OK guys just got a 97' 2500 4x4 Dodge CTD. When i am driving it though it seems like right when it ***** into over drive it locks the torque convertor up and dropw to about 1500 rpm and really starts to pull and lug the engine down somewhat. The engine takes it though and really gets going. I am pretty sure this is not supposed to happen, but i could be wrong. So what would cause this, and about the valet switch when would you lock the torque convertor up, only in overdrive?

 

You mixed terms
A valet switch controls an air solenoid on the AFC boost line. Block boost pressure to the AFC and you limit fueling.

A 3 way TC lockup switch is what you want. Allows normal, locked off, and locked on TC clutch.

Your description sounds fairly normal for a stock set-up.

 

Well right when it shifts into overdrive it locks the TC up and drops like a 800-1000 rpm. There is no time that it stays into overdrive then locks the TC up, is that normal?

 

O and thanks for the info. How would i go about getting or making the 3 way TC lockup on, off, normal

 

From the big rpm drop you have a stock (slop) converter and applying some power. Is this a normal shift or when you use the O/D lock out button?
Without the O/D lock out and moderate power, mine will shift into O/D around 40-45 mph, but not lockup until around 55-60 mph. Using the O/D lockout if I am holding steady around 50 mph and release the lock out it will drop to O/D and then lock up in quick succession.

Is the truck stock or have some mods?
Perhaps check the TPS voltage and tranny kick down cable.

 

Yeah it pretty much does what you were saying yours does. i thought it was odd when we were accelerating onto the free way it just would shift into over drive at 50 then at 55 lock up. I thought it wasn't right because it not really lugged the engine but made it do some work that wasn't normal as compared to other gears. I did try it without OD then pressed it at around 50 or so and it locked up in sequential order. Does the torque convertor only lock up in 4th and 5th or in all gears when it is operating in normal. How would you use the 3 way TC deal, and what are the reasons behind it for using it?

 

It sounds like your tps could need adjusting. The tps controls the lockup in 3rd gear( OD turn off) or 4thgear lockup
A lockup swith makes the tc shift locked up between shifts but will stall the truck out if you come to a stop so you have to turn it off to factory position(2 way switch) the 3 way switch makes it where the converter wont lockup Ive heard some people like it for city driving. Do a search for Lockup switch and you can see whats involved.

 

I was replying to your question on the 3 way switch when the computer locked up. Now, I cannot open PDF to check the wire number in the instructions

Here is instructions for a single auto, lock switch http://www.tstproducts.com/Torque%20...p%20Switch.pdf

Adding the "off" mode requires cutting the indicated wire and soldering wire extenders on each cut end and running them into the cab. The wire from the TC solenoid goes to the common of a on-off-on double pole switch. The second wire to the PCM goes terminal A. A ground wire goes to terminal B.

The converter will lock in 2 factory modes. 4th (O/D) or in 3rd with the O/D lock out button active. With a lockup switch you may get 2nd gear. My valve body is modified to lockup in all forward gears.

Check your TPS voltage. If it does not go high enough the converter will lock too fast with moderate power applied.

 

How would i check the TPS voltage. What is the TPS? and what should it read. If it is low how would you fix it.

Thanks for all the help, my dad called hughs performance today and the guy said they sell a 3 disk TC along with other parts for 1360$. They said the TC should be good for 700+ hp. He said they turn it into a Peterbuilt Transmission meaning it was really beefy with some 70lbs plate in it. Fueling Around, have you heard anything about them?

Thanks Adam

 

the 500-800 rpm drop you are referring to is not a shift from D to OD. that is just the converter locking into over drive it is already in OD but the engine spins alot faster b/c the converter cant put it to the tranny (and then to the ground) and when it locks it has no choice. so you drop 500-800 rpm because the converter is slipping that much. The 3 disc converter is probly the best thing you can do for your problem (valve body should be done too since your tranny is already out) up the line pressure and really put it ot the ground. It shouldnt be too much more if you do it all at once and it will really be worth it. I got my tranny done with a converter and all for $1500 and its good to 500hp. you might spend a little more if its not a close friend workin at the shop. The 3 disc converter will also be able to handle a manual lock up switch down the road... a few mods would make it really cool!

 

How would i actually test to see if the tc is actually slipping. Not to say your wrong but just have never felt a tc slipping so i wouldn't want to look for or feel when i am driving, even hear. It shifts smoothly.

 

TPS location


Use the search feature and find a thread on TPs voltage.

I've heard of Hughes Performance, but don't know anything about the products.

-John

 

TC slipping is when your TC is locked (drive or OD) and you mash it and your RPMS go up and your speed only increases marginally hence there is slipping and the first thing to slip is the stock TC. It just feels like youre not puttin all your power to the ground when you should.