4x4 doesnt work??

[76chevyman]

Ok i have a customer that bought me his suburban. That 4x4 doesnt work. Ive been the only one to touch this truck in 3 years
its a 95 chevy suburban k1500. I havent got under it yet. But by playing with the trnsfer shifter. ive ruled out the trnsfer case she is engaging. at the transfer, and the front driveshaft is still there LOL. So my only thought would be that swicth on the front diff. I thinks its a thermel swicth. would that keep the 4x4 from not working. because that the only thing to lock the front becasue theres no locking hubs. any inout would be great much thanks

Rich :burnout

[wyldman]

It is most likely the thermal actuator.

GM has an electric actuator out now,or you can go with a cable.

[digger242j]

Our 93 Chevy 2500 lost the 4 wheel drive in the middle of our last plowing session. After confirming that there was power to the front driveshaft and that the actuator was working, the shop took the front end apart. The mechanic wasn't sure he was calling it by the right name, but what he referred to as the "interaxle shaft" (about 5 inches long, with a splined end into the differential, and a gear end that's engaged by the actuator), had cleanly broken right in half. The end still in the differential looked like it might be a problem to remove, but it slid right out by just pulling on it with a magnet.

[urethane dino]

Far as I know all full size GMs from 88 on used an electric acutator. It threads in and out to replace and or install.
About 100.00 or so to replace.
Dino

[76chevyman]

Thanks for all your input guys i was 99% sure it was that thermal swicth. But i can also see the inner shaft going to but if that went i would be looking for noice. So i guess i will be replacing the thermal swicth. Call the dealer Monday. Or see if NAPA has it.

Rich:burnout

[capt.craig]

I picked up a boat for a friend once with my 95 S10. tried to get up the steep ramp no 4 wheel drive. Later I realized I had no head lights , Ended up that the fuse for the head lights also runs the 4 wheel drive. trailer wiring must have had a short in it. Just a thought.

[TJS]

Sounds like you need an actuator. I bet the chevy dealership will have them in stock and the parts guy should know what you want right away.
T.J.

[76chevyman]

Well i called the dealer today. THey said that i had to order a new wiring harness because the wiring was updated after that year. SO i said how much. He said with the wiring harness and acuator it was $230. Plus my time to sooilder the new wiring harness in. I said no thank you. NAPA had one that plugs right in for $85. Thanks for all your input guys. Ill let you know if it works

Rich:burnout

[John DiMartino]

Rich,I bought them from GM with the harness for under 100 bucks,shop cost. Somethign isnt right.i have bought abotu 7 of them. I liwk the updated ones they go in instantly ,no delay time waiting.

[76chevyman]

I thought that was a little high myself. Plus whats the need to put in a new wiring harness. They said i would have to splice and soilder in the new harness. That takes time to do when you want to pertect it from the weather. And to pay $100 plus just for the harness is unreal. and beleave it or not thats with my 30% discount.:confused: So i guess i will be going with NAPA on the acuator. That should just plug in to the stock harness.

Rich:burnout

[digger242j]

Bringing this thread back up again...

Same truck as I mentioned above, 93 k2500, and again there is no four wheel drive. I doubt it's the same problem as before, because this time the 4 wheel hasn't been used for quite a while. (The broken shaft I described above was the result of, shall we say, "excessive enthusiasm" on the part of the operator.) I found out it wasn't working now becasue I was spinning the rear wheels trying to move on wet grass, and when I engaged the 4 wheel it didn't help.

I haven't really taken too close a look at anything yet--I came to reasearch the problem here first.

The transfer case engages--it's very obvious when shifted into low range. The indicator light for the front axle does not illuminate when either 4 hi or 4 lo is engaged. The 25 amp fuse in the space marked "25 4WD", is good.

I'd suspect the actuator immediately (even though it was replaced 2 years ago), except for the fact that the indicator light does not illuminate either. Should I suspect a bad switch, or connection, or does the illumination of the light depend on the actuator functioning properly? If it is a switch, where is it located?

[Alan]

The indicator for the front wheels won't light unless the front axle lock is engaged. That engagement is accomplished by the infamous Thermal Linear Actuator. The TLA failures I've seen were usually over a period of time but there's no reason one couldn't go south instantly.

Somebody has their head up their butt on that upgraded actuator. We changed the one in our 89 1500 to the new version, no problem and the new wiring harness is plug and play, no soldering or anything. Cost wasn't much more than the old TLA, which was in the neighborhood of $75.

The newer actuator won't work in early (88 at least) 3500 Series with the 9.25" ring gear.

[digger242j]

So, it could still be either a wiring problem or the actuator itself?

I'll have to check with the garage and see whether they made the mod when they replaced it. (Now that I think of it, that was 3 years ago.) I wasn't driving it that time either, but I understood the symptom at that time was a grinding noise coming from the front axle.

Thanks for the speedy reply. :)

[76chevyman]

On that suburban i found it was the wiring it got tangled around were the shift linkage is for the tranny it was two wires that pluged in on top of the transfer case. I soildered and heat shrank the wires and haven't had a problem sence. It was the wires for the acuator for the front diff i just traced them back to the TC. i think it was two or three wires.

Rich :burnout