Transmission will not shift into 3rd gear

On the transfer case
Transfer Case - Electronic Shift
The four-wheel drive electronic shift-on-the-fly feature electrically shifts the vehicle transfer case between 2WD, 4WD HIGH, and 4WD LOW. The system mode is selected by the operator through the mode select switch (MSS) on the instrument panel. The operator is informed which mode the system is in by two instrument cluster indicators: one for 4WD HIGH which appears as 4WD, and one for 4WD LOW, which appears as 4WD LOW. Shifts into 4WD HIGH can be made at any speed. When shifting into 4WD HIGH with the vehicle stationary, tooth blockage may occur preventing shift completion. When the vehicle is driven above 8 km/h (5 mph) the shift will complete. When shifting in or out of 4WD LOW, the four-wheel drive (4WD) control module requires that the vehicle speed be less than 5 km/h (3 mph), the brake pedal be applied, and the transmission be in NEUTRAL (automatic transmission) or the clutch pedal be depressed (manual transmission).
The gearmotor encoder assembly is mounted externally on the transfer case. It drives a rotary cam which moves the mode fork and range fork within the transfer case between the 4WD HIGH, 4WD LOW, and 2WD range positions.
The four-wheel drive (4WD) control module controls the gearmotor encoder assembly that shifts between 4WD HIGH, 4WD LOW, and 2WD modes.

Hi Ralph.

I do not own a Durango, but have owned many 4WD vehicles and can offer tips for proper usage.

The "L" and "H" after the 4 and 2 stand for "Low" and "High" ranges. The 2 and 4 stand for the number of wheels that can receive power from the engine and transmission. Most 4WD vehicles only provide power to 1 wheel on each axle (front at rear for a total of just 2 wheels powered) at any given time (but for purposes of discussion, we'll call it 2WD & 4WD, as advertised).

Generally, "2WD" is only offered as a High range and is the same as a "normal" 2WD car or truck. I haven't seen a car or small truck that offers 2L (but I haven't seen a Durango - so I don't know), but generally 2WD traction can be increased easily enough by simply shifting the transmission to a lower gear (From "D" to "2" or "2" to "1", etc.).

4WD is designed to provide additional traction whenever 2WD isn't sufficient. This can be when surfaces are slippery such as sand, mud, snow and ice or, when pulling a heavy load such as a trailer and tires are not gripping the surface well. Shifting from 2WD to 4WD High will provide more traction at the same tire speed. Maximum power from the engine does not come at low RPMs, so in order to get more pulling power from the engine with out increasing speed (or spinning tires), the transmission should shifted into a lower gear. This is especially helpful when pulling a trailer up a wet incline, etc. If 4WD High in 1st gear is still allowing tires to spin or not providing enough pulling power, then shifting the transfer case from 4WD High to 4WD Low will allow the engine speed to increase (providing more power) without increasing the speed of the wheels (reducing the chances of spinning tires).

4WD should never be used while operating on dry pavement. Since tires wear at different rates, and turning left or right slows the inside tire and speeds up the outside tire when compared to the rear tires, a certain amount of slip is required. Wet surfaces provide this necessary amount of slip - as does sand, mud, snow, ice, dirt, gravel, etc. You should take the time to see how each selection of High and Low affects engine speed and vehicle speed and how the surface and any trailer further changes traction. With a little experimentation, you'll see how it works and be able to choose the right range with little thought.

Don't forget to have the transfer case & front differential fluids checked and changed as per the manual. Neglecting this simple service intervals can leave you stranded when you need 4WD and can be very expensive to repair.

I hope this helps & good luck!

Tis a transfer case issue. Could be shifting fork wear pads worn out which will wear the fork ends to where their bent.

First, you do not need 4 low unless you're stuck out in the bush somewhere. Secondly, when you shift from 2 high to 4 high, it goes in immediately. To access 4 low, the tranny shifter must first be put into neutral, wait five seconds, then shift into 4 low. To shift out of 4 low back to 4 high, you must shift into neutral for 5 seconds again. They both flash at the same time because you have not shifted into neutral gear with the transmission.

this is a known issue with the gm 4L60E transmission. the valve body in transmission causes this. if it is wore, then less fluid is sent to shift selonoids. thus causing torque convertor not to lock up, and this causes slipping. if it slips 2 consecutive trips then the transmission detects this and should turn on check engine light. ( p1870 ). you can see if the tcc solinoid is bad. but if not its usually the valve body in tranny.

4wd auto: you can shift into this mode at anytime. it is good for conditions where you might need 4wd.
4wdhi:: you can shift into this at speeds up to 30mph and both of these back to 2wd while in gear.
4wd lo : stop vehicle and shift truck into nuetral ok to be rolling around 3mph shift into 4lo then put in gear same when shifting back to 2wd

make sure your 4WD switch is working.and fuse is okay.because your 4WD is control by 4 electric shift motors in which drive a rotary cam which moves the mode fork and range fork inside the transfer case to select between 2WD HIGH A4WD - 4WD HIGH AND 4WD LOW RANGE.a shift motor sensing plate on the shift motor monitors the range in which the transfer case is operating a transmission range sensor monitors the gear position of the transmission.which must be in neutral to shift into low.a pair of solenoids one for 2WD one for 4WD.mounted on the upper right firewall route vacuum to the vacuum motor which engages and disengages the center axle disconnect collar in the front axle assembly.a 4 x 4 shift motor relay module contains two GEM controlled relays which shift the transfer case shift motor between 2WD and 4WD modes.a solid state clutch relay activates the A4WDclutch inside the transfer case.

I had this exact problem on my 2005 5.3L Suburban... It would shift into 1 and 2 and reverse, but not 3 and 4.

I took it into a transmission shop, and he said the 3-4 shift solenoid was burned up. Wanted 1500 to fix it. Far from home, so I have to pay it.

Rebuild the transmission

Transfer cases can be quirky. I've got a 91 Wrangler, an 86 Cherokee and a 75 Blazer. When I go from 2WD to 4WD, they each have their own personality.

There are a number of things I've learned to persuade a stubborn xfer case to shift.

Try mixing these :

• Engine running, vehicle not moving
• Engine off, Shift Xfer case, Restart
  
• Tranny in neutral
  
• Shift Xfer case 'N', Tranny in gear, Tranny in neutral, Xfer case to 4HI or 4LOW (as long as you feel it register), Tranny in gear, try to move
  
• Shift Tranny to Reverse, roll a few yards
• Lock/Unlock the Hubs

To get back to 2WD:

• Drive for a few feet in a straight line
  
• Unlock the hubs
• Tranny Neutral
• Shift xfer case

Let me know how it turns out.
Mike