# Four wheel drive?



## milwaukeevtwin (Nov 2, 2008)

1989 GMC 2500 When it put it in four wheel drive it acts like the front tires are not working? The rear just spin and i get no traction out of the front. When i put it in low the tranny just gears down. Same thing. It does not even grab when you turn a corner. Transfer case? Any ideals?


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## Duncan90si (Feb 16, 2007)

Check the 4WD fuse. It could also be the thermal switch thats on the front diff.


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## milwaukeevtwin (Nov 2, 2008)

Duncan90si;896391 said:


> Check the 4WD fuse. It could also be the thermal switch thats on the front diff.


I hope it is the fuse. I WILL TRY LATER.THANKS


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## 2COR517 (Oct 23, 2008)

Those thermal actuators can go without warning. Napa usually stocks them, but this is the real solution..

http://www.4x4posi-lok.com/app_chevy-k.html


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## JohnnyU (Nov 21, 2002)

My actuator died on me in the middle of a blizzard three years ago. Thanks to a very knowledgable and experienced mechanic out of Michigan, I was back on the road 10 minutes later. His solution was to install a regular lug nut (about 1" long) before the actuator. Basically, since the actuator didn't work, this would lock the axle so that I would still have 4wd. It is similar in principle to leaving your external lock-out hubs locked in and just shifting the transfer case.

The _real_ fix was when I cut all the IFS garbage out and installed a high-pinion Dana 60.


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## 2COR517 (Oct 23, 2008)

I actually did some "creative repairs" on mine last nine. I used a 7/8 socket. Fit perfectly.


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## JCI Trans (Oct 21, 2008)

Its a very common problem, as stated above the best fix is the 4x4 posilock.


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## tuna (Nov 2, 2002)

I`ve done the lugnut trick a few times works great,BTW I left it that way for 4 years no problem.


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## milwaukeevtwin (Nov 2, 2008)

*truck*



milwaukeevtwin;896443 said:


> I hope it is the fuse. I WILL TRY LATER.THANKS


Well it was not the fuse. Thanks, For the help guys.


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## JohnnyU (Nov 21, 2002)

It's seldom if ever the fuse. It's either the actuator, as I've already described, or the switch on the transfer case itself. I'm willing to bet its the actuator.


To test this, unscrew it from the axle housing, engage the 4wd and wait to see if it extends. This may take a minute ot two as it is thermally driven. If this does not work, check to make sure that you receive 12V at the actuator plug. If you see 12V, then the actuator is bad. If you don't see 12V, then the switch at the tcase or wiring in between is at fault.


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## milwaukeevtwin (Nov 2, 2008)

*truck*

Well i took it to the trans shop. I just do not have time. We are still playing catch up with that truck down. Thanks for all the help. We will see what he says.
Thanks, Ron


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## JohnnyU (Nov 21, 2002)

Where are you located Ron? If you were close I would have gladly looked at it for you, but you're probably up around Chicago.


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## milwaukeevtwin (Nov 2, 2008)

JohnnyU;898999 said:


> Where are you located Ron? If you were close I would have gladly looked at it for you, but you're probably up around Chicago.


I really appreciate that. I live in South Beloit.This is my first year plowing for my self and i have had all kinds of problems. Oh well that is part of the business.
Thanks, Ron


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## CAT 245ME (Sep 10, 2006)

Does any one know what is the life span of these actuators? Are they all the same for 88-98 trucks?


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## JohnnyU (Nov 21, 2002)

The lifespan is indeterminable, but can be anything from a couple years to a couple decades. 

There was a change in 96-ish era when GM upgraded to a fully electric unit. Posi-lock is available for a similar price to doing to upgrade on an older truck.


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## bad93blaster (Dec 25, 2008)

2COR517;896456 said:


> Those thermal actuators can go without warning. Napa usually stocks them, but this is the real solution..
> 
> http://www.4x4posi-lok.com/app_chevy-k.html


those work i have one in my old 1ton. i was blowing actuators on the 2nd 3rd time putting in 4 wheel drive ( cheaper for posi-lok then tring to figure it out)

i have also used a cut down 1/4" bolt in the middle of the night


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## M.S.P.M. (Nov 2, 2009)

I have a similar problem but my 4 wheel drive wont engage at all. Its a 98 and it has the electronic push button system. It was just working this morning. Any help would be greatly apprecaited?


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## 2COR517 (Oct 23, 2008)

M.S.P.M.;901526 said:


> I have a similar problem but my 4 wheel drive wont engage at all. Its a 98 and it has the electronic push button system. It was just working this morning. Any help would be greatly apprecaited?


Can you still hear the transfer case shifting?


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## Duncan90si (Feb 16, 2007)

2COR517;901622 said:


> Can you still hear the transfer case shifting?


Along with what he said, try putting it in low range. Does it go into low range and is still in 2WD? Or does it do nothing?


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## M.S.P.M. (Nov 2, 2009)

I can hear a clicking i dont think its the transfer case. Since its electronic I was thinking mabye a selanoid. But I tried low range and that did not work either.


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## 2COR517 (Oct 23, 2008)

What do the lights on the buttons do? Have you used low range before? You need to put the trans in neutral to shift the case into low range. What does it do when you try to get into low range?

Can you get someone to push the buttons while you get under the truck and listen to the encoding motor? The encoding motor is what shifts the transfer case.


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## M.S.P.M. (Nov 2, 2009)

The lights on the buttons will flash on either the 4 wheel hi or low depending on which one I use, but then they go back to the 2 wheel drive. I have used low. I have had it nuetral when trying to shift to low and it just flashes then goes back to 2 wheel drive. We tried listening to it and it just clicks once when you hit the button but it never shifts.


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## 2COR517 (Oct 23, 2008)

Sounds like the transfer case shift/encoding motor is done to me. I think it can be confirmed with a scanner......


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## M.S.P.M. (Nov 2, 2009)

Ok thanks I will see if i can get it scaned.


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## 2COR517 (Oct 23, 2008)

You need a scanner, not just a code reader. Something will show what signals are coming/going from both the dash button and the encoding motor. Most of the cheap code readers just pull P engine codes, no drivetrain codes. I would try a transmission shop, or a dealer...


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## Duncan90si (Feb 16, 2007)

2COR517;902087 said:


> Sounds like the transfer case shift/encoding motor is done to me. I think it can be confirmed with a scanner......


.............x2


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## M.S.P.M. (Nov 2, 2009)

yeah i had it scanned and it was the encoding motor. Thanks for the help.


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## 2COR517 (Oct 23, 2008)

Thanks for the update. It helps others with similar problems too.


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## milwaukeevtwin (Nov 2, 2008)

*4-wheel drive*

Well it turned out to be an actuator. Also when the last guy tore out the 700r and installed a 400 turbo, He tore the wires all apart and they had to be fixed from the fire wall. It was not a cheap fix, but it will earn it's keep the next snowfall. I picked up a solid body two wheel drive 93 with 43,000 original miles, that is going to be put on the 89 frame next year. I can not wait to get it done. it should be a real nice truck when i get done. I know it is going to be a lot of work, but the truck was given to me form my dad and i want to restore it.Thanks, Guy's


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## M.S.P.M. (Nov 2, 2009)

I had a friend fix it for me and napa has sent them parts that were not functioning properly so now napa is paying for the parts and labor. they are throwing in a bunch of free parts for my inconveince.


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## D&S snowplowing (Dec 8, 2009)

with the GM trucks its normally the acutator i had a 1990 same thing happened and after talking with people same thing happened


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