4x4 lo question

[JamesVW73]

so i have a 92 explorer, manual transfer case, manual hubs. ive noticed if i shift my transfer case into 4by lo, the transmission only shifts into 1st and 2nd gear, and nothing farther. is there any mod that anyone knows of to fool the computer into actually upshifting like normal through ALL the gears?

 

[MountaineerGreen]

Why would you want to do so? I don't think 4low in the transfer case in intended for much speed.

 

[JamesVW73]

Why would you want to do so? I don't think 4low in the transfer case in intended for much speed.

at the moment, my truck has 33s and 3.27 gears. i am trying to not burn up my trans while waiting for my gears. thought if i could get the trans to shift through all the gears in 4 lo it would but LESS stress on the trans. keep in mind this will be 45mph or less around town

 

[MountaineerGreen]

I'd just buy gears, you are asking for trouble driving in 4low. The transfer case can get too hot and grenade it.

 

[JamesVW73]

well, ive already bought gears, and im just waiting on them and the locker to get here. it seems like its taking foreverrrrrrrrrrrrrrrrrrrrrrr

 

[schmidlkofer]

45 mph in 4 low....not a good idea. and shoot dry pavement ant turns will just ruin your t case.

 

[JamesVW73]

true, i'll just stick with real easy driving until the 4.56s and the locker come in

 

[schmidlkofer]

good idea.

 

[gijoecam]

I can't speak for the first gens, but I know second gens are capable of speeds up to 55-60 mph depending on tire size and rear axle ratio. (admittedly, that's at red-line in OD)

My F-150 bounces off the limiter at 68mph. (Drag racing in the sand)

-Joe

 

[Charlie]

My second gen hits the limiter at 75 mph

 

[IZwack]

Wow, and I thought I was pushing the limits when I run the trails at 20 MPH in 4LO

 

[Charlie]

Wow, and I thought I was pushing the limits when I run the trails at 20 MPH in 4LO

Just because it CAN doesn't mean it SHOULD

 

[gijoecam]

It's simple math really....

{ Redline x (1/overdrive ratio) x (1/transfer case ratio) x (1/final drive ratio) x (pi * tire diameter) * 60 } / 63360

In my case,
5000 RPM x (1/.75) x (1/2.48) x (1/4.10) x 30 x pi x 60 / 63360

=59.72 mph

Now, run it in high range, and you get

5000 RPM x (1/.75) x (1/1) x (1/4.10) x 30 x pi x 60 / 63360

giving a theoretical top speed of 145 mph.

Now, if you're running in low range with a 3.73 rear end and 33" tires,

5000 RPM x (1/.75) x (1/2.43) x (1/3.73) x 33 x pi x 60 / 63360
=65.69 mph


Useless info... I'm bored at work LOL!!

-Joe

 

[Charlie]

I did a calculation last year for the theoretical top speed, but got something more like 160 mph. Mine wasn't as thorough as yours, though. Yours looks a lot better.

 

[fischerry]

when in 4low there are only 2 gears.with a automatic transmission.manual might be diffrent.but i wouldnt see why.

 

[JamesVW73]

when in 4low there are only 2 gears.with a automatic transmission.manual might be diffrent.but i wouldnt see why.

see thats what im trying to change, the auto shifts just like normal, just first and second gear. its electronic somehow, the transfer case tells the computer you are in 4lo, so it only uses the first 2 gears, 4 hi does not do this.

 

[MrShorty]

when in 4low there are only 2 gears.with a automatic transmission.manual might be diffrent.but i wouldnt see why.

My '92 will shift through three gears 1, 2, and 3. Never gets fast enough to want 4th gear. Granted in 4L, it doesn't stay in 1st gear very long, but there are definitely 2 shifts.

If you only have two gears, which two do you have? Is it starting out in 2nd, so that you only have 2 and 3? Or is it never shifting into 3rd (stuck in 1 and 2)? Recognize that on the A4LD, 1-2 and 2-3 shifts are both hydraulically controlled.

 

[JamesVW73]

lol then yeah, i was wrong, it is the first 3 forward gears lol, just no overdrive.

 

[MrShorty]

I've been tempted a few times to wire a switch into the 3-4 shift solenoid circuit (and maybe even the TCC solenoid circuit) so I can manually force the 3-4 shift when in low range. It's a fairly simple ground side switched circuit.