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Ram Torque Converter Lockup Switch Notes

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Forcing TC Lockup         Disabling TC Lockup  

The TST and TDR sites have instructions and wirting diagrams.


Torque Converter Lockup Switch Warning

From:   Brian Roth <74763.45@compuserve.com>

We are taking a stand on the convertor clutch lock up when used on acceleration.  The amount of torque available at 1700 rpm on the stock engine can cause the stock fibre to slip and burn. If you are developing more than 500 lbs ft of torque consider it burnt toast.

Brian Roth

BD Engine Brake & Valley Fuel Injection
Sister Co's in Diesel Technology
http://www.bd-vfi.com/valleyfuel.html


Manually Controlling Torque Converter Lockup

DiRT mailing list discussion   June/July 1998

> Am  I the only one that is going crazy with the excessive T/C slippage.
> Has anyone installed a BD converter?

From:   Drdonnelly@aol.com
I suggest you read the info on the TST website (http://www.tstproducts.com)

In brief, the torque converter lockup switch helps, and the BD does lower stall speed.  TST is currently looking into the possibility of even tighter stall converters.  Try the lockup switch first, it is basically "free".

> if you install the switch, do you have to always switch the torque converter on/off?

From:  "Stevan Gajic" <toe_ball@hotmail.com>
Nope. When you engage the TC lockup switch, you get stuck in 3rd/4th gear and the TC locks. When you dis-engage the switch, the tranny resumes normal operation.
 
From:   Mikie <mbeatty@worldnet.att.net>
What is happening with the switch is that the lockup solenoid has battery to it all the time. When the CPU thinks it's time to lock the converter, it applies a ground to one lead to the solenoid.  What the switch does is fool the solenoid into locking up the converter.

> I don't need to use the lockup switch all the time (thus it locking at
> 50mph+ is fine with me) I only  need it sometimes. If the switch is
> off, will the converter still lockup normally, or will i have to lock the
> TC all the time?

From:   Mikie <mbeatty@worldnet.att.net>
I can't say for the 96 up, with the relay jumper, but if it is the same as with my 94, with the switch off, it works NORMAL.  The switch puts the ground on that the CPU would  normally do at the right speed and load conditions.

If I remember correctly, I could manually downshift to 2nd, but it was very harsh as stated in the TST text.  Kinda like shifting without a clutch. :(

> The instructions mention replacing the transmission relay with a jumper.
> What is the purpose of the relay ? (since the '94-'95s don't have one)
> What harm will be done by leaving that circuit activated all the time?
> I have no need for this lockup switch when I am NOT towing so I guess I
> will have to replace the relay for normal driving.

From:    Drdonnelly@aol.com
the way the lockup switch works is this:  there is an orange/black wire from the computer that is essentially the ground for the torque converter switch in the tranny, and it is grounded only when the computer wants the converter to lock up.  You splice into this wire and run through a switch to another ground on the truck.  that way you can lock up the converter when you want to, in 2nd or higher gears in most cases.  If you don't flip this switch on, the lockup works as before.

> ok but what purpose does the relay jumper serve?

From:   Drdonnelly@aol.com
if you leave the relay in, you cannot lock up the converter in lower gears. You can use the jumper and leave the switch off and the truck will run as before.

> Why does CC put in a relay (on the later models) if  the truck
> will operate normally with only the jumper?

From:   Drdonnelly@aol.com
they don't want it be able to lock up until in high gear (4th or 3rd if OD is locked out).  the relay provides this function.

Later Notes:

Subject:  T/C lock up switch
Date:      Sun, 28 Mar 1999 18:36:41 -0600
From:     Dick Graham <rgraham@ont.com>
To:         turbo diesel <turbodiesel>

Most of you may already know this but when installing the TST version of the TC lockup switch on my 1998 ISB the orange black wire that you tap into runs through part of the harness breakout behind the engine.  The harness heads right straight down to the transmission and is a convenient place to tap into this wire.  Simply get an 18 gauge parallel splicer from Radio Shack with silicone grease already in it and lay it next to the tranny wire.  Also lay the wire to your switch into it, crimp it together and thread it through the firewall.  Wire to your switch, wire the other contact on your switch to ground and you're there.  Works great!

Thanks,

Dick


Disabling Torque Converter Lockup

From:   Mikie <mbeatty@worldnet.att.net>
I've done this to mine in two ways.  A momentary foot switch to disengage the cruise control and converter without putting on the brake lights, and a on/off switch to leave the converter un-locked for those times when OD/locked is to high and 3rd/locked is to low.

I spliced the foot switch into the wires going to the brake switch and the on/off switch to the wires going to the converter lockup solenoid. I do notice the engine temp going up about the thickness of the needle when running un-locked for several miles.

> The diagram that is in the TDR article show a 3-position switch (?).  Does
> the middle position mean "off" as in "unlocked" for the converter. If so, I can
> use that setup, or else I'll use the simple solution above, suggested by Mikie.

A three position switch with a "center off" will completely disable torque converter lockup in the center position. This may, in some circumstances, set a fault code in the PCM.  -  Dave

> a while back someone mentioned TDR article about
> wiring a switch to disabling the torque converter lockup.
> Can someone please provide details.

From:   Drdonnelly@aol.com
I note you want to disable the lockup.  Well, the TST stuff is about manual lockup to supplement the computerized lockup, not about disabling it. However, once you locate the orange/black wire, instead of splicing into it a second ground for manual lockup, you could cut the wire and run three leads--orange/black from computer to switch, orange/black from switch to transmission, and whatever color from switch to auxiliary ground.  then you could choose a switch setup to give no ground even if the computer wants to do so--this would disable the lockup as you asked (assuming that is really what you want).

From:   Mikie <mbeatty@worldnet.att.net>
I've done this to mine in two ways.  A momentary foot switch to disengage the cruise control and converter without putting on the brake lights, and a on/off switch to leave the converter un-locked for those times when OD/locked is to high and 3rd/locked is to low.

I spliced the foot switch into the wires going to the brake switch and the on/off switch to the wires going to the converter lockup solenoid. I do notice the engine temp going up about the thickness of the needle when running un-locked for several miles.


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Last Update August 12, 1998