressure had been turned up" on the transmission.



Other than the TTPM being on my truck occasionally, I have no other mods that I think would do anything to the pressure of the trans. The TTPM is usually run on the Timing only mode too.



Any idea's



Thanks

J-



PS how much does a DTT trans cost installed?LOL

 

[DieselRam30]

Does the Diesel Dynamics True Torque power module adjust anything in the transmission, namely pressure?

Not to my knowledge, but I could be wrong. Line pressure is usually adjusted with valve body mods. If you're still under warranty and they authorize the replacement part, you're golden.



If not, a full replacement transmission might not be necessary, but it sure is a nice addition. Either way, try to find out the condition of the rest of the trans: metal in pan?, adjustments within spec internally?, etc. before you make your decision.



I had the same problem with mine but with all the internal problems I had as well, I just went with the full DTT treatment and haven't looked back.

 

[JCyrbok]

Thanks Diesel Ram,



Last I spoke with the service writer ( is really a good guy) he said that the tech was running one final test, but not to expect any good news. \



What direction should I go on this. I have not made ANY trans mods to my truck. Should I push the issue? He advised that the part that is needed has to be released by STAR and that requires the tests that they did, and my trans failed appearantly. He advised that STAR would not release the part and would restrict the rest of my warranty.



Any ideas

thanks

J-

 

[JTeague]

Try reseting your APPS. Disconnect your batteries for about 30 min, reconnect, turn the key to run posistion with the key on, engine not running. Slowly press the throttle all of the way to the floor and slowly release it to the idle posistion. Cycle the key on/off and roadtest. This will usually fix the problem. If not, your APPS is probably going south. Some manufacturers make a noise filter to help with this problem also. Give it a try before you get your wallet out.

 

[tractorface]

Reset the APPS

I and many others have had the same exact problem. The problem is an over sensitive APPS. Reset it, I had to leave batteries disconnected overnight to make it work. Less than that did not work as well. Goerend, DTT, and others sell a noise filter that is easily installed and will filter out the noise to solve the problem. The dealers fix the problem with a reflash to make the PCM less sensitive to the changing signal. There is a TSB on it. I personally reccomend resetting the APPS (everytime you disconect the batteries) and installing the filter. Not sure how the TSB affects the feel. I can tell you that once I installed the filter from Dave Goerend the transmission shifted flawlessly. One of those deals where you don't kow how good it can be until you drive it after the fix.



Believe me I was thinking this is really bad, no simple reset and filter can fix it, but it does. See the PCM locks and unlocks the converter which is what you are feeling. It uses several signals to decide when to do this and one is the APPS signal. When you lock out overdrive you lower the speed at which the converter will lock. Not sure of exact speeds so I won't quote. There are other fixes for this as well and I have about four pages from Dave on them but everyone I have talked to has fixed with above advice.



Your not alone and you don't need a new transmission... ..... unless you need an excuse for the wife In that case I'd say the thing is shot and driving it any further will result in serious injury. :-laf

Good Luck

 

[JCyrbok]

Thanks Guys for the info. It sounds like the tech found a solinoid that was bad, which will be replaced. I will do the APPS reset and also the noise filter.



How much for the filter, how does it install etc?



Thanks again

J-

 

[tractorface]

Not sure of exact cost. Dave sent mine free since I bought a transmission. Think less than $40 from DTT or Goerend. Simply splices into wire harness at PCM. 3 wires if I remember.

 

[DieselRam30]

How much for the filter, how does it install etc?

DTT sells their's for $37. 00. For the install, I believe it's relatively simple as stated previously. However, I can't tell you for sure as I got mine put in when I got my DTT transmission.



As far as other transmission mods, that's up to you. IMHO, try the new solenoid (governor solenoid would be my guess), APPS, and noise filter before you go full on into the other stuff. That "other stuff" adds up in a hurry.

 

[ecpeters]

I had the same problem with my truck 4 years ago I had to push the dealer to replace the ECM under the 8 year 80,000 mile federal clean air act. If the truck cuts in and out of overdrive it impacts emmissions aka the 8/80,000 rlues apply.

 

[KKlingbeil]

The noise filter isn't hard to install. There are three wires, two of them splice into the pcm connecter, and the other is a ground. The directions DTT sends makes it very easy as they give wire color etc. as well as pictures.