1998 Blazer 4X4 shifting problem

1998 chevy s-10 blazer LS 4X4

The transmission has been working perfect, no slipping, hard shifting or late shifting or anything.
now suddenly, when leaving a parking lot it will only shift once.
apparently it can only access 2 gears now but I`m not sure which 2, it has a 4 speed transmission.

I manually put it into to 1st and it runs fine, then I manually put it into 2nd and it runs fine,then I manually put it into 3rd and at about 20 MPH it felt like it shifted.
I checked the transmission fluid and it is full and nice and red.

in drive it only shifts once at about 1,500 rpms when it shifts the rpms jump to about 2,000 and then drop back down to 1,500 after it shifts.
at 3,000 rpms it is only going about 30 MPH and doesn`t shift again.

one last odd thing when I turn the wheels all the way to the left or the right and try to drive the vehicle kind of chugs, as in it will move then stop, move then stop in quick succession.maybe with the wheels turned all the way in either direction it is creating resistance and causing the transmission to slip?

I checked the codes and the only 2 codes it was showing was:

po147: O2 sensor heater bank 1 sensor

and

po446: Evap emission control system vent circuit malfunction

I cleared the codes and test drove it but the shifting problem was still present and the codes didn`t return.


could either one of those codes cause the transmission to suddenly not shift correctly?
is there a fuse or a relay for the shift selenoids that might have gone bad?

I`m going to check all the fuses tomorrow,i`m just wondering what else I should check?

it`s never shown any signs of a transmission problem.

a reply to: Tardacus

Not sure about yours but I had a heck of a time with a older GM with a lock up converter that was being wankie ...just a thought

a reply to: Tardacus

Have you tried engaging the 4WD and then ensuring it is disengaged?

It sounds like 4 wheel drive is engaged

You absolutely are in four wheel drive. Furthermore you may have it in low 4 WD. I have a 98 Z71 and that's what it does if you put it in 4wd low lock and turn on a dry surface. Plus in Low, it will only do about 30-35 MPH tops

originally posted by: Snarl
a reply to: Tardacus

Have you tried engaging the 4WD and then ensuring it is disengaged?

I thought of that too,but when I tried to engage it nothing happened, the lights on the 4 wheel drive buttons don`t work, so I wasn`t sure if I was trying to engage it correctly.
I assume that when you turn the vehicle off it automatically disengages the 4 wheel drive but I`ll try again tomorrow and I`ll check the fuse for the 4 wheel drive.

originally posted by: visitedbythem
You absolutely are in four wheel drive. Furthermore you may have it in low 4 WD. I have a 98 Z71 and that's what it does if you put it in 4wd low lock and turn on a dry surface.

thank you!

I`ll definiately check that first thing tomorrow, because when I tried to engage the 4 WD I didn`t hear the TCCM click nor did I hear the 4 WD engage, so already being in 4 WD would explain why it won`t go into 4 WD.

I wasn`t driving it when it happened my daughter was, maybe she accidently pushed the 4 WD button which is located directly above the radio.

originally posted by: Tardacus

originally posted by: Snarl
a reply to: Tardacus

Have you tried engaging the 4WD and then ensuring it is disengaged?

I thought of that too,but when I tried to engage it nothing happened, the lights on the 4 wheel drive buttons don`t work, so I wasn`t sure if I was trying to engage it correctly.
I assume that when you turn the vehicle off it automatically disengages the 4 wheel drive but I`ll try again tomorrow and I`ll check the fuse for the 4 wheel drive.

I think 98s disengage on the fly. They certainly go into 4 wheel drive on the fly. Some of the older chevys, you had to back up about 10 feet

a reply to: Tardacus Push that 4wd button again and drive in a circle to check it. Thats probably all it is

Is it a floor shift or push button (im assuming push button)? Either way it will not disengage on its own. Check the fuse because that might be why the lights are not working. If the fuse is blown then you could either have a short or the push button control (just a possibility not saying it is bad)could be bad (there is some other possibilities of other things being bad but that would be my first guess is the push button control). Make sure the vehicle is in neutral while shifting in or out of 4 wheel drive.

a reply to: visitedbythem

I`m going to pull the fuse for the 4 WD tomorrow to see what happens, maybe it`s stuck in 4 WD and pulling the fuse will disengage it.

the lights on the 4 wheel drive buttons have never worked since she bought it 10 months ago, and the fuse was burned out when she bought it. I replaced the fuse and the 4 WD did work when I tested it even though the lights on the buttons don`t work.

a reply to: spartanwarrior

it`s a push button 4 wd, I only tested it once after my daughter bought it and replaced the burned fuse and you can definitely tell when it goes into 4 WD. you can hear the TCCM clicking and you can hear and feel the axles engaging, but today when I tried to engage the 4 WD I didn`t hear or feel anything, so it may already be in 4 WD.

a reply to: visitedbythem

It probably is able to shift on the fly but ive never liked shifting on the fly unless i had to.

a reply to: Tardacus

Thats definately where i would start is with the fuse then. Keep us updated, ill help the best i can if more issues arise.

originally posted by: spartanwarrior
a reply to: visitedbythem

It probably is able to shift on the fly but ive never liked shifting on the fly unless i had to.

Ive shifted into 4WD doing about 35. Its when you go back into 2 WD that it can grind a little. I just usually do it at a stop. Mine is a manual shifter with and automatic tranny

a reply to: spartanwarrior

thanks

I`ve only had one 4 wheel drive and it was a jeep with a manual 4 wheel drive shifter on the floor it was easy to know when it was in 4 wheel and when it wasn`t.
with these push buttons anything could go wrong and you wouldn`t know if it disengaged or not.

I`m old school,when I saw the push buttons for the 4 wheel drive the first thing I thought was, if your`re too lazy or incapable of moving a floor shifter for 4 wheel drive why are you even buying a 4 wheel drive?
I know why the car companies make them like that, so they can make more money fixing them when they break
do we really need a computer module to shift into 4 wheel drive when a floor shifter worked just fine for so many years?

the fewer electronic parts and moving parts, the better,less things to break.

a reply to: Tardacus


The shift actuator on the transfer case could be bad / or stuck in 4 wheel low if it feels like it's lurching when you have the wheels turned all the way right or left. Without it running climb under and listen for it to shift
while the key is turned on while someone hits the switch. If the fuse was bad it should just default back to 2W HI and you would not get 4W HI/LOW.

There should be an indicator switch on the front axle that turns on the dash lights to tell you it's in 4WD, check the switch, plug and wires, they may be bad or just have a bad connection. The switch does not control the 4WD, it just turns the lights on.

How about the ol disconnect the battery for 1/2 hour or so, and reconnect, may reboot the computer, if that was the problem.
Or call SCOTTY KILmer......he would know how TO FIX, YOUR CAR!!!.

With that kind of system you WANT to be on the fly a little when shifting from 2W to 4H. It has centrifugal force Lockout Hubs that only engage, or dis-engage when doing 5+ miles an hour.. Don't be afraid of popping the 4H doing 30 in that model. Now, from 4H to 4L you will want to be stopped to activate the Neutral between... you don't worry about the Hub locking then because the hubs have already locked in 4H. If you turn a circle and she bucks like a bronco, your in 4WD, or your lockouts did not disengage - they need some motion to work.

a reply to: Tardacus

Those two codes have to do with a probable bad oxygen sensor and maybe what is a gas cap that is not sealing well. If you can figure out the 4wd problem and get it out on the open road, they may return.