700R4 Conversion, now no 4x4

[Dignan]

So, I'm finally finishing up the 700R4 conversion on my 91 explorer. Everything seems to be passing the test (knock on wood). I have good temps and pressure. Shifts are great. The only problem I have left is the transfer case. I push the 4x4 button and get no response. I pulled the dash panel out to make sure it is plugged in tight and I checked the fuse. That stuff looks ok. Did I do something to confuse the 4x4 electronics by putting in a different tranny? Any help would be appreciated. Thanks.

 

[Maniak]

Remember that round connector on the a4ld.. You need to find the Neutral wire and make the PCM think your in neutral. Thats for 4x4 low.

I'm trying to remember if I did anything odd to just get it into 4x4..

I'll think about it tonight and see what I can remember.. I'll also see if I can dig up my notes..

~Mark

 

[Maniak]

I found some of my notes...

Under the hood I put 33 Ohm resisters (5 watt) between the Red wire and the Purple/Yellow and the Red and Orange/Yellow wires. This gets rid of the codes (unless you changed to a manual trans PCM).

On the wires going to the round connector on the a4ld I connected the Red/lt blue to the Pink...

I'll look around some more for notes..

~Mark

 

[Dignan]

This is when it stinks to be colorblind. What codes do the resisters get rid of?

 

[Maniak]

KOEO self test codes for TCC circuit (torque convert clutch) and 3/4 solenoid.

Last time my resisters burned out I got those codes in a self test.. I could have sworn I used to get them when driving (stored codes) but last time I didn't get them as stored codes.. Only on the self test thing..

When I say not stored codes, I mean it didn't throw a CEL.

btw.. for the resisters, get 5W or 10W resisters.. They are white and have text on them with the wattage and impedence (33 ohms).

BTW.. I didn't find any more notes on my conversion. . I found the instructions for AA and from what I can tell the xfer case will shift into 4x4 high even if you don't take care of your wiring.. its the 4x4 low that won't work w/out the special wiring (I have mine set to allow shifting into 4x4 low even when in gear... it doesn't normally shift when in gear but it'll try)

Before I forget.. What torque converter did you buy? Which brand/model and what stall speed is it supposed to be AND what stall speed did you end up with (my 1600 rpms stall converter is stalling at about 2700)

~Mark

 

[Dignan]

I don't know what brand/model I got. I'll have to look through my paperwork. I actually started this a long time ago, so I don't remember. I think that it was an 1800 if I remember correctly. I'm pretty much an idiot about automatic transmissions, so I don't know how to tell when it is actually stalling. Tell me what to look for and I'll let you know.

As far as the transfer case, that is what I thought about the shifting that it should still go into 4x4 high, so since its not, do you have any other ideas? Could the install have messed up anything else, or do you think it is just a coincidence that it happened around the same time? I assumed they were linked because I used to use 4x4 and now after the swap I can't, but I guess it had been quite a while since I used it before the swap. It is possible that it was actually out before I put in the tranny and just didn't notice because I didn't need 4x4.

 

[Maniak]

I'm guessing its coincidence. Search for shift motor rebuild for more info about the common problem with the xfer case. Its pretty common to hear the clicking from the back of the truck but the xfer case not move (normally you need someone to hit the button when your have your head by the winshield washer bottle on the drivers rear of the truck)..


To check your converter stall (what it is stalling at) you have two choices.

To check the flash stall just stomp on the gas from dead stop and watch how high the rpms go before you move.

To check the brake stall step on the brake and hit the gas and see how high the RPMs go. IMPORTANT: DO NOT STAND ON THE GAS/BRAKE AT THE SAME TIME FOR MORE THAN 5 SECONDS. Doing a brake stall will generate a lot of heat so wait a good 30 seconds between each test.

Some people say the brake stall wont' give you a good value becuase the engine will overpower the brakes. I don't think I've seen an automatic 4.0 OHV explorer be able to overpower the brakes when in 2wd high range. I know I can do it in low range but not in high range.

1800 is the common converter speed people sell but a 10" (required for the small case 700r4) 1800 stall converter behind a very torquey 4.0l OHV motor ends up stalling higher than 1800. Remember that the 1800 was figured out behind a 2.8 L v6 motor which has much less torque than our 4.0 OHV (which has about the same torque as a Chevy 305 V8).


~Mark

 

[Dignan]

Man, I am sorry that I haven't been on this site in so long. It has been months since you asked about the torque converter. I am sorry I never checked. I'll try to remember to do that soon.

As for the transfer case issues. I never tried to put the resister in because I figured that I need to figure out the 4x4 issue before I worry about the Low Range issue. Today something odd happened. The 4x4 and Low Range lights are coming on randomly. The car is still in 2wd (i.e. no jerking through a corner on dry pavement, obviously not in low range), but the lights come on. Pushing the buttons does nothing to the lights, which doesn't surprise me, seeing as before it didn't engage 4x4.

I was thinking about that clicking you were talking about. I don't hear a clicking. I remember that sound from Moab trips and stuff. I know what sound you're referring to, and now that I think about it, I don't think it's there. What makes that sound? That is probably my best bet to check next. Is it in the driver side panel in the rear cargo area? I hope not because that means tearing out my speakers to get to it, but it will be worth it to have 4x4 back. Plus I'm not as young as I once was, maybe its time to retire the system anyway and reclaim my cargo area.

 

[JTX]

Did you ever figure out your stall? I'm gonna order my TC in a couple weeks and need to know what stall speed is best. Any suggestions Maniak? You told me before but i deleted my pm's on accident.

 

[Maniak]

A Hughes Performance converter with a 1800ish (1600-1800) stall actually stalls at 2500+rpms.

That was the lowest stall "off the shelf" 10" (I'm pretty sure its 10") converter they had. The 60 degree 700r4 was always behind a lighter vehicle with a much weaker motor than the X has so the X will stall higher.

Hughes Performance makes converters and is actually in Tucson which is why I went with them. From all of the places I called, none had a low enough stall converter off the shelf. A few were willing to build me one.. A custom built one was closer to $500 while the off-the-shelf was about $100ish.

Some places said their 1800 stall would really stall at 1800 but they didn't know how to do the math to figure out what it would really stall by using the hp/torque curve of the engine in conjunction with the trans and gear ratio in relation to the weight of the vehicle. I stayed away from those companies..

There are only a few that actually "make" converters..

I've gotten used to the higher stall.. A friend of mine drove the X and he couldn't believe how much acceleration the X had w/out even getting "on it".. The higher stall + 3.06:1 1st gear works well.

~Mark

 

[JTX]

Sweet, thanks Mark. I'll probably just stick with a stock one, my explorer doesn't really see much street use so it should be alright. I finally found a good local builder who is gonna rebuild it and help me with any problems along the way. Im stoked to get his over with already!

 

[Dignan]

I'm still having the issue with my transfer case. I was thinking of just hotwiring the motor to see if it will turn. Mark, you said that you have yours set to shift into low range even at speed, I assume that is from modifying the wiring harness. I was thinking of doing something similar. I figure if I can tap into the wiring harness at the transfer case and make it think that I'm in neutral and then just tap a wire into the switch, I should have 4x4 back. I was looking at the wiring diagram in my Haynes manual. There appears to be a whole lot of crap going on there with speed sensors and neutral switches. I know when I'm in neutral or if I'm going too fast to shift, I don't need the wiring to determine that for me. I'm no electrical engineer and I don't fully understand the diagram, so I was wondering if someone could walk me through it a little bit. Either to test the wires as they are or to modify them to just work with the switch and the motor and eliminate all the other BS.

 

[Dignan]

Maybe it is more simple than I have been making it. The Shift Control Module isn't making the normal clicking noise from the rear cargo area. Is there a good way to check the module? I may just need to replace that.

 

[IZwack]

IMark, you said that you have yours set to shift into low range even at speed

I think you misread -- shifting from HI range to LO range is impossible because the transfer case is not synchronized and doesnt have a clutch disconnect. What Mark meant is that he's able to shift from 2HI to 4HI while on the move -- which is normal transfer case operation.

 

[Maniak]

Well.. your both right . I have the neutral wire shorted instead of through a switch.. the ECM thinks I'm always in neutral so it will always attempt to shift the transfer case (or start the truck).

It actually can't shift when moving.. but yes, I've hit the button when moving before.. so far, nothing exploded.

This wasn't my intention.. the neutral/park switch on my b&m shifter went bad, so I just bypassed the switch..

~Mark

 

[Dignan]

I don't think I have the same problem. Mine starts when in park or nuetral and not in any other gear, so the neutral switch is likely hooked up properly. I'm basically wondering if the unit in the rear cargo area that makes the clicking noises is necessary or can be bypassed or if it can be tested. I'm not hearing the clicking so I assume its bad.

 

[Brandons]

Kind of late on this, but it does sound like your 4x4 module is toasted, mine was doing the same thing, lights would randomly flicker, i believe it was a loose wire, however i just used the module from a parts truck i had. Yet to diagnose the module.

Id say check all your connections, i think theres one under the front right area of the floor under the drivers feet nearing the bottom of the dash. You might have to pull the interior out on the rear drivers side too and check the plugs on the module beside the rear washer reservoir, though i was able to reach it through the opening, others might not be able to

 

[90ranajo]

Did you ever figure out your stall? I'm gonna order my TC in a couple weeks and need to know what stall speed is best. Any suggestions Maniak? You told me before but i deleted my pm's on accident.

When I did my conversion, I ordered up a 1600 stall converter.

 

[Maniak]

Lowest "off the shelf" converter that Hughes Performance carried was 1600 which is what I got.. It actually flash stalls in the neighborhood of 2700 rpms.. It helps with the acceleration and with the torque multiplication but I spend most of the time close to 3000 rpms when driving around town.

My next one will be a custom 1200 stall converter but instead of it costing $120 it will cost around $400.

~Mark

 

[Dignan]

Kind of late on this, but it does sound like your 4x4 module is toasted, mine was doing the same thing, lights would randomly flicker, i believe it was a loose wire, however i just used the module from a parts truck i had. Yet to diagnose the module.

Id say check all your connections, i think theres one under the front right area of the floor under the drivers feet nearing the bottom of the dash. You might have to pull the interior out on the rear drivers side too and check the plugs on the module beside the rear washer reservoir, though i was able to reach it through the opening, others might not be able to

I replaced the control module and still have the problem. Anyone have any other ideas?