4 Wheel Drive Problem

[TruckBoss223]

Hey guy sorry been crazy busy with work since its summer, I work on the beach and Hurricane Sandy destroyed everything. But with that being said I am having and odd problem i noticed yesterday. Ill try to explain it the best i can.

98 Chevy Tahoe 2dr. 5.7 NP246 Push button 4x4 switch 4L60E transmission.

I work on the beach all day and use my personal truck most of the time. Truck is running on 285/65 R16 DC MUD Countries. On the beach I bring them down to about 10-15 pounds no problem.

Driving on the sand is no problem at all. I have climbed over hills, super lose sand, wet sand whatever it doesnt even hesitate. Stopped on beach yesterday went to back up in 4 wheel HI and rear tires just DUG into ground. Put it in drive and pull myself out no problem. Only problem was i was parked to close to something in front of me so i could go forward. Put it back in reverse same thing rear tires just dug in front tires didnt even move. Put the truck in neutral switched to 4 Wheel LO pulled forward no problem, put in reverse and backed up no problem and right out.

Now my question here is why ? Is there something with the way the front end locks or do i have a problem. why does it 4x4 in reverse only work in Low. Everything drivetrain wise is still stock. What am i missing here and i have a feeling its very stupid answer.

Thanks for your help once again and as soon as the summer ends I will post some pics of mods i hope to complete. Just finished off my doubledin swap and the 05 console swap. Just gotta button some things up

 

[Donnie Yukonie]

Let me see if I understand you right , so is your tuck coming out of 4wd? or does it only work in reverse?

 

[mfdrookie516]

I understood him to say that when in reverse, the front wheels were only locking in when he went in 4x4 low, but wouldn't in 4x4 high?

 

[TruckBoss223]

Correct . No 4x4 IN REVERSE in HIGH only when in low. Forward works fine in all modes.

 

[SunlitComet]

As the 4hi in reverse selected manually and yo got a solid indicator showing the front axle locked or was this in Auto 4wd mode?

 

[TruckBoss223]

In 4 Wheel High. Drove on beach in 4H no problems like i was on pavement, put truck in park, left it running, got out for a few and then put in reverse to back up and pull away and the back tires just dug all the way. Put in foward pulled myself out. eventually tried LO and not single problem

 

[SunlitComet]

Ok just to make sure i get this right when you are in 4hi and reverse, no front wheel power engagement on pavement and sand? but forward is fine and 4lo has no issues at all correct?

 

[saif najd]

In 4 Wheel High. Drove on beach in 4H no problems like i was on pavement, put truck in park, left it running, got out for a few and then put in reverse to back up and pull away and the back tires just dug all the way. Put in foward pulled myself out. eventually tried LO and not single problem

Ok! I have almost the same today happened to me the same I have a tahoe 98 4wd buttons!

I was trying to park it on higher ground without slipping tairs it did not engage the front wheels only rear!

And when I try to make a hard tirn on 4H I feel like something is jamed (driving forward! )

Please try to do hard turns without flooring the gas paddle

 

[TruckBoss223]

Yea it's weird. 4 wheel high in reverse no front engagement. Everything else is fine.

Sent from my DROID RAZR HD using Tapatalk 4 Beta

---------- Post added at 04:20 AM ---------- Previous post was at 03:02 AM ----------

Ok just to make sure i get this right when you are in 4hi and reverse, no front wheel power engagement on pavement and sand? but forward is fine and 4lo has no issues at all correct?

I cant really tell on pavement The front tires jump and bind a little on pavement but i can not tell if there is power to them. POSITIVE nothing in reverse. Going to throw it on a lift sometime this week and see what happens

 

[SunlitComet]

This makes it sound like and electronic lock out of some sorts. Maybe as not to overstress the tranny. Only one rear gear ratio in the tranny so to play it safe put the tcase in low. There are no sprags in the tcase or front axles that will do this. I have eliminated the speed sensors and the shift motor(actually still thinking this part out some more) and clutch pack and the TCCM has and does communicate with the pcm over the serial bus. Will keep looking into it.