Lock-up Mod

[chuckster57]

I Think I should have done the mod before we left. Correct me if I'm wrong, but the converter is NOT locked while I am pulling up a hill @30 MPH in second gear right? If so then that might explain the high temp I hit on the LONG pass.

Here's my ? If the L/U mod would help, Can someone refresh my memory on what color wire I ground in the trans harness?

[PowerstrokeConverters]

Diff trucks but mine does NOT lock before 42-45 MPH.....I think it only locks in OD, I am planning on buying a electronic control module that lets me adjust it, but your tranny prob. does not have any of the electronics that mine does, but I could be dead wrong so.....anybody?

[chuckster57]

Yeah they are different, I have an E4OD. IIRC it Locks at @ 37 MPH.If O/D off also unlocks, then I think the mod would be a good thing. I am only 4 days into a 6 week trip and I haven't encountered these types of hills with this truck.

[chuckster57]

I found an old post I did about the mod and it says to find the purple/yellow wire in the harness leaving the transmission. I can't find any wire that color combo even after cleaning them up real good. The directions I have are for a '96. The E4OD is the same for those years right? did they change wire colors? I am due to leave early in the AM so any help would be great...Thanks

[88beast]

that kid my age a while back did it to his truck
he now moved to the psds cause he got a psd so find him?
sorry i gota c6 so i cant do the mod

[Fozz]

I just did this mod this week. It is the purple wire with yellow stripe. I cut mine where the harness comes down the frame under the drivers seat. I wired it with a three postion dptp swith (on-off center-on) so I can manually lock it, run with no lock up or normal, with light indications Be careful, there were two purple/orange stripe wires in my bundle. Make sure you cut the right one. After cutting, you want to ground the wire from the tranny to lock it up. Make sure you unlock it under 35-40 mph, especially before coming to a stop.

[BLOWINSMOKE99STROKE]

now my question is can this be done on an early 99? im having some trans issues and it feels like my torque converter is just unlocking, cant get over 35-40 sometimes. so if i could do this and milk it for 2-3 months ill be able to afford a real nice like tranny!

[M.L.S.C.]

The wire is indeed purple with a yellow tracer, there is only one of those in the harness, the other one Fozz is talking about has a different color tracer. Factory settings of the PCM command a converter lockup shortly after upshift to 3rd (feels like another shift), and nearly instant lockup upon upshifting into OD (that one can't be felt easily). If you accelerate at moderate throttle you'll count 4 upshifts: 1->2, 2->3, 3->3lock, 3lock->4lock. PCM commands converter unlock under heavy throttle (3/4 throttle or so), upon complete release of throttle pedal, whenever brakes are applied, and upon downshifting into 2nd gear. I run a manual switch for two main reasons:
- I hate the 3lock->4lock upshift at 35mph, it drops my engine speed down to nearly 1100 rpms, which combined with an uphill makes for lots of smoke till I hit 1600 rpms.
- upon release of throttle and converter unlock there's little to no engine braking available, leading to heavy used of wheel brakes on long downhills and potential glazing and burnup of pads and shoes. I have my converter wired up to a switch on my shifter, I also have the OD control button moved to the same location ('89-'91 trucks have the darn thing on the dash, very stupid idea IMHO), so I can operate both with the same hand and very quickly. I have a SPDT (5-pole) relay wired in the converter wiring between the transmission and the switch on the shifter, the relay is triggered by the BOO switch and opens unlocks the converter for me whenever I hit the brake pedal. If often manual switch operation is expected, a "dummy converter" must be created and it's signal must be fed back to the PCM to prevent it from detecting a converter circuit failure and entering "limp" mode - I have my PCM totally disconnected from my converter, I feed the PCM 12V key-on through a 22k-ohm resistor and it is very happy with it and leaves me and my manual converter switch do our thing. Additionally, the 35-40mph threshold Fozz mentioned is a bit high, I run around town with the OD off and converter locked like all the time - above 30 mph and I lock it up, under 30 mph and I unlock. Overall I'm loving the manual lockup switch, I drive over some 8% hills and going downhill idling at 2400 rpms in 3rd gear with the converter locked allows me to safely maintain speed without ever touching the wheel brakes, which means that unlike the gassers who ride on the brakes all the way down when we hit the bottom of the hill I have nice and cold brakes and I can stop on a dime, while they have severely degraded braking performance cause everything in their wheels is about to start glowing

[chuckster57]

for the respones guys. Looks like I might not be able to do it during this trip. I don't have all the time and tools. I do have an on/off switch wired up to gnd, and the other end hanging on the harness at the tail shaft. Since I am the only one that drives the truck I am not worried about a multi position switch. I thought all I had to do was tap into the purple/yellow wire, so when I throw the swich it would lock the converter. Sorry about the lag on responses too....My laptop didn't like the updates I did before we left and I had to spend a few hours repairing the O/S (windows xp home).

[M.L.S.C.]

Chuck, you can definitely just tap in the harness and ground it whenever you want the converter locked. Problem is sometimes (only sometimes and for some people) the PCM does not detect the converter unlocking when it commands it to (cause you have the switch on) and it goes nuts and throws the trans into limp mode. Again, this don't happen with everyone's truck, so by all means go ahead and run your setup, and if she ever goes into limp mode just disconnect the batteries and let the PCM reset itself. I have the resistor cause of how much stuff I got hooked up to my batteries, and I can't just go and reset the PCM every time it goes silly on me, and with my luck I just know that will happen abut every day I drive the thing, lol

[chuckster57]

Thanks again. I will have to convince the wife to climb under with me to I.D. the wire as my color vision isn't that great

I will post up when I do it and let you know how it went.

[cre8ive]

Just went on a trip to Avi (between Havasu and Laughlin on the Colorado River) w/ the camper and bass boat. Several long hills, and 100 + degree OAT. I did experience some hot temps in the trans and the engine from time to time. I learned that if I keep the gears lower and the RPM's up around 2200-2400 on those long inclines, the temps were lower overall.

Last night we took the truck empty to the Barstow Drive-in movie, and the TC was continually locking and unlocking when I had the Over/Under engaged, but was much better when O/U was off.
Having read several threads on the lock-up mod, I've been unsuccessful at finding the Purple wire w/ Yellow tracer coming off the right side of the trans. I have an E4OD, w/ a Banks TransCommand. Should the Purple wire still be here somewhere, or should I be looking for a different wire?
If I connect at the harness on the driver's side whell well, which bundle or where does the bundle go so that I can narrow down my search?
I want to do the mod, and then drain, flush and replace the filter and all tranny fluid including the cooler and TC. Transmission was rebuilt about 15K miles ago and has worked great until the last trip.

[88beast]

you have a gv on a e4od thats useless without the mod
youre banks trans command could be hiding the wire or at least have moved it over a bit
but as i understand the wire comes out of the tranny so just tap into it under the truck

[M.L.S.C.]

You can tap into the wire at the firewall connectors, but so far I have been unable to locate it there - I cut it above the crossmember as that was the easiest area to access the harness. Please refer to Banks Trans-Command installation manual here:

http://assets.bankspower.com/manuals/188/96370.pdf

Figure 2 on page 4 shows you the location of the plug at the end of the transmission control harness, and figure 3 on page 5 shows the pin numbers of the plug - pin #4 is the one for the TCC lockup, that's the one the purple/yellow wire terminates at. The Trans-Command unit does not alter that part of the harness connector, it seems to me it only taps into the main 12V power and the EPC control wires, so it essentially piggybacks to the factory PCM and only alters line pressure through the EPC solenoid.

[cre8ive]

Stupid is as stupid does, I guess. Very humbled by your last post Mr. M.L.S.C.. I was looking at the cable between the trans and Trans command... sheeeeeesh! You'd never guess I used to fix missiles and unmanned aircraft, and in electronics at that! Anyway, the link helped me realize my mistake, and I found the purple wire and tapped in right where Fozz did.
I ran the wire up to the dash alongside the cable bundle and connected it to a switch and a light. I have +12V to 1 side of the light, and ground to 1 side of the switch. The neg side of the light, and the wire to the trans are tied together and go to the other side of the switch. This way, the light is lit when the TC is locked from the PCM, and off when it's not. When I throw the switch to manually lockup the TC, the light stays on.

I just did a test drive and first thing is, the truck wouldn't start with the key. With key on, I can start it by jumping the solenoid on the firewall. 2nd thing, I don't have normal overdrive from the trans, but do have it from the GV Over/Under. I disconnected the wires from the switch and light, but still have both problems.

Q1: Could these 2 problems be from something I did inadvertantly while messin' around with O'l Bess' parts or or just a coincidence?

Q2: What could I have done wrong to cause these 2 problems?

Q3: Should I not have OD with this mod?

Fortunately, I have time to work on it next weekend.