Bought an 01 Screw a couple of months ago and been having trouble getting up my steep driveway here in the mountains. First I need to say I bought it in Cheyenne WY and drove it non-stop home to northern New Mexico (450 miles) w/o any problems. Run great and handled the mountains on I25 with no problem. Now I can't hardly get it up my drive until today. It always felt like it wasn't down shifting to low to go up. Yesterday I moved the column shifter into low and like to never made it up the drive. I've long been suspecting it wasn't down shifting to low but wasn't sure. When I bought it I had to do the zip tie under the dash and since then the column indicates I'm in low. Today when I got back home from the post office I stopped and put it in 4x4 low and it came right up the drive no problem just like it should. Since I've never messed with truck trannys I now wonder is the tranny OK and it's just a down shift to low a problem. Fluid isn't low and smells good but I ordered a filter kit any way and will be changing it and the fluid later this week. Any help would be greatly appreciated.

 

Is the problem possibly caused by a shift solenoid?

 

Is your trans throwing codes? Is your O/D Off light flashing?

 

No it isn't.

 

Probably not the electronics then.

 

I don't understand why it works great in 4x4 low but doesn't appear to downshift into low when trying to come up the drive.

 

UPDATE: I warmed the truck up today and checked the fluid. It's on the mark but slightly dirty and a slight burnt smell. Ordered a filter kit from Rockauto and will change it and the fluid when it comes in. Never saw a code so plugged in the scanner to check it and no output. Replaced fuse #3 then checked it. No codes stored or hidden so eliminates the shift solenoid. Will give an update after changing fluid and filter.

 

Wouldn't that be because the transfer case is shifting into a lower gear and NOT the transmission ?

 

I don't know if that's the case or not. I really don't know much about trannys. Will take someone much smarter than me to confirm that. Thanks!

 

Does the truck feel the same in 2 and 1? I'm fairly certain on 4R70Ws the gear shift moves a valve that manually overrides the solenoids (electronics) and holds a gear. Switching to D gives the electronics control again and gives you 1, 2, 3, and 4(OD). Turning OD off via the button on the shifter disables 4th gear and should usually be set to off if you're going in steep mountainous terrain or towing.

You should have more off-the-line torque in 1 than in 2.

If 1 doesn't hold 1st gear there's either a tranny issue or shift cable issue. If the trans does shift into 1 via the gearshift (cable) that would lead me to believe either a shift solenoid is going out or there's an issue with the throttle position sensor or throttle cable and the trans isn't seeing the input from the pedal (can't shift down to first if it's not told the driver wants to).

If none of the above will get you to go into first gear that would make me think clutches are bad.

Side note: 4-low switches gears in the t case and you have the trans in neutral to active it. This is a different "low" than 1st gear. The light on the dash only comes on when in 4x4 Low.