AWD to 4x4 swap.. Trans doesn't like 4lo

[local7teener]

I have a 98 mountaineer 5.0 and i did this swap before i stumbled accross this life saving site. Well anyway i scowered every junk yard i could find to find a tcase that would fit.. 1980 ford f-150 had what i needed, a new process 208 manual shift, 2.41:1 lo range. So i got it in with the help of a grinder/cut off wheel. Well the drive shafts were a pain, but done. So now comes the problem... On my late 98 mountaineer, there is no speed sensor on the tcase. The Trans has an output speed sensor, and uses that and the abs sensors to determine speed. So when i put it in 4lo, the transmission has no idea what is going on and shifts all messed up and consequently throws codes left and right. I have read how you guys have swapped gem's to use the electric shifted ones. I was just wondering if anyone has had this problem and any good fixes..

btw the 4wd and 2wd work great, no problems, only when its in 4lo and driving does it freak out.. Thanks.

 

['97 V8]

wtf...you shouldnt be going faster then 10 in 4lo. shift it in 1st and keep it there.

 

[sparkyXplorer]

I thought on 98+ the speed sensor was on the rear end...4lo will always seems like it shifts werid since you are only doing like 5 mph..

 

[local7teener]

I had a 2001 ranger and i used to be able to go over 50 in 4lo..It shifts from first to 2nd but it hesitates at the redline for like 3 seconds then shifts and barks the tires into 2nd. I know the problem is that the computer sees the tires moving slower than the trans, making it think the trans is slipping. I guess i was wondering if i swapped out the gem to a 4wd v6, and some how put a switch to mimic the effect of turning the dial to 4wd low if that would solve the problem.. When i go to the dunes the trans get red hot laboring around in 4hi, if i could just run it in 4lo some of the time to give it a little rest.

 

[sparkyXplorer]

50mph in 4lo...

 

[ZBlackBeast]

Thats alittle quick. i dont think your tranny liked you very much... did it?

 

[local7teener]

You other guys that have the manual swap, what happens when you put it in 4lo, and then drive and take off, how it shifts, speedo??

 

[local7teener]

The tranny out lasted the whole truck, it was rolled though. You other guys that have the manual swap, what happens when you put it in 4lo, and then drive and take off, how it shifts, speedo??

 

[Turdle]

Hmmm
I went 45 in 4lo
just trying it out

It shifted fine. I have no speed sensor on my t-case or transmission-it's in the rear diffy

 

[sparkyXplorer]

I have put the BW 4406 from a like a 98 f150 and it has a 2.75:1 4lo ratio into my 99 limited 4door explorer...and I have no wires hooked up to the t-case even though there are spots to hook some sort of sensors up, but seeing that the speedo sensor on a 98+ is in the rearend, you don't have to worry about messing with the speedo teeth gear in the t-case...

When idleing in first and 4lo, even at like 3krpm my speedo doesn't read cause it is only traveling approx 3-4mph and my spedo doesn't read that...if you try and rev it higher and go faster like you said it will hold a high rpm for a few seconds then shift, and yes the shift is hard but nothing out of the normal...I have never even tried to get the tranny into third while in 4 lo

 

[CDW6212R]

Agreed, I wonder what is going on there, do you really have a trans speed sensor, those were not used past the 97 model year. I'd be looking somewhere else, the guys here know that TC you have better though.

 

[local7teener]

On the side of the tras, right behind the large wireharness (the one with the bolt holding it together) there is a 2 wire magnetic Output Shaft Speed Sensor...A tone ring in side on the outputshaft.. So speed is determined only by the abs sensor in the rear diff.?

 

[MountaineerGreen]

Your 98 should get its speed from the ABS sensor in the rear end. Did the transfer case you removed have a speed sensor connection? My 01 AWD case had no wire connections whatsoever.

 

[rwenzing]

So speed is determined only by the abs sensor in the rear diff.?

Yes, the raw vehicle speed pulse originates at the diff sensor and is sent to the 4WABS Module. Based on that raw signal, a new 0~12v square wave is generated, corrected for tire diameter. It is sent from the 4WABS Module to the speedometer, PCM, speed control, etc. Properly calibrated for tire revs/mile, that square wave will deliver 8000 pulses/mile.

Some Fords use the OSS for transmission control and for the raw vehicle speed sensor. On a 98 Ex, the OSS is only used by the PCM for transmission control.

 

[local7teener]

my awd transfer case didn't have any speed connections either.. So the v8 does have the paramaters in the computer to recognize the 4lo gear reduction even though it was never offered with a selectable transfer case? I'd like to get the wiring diagram for the selectable swich on the bezel and a gem for a v6..I guess i'll just suck it up.. I wish i could have found this site before i did this swap.. The 4406 looks like it would have been a little easier. How far is the front yolk from the input shaft on the tcase?? my issue was the yolk was alot closer to the driverside of the truck.. barley clearing the torsion bar crossmember.

 

[MountaineerGreen]

I looked a little into the wiring diagram, the F150 that the case came from has a GEM like output to the PCM to indicate it was in low range. However, I never did find such an output for even the v6 explorers. I don't know why the PCM would care if its in low range or not. It doesn't make sense that your truck doesn't like low range- I guess it did that before you swapped GEMs?

 

[Hokie]

You other guys that have the manual swap, what happens when you put it in 4lo, and then drive and take off, how it shifts, speedo??

In my '98 the 1-2 shift is weird... the computer can't quite figure out whats going on. But I usually have the truck in 1st or 2nd gear if I'm in 4Low anyway.

 

[MountaineerGreen]

That is probably because the transmission shift calculator is going by the speed sensor, and since the speed sensor isn't telling the PCM that there is enough speed to shift, it goes by some secondary input, possibly line pressure. The shifts may be weird because of that

 

[CDW6212R]

I think that would be it Evan, the PCM does have speed as a primary factor to determine shifts. I wonder what a programmer could do besides the speed control? Where's James, what else can be done with the PCM shifting programming?

 

[rwenzing]

So the v8 does have the paramaters in the computer to recognize the 4lo gear reduction even though it was never offered with a selectable transfer case?

I doubt it.