No 4wd

[sub6291]

Hi guys, first snow today and 4wd will not engage. I hear a "weak" clunk when pressing the button, but lamp wont stop flashing. I can get it in low, but no 4wd there either. Where do I start? What you guys think?
Btw, its the -96 sub Im talking about..

Trond

 

[Big T]

I've shared your pain. Do you have the stock actuator for locking the front axle? GM changed from the thermo actuator to a motorized actuator in the '97 or '98 model year. The thermo actuator was prone to failure. The motorized is much better, but not foolproof. You will need the actuator plus a wire harness to make it work. You'll pay through the nose to get these from the GM stealership. There are cheaper sources on ebay or maybe RockAuto.

Here's a thread on this on another site:

http://www.chevytalk.org/fusionbb/showtopic.php?tid/205681/post/1594396/hl//fromsearch/1/#1594396

And another of mine:
http://www.chevytalk.org/fusionbb/showtopic.php?tid/207294/post/1606141/hl//fromsearch/1/#1606141

And yet another:
http://www.chevytalk.org/fusionbb/showtopic.php?tid/217617/post/1704253/hl//fromsearch/1/#1704253

All was well for quite awhile, until two weeks ago I had issues with it not going into 4wd. I seemed to have resolved it, but can't tell you what I did. Lost it for the 2nd half of a 1K mile road trip.

Steve

 

[trouttrooper]

x2 on front actuator. If you can get the low range then there's nothing wrong with your transfer case, the problem is in the front end. 99.99999% of the time it's the actuator or the wire harness going to it.

 

[woodchuck2]

X3 on the actuator. Check the connections too.

 

[sub6291]

Thanks guys, had a look at it last night and everything works perfekt exept the actuator. I have to get the upgraded version big T was talking about. Ive heard som rumors bout the price here in Norway, over 500$. Maybe you guys can tell me where to buy, also need the wiring.

Trond

 

[Big T]

Thanks guys, had a look at it last night and everything works perfekt exept the actuator. I have to get the upgraded version big T was talking about. Ive heard som rumors bout the price here in Norway, over 500$. Maybe you guys can tell me where to buy, also need the wiring.

Trond

Trond, I made the mistake of buying mine from the GM Dealership at a cost of $300 for the actuator and wiring harness. I would buy it off ebay motors. Here's an ebay buy it now listing for the actuator at US$76.95 and the seller has a 99.8% positive rating:

http://cgi.ebay.com/ebaymotors/1997...r_Truck_Parts_Accessories?hash=item19b6cbb08e

Here's the wiring harness you'll need for US$39.95 and the seller has a 99.6% positive rating:

http://cgi.ebay.com/ebaymotors/95-9...r_Truck_Parts_Accessories?hash=item56360d30c4

Those are the parts you'll need for this and you're done for US$117 plus shipping. Once you get them, the threads I posted have instructions on the installation. It's not that difficult, though the splicing suggestion under the transfer case shift was tricky for me. It's really a 30 minute job. If you should have any problems, post up here and we'll coach you through it. Good luck.

Steve

 

[sub6291]

Thanks for your help, Big T. Have to look into it real soon, winter is here.

Trond

 

[Big T]

Trond as for the connection of the brown wire in the replacement wiring harness, ignore the advice in the thread links I posted where they suggest splicing into the brown wire running alongside the transmission tunnel inside the cabin. I did this and it was a nightmare. Another suggestion is to tap into the brown wire where it meets a plug a the engine firewall just behind the fuel filter. After having the brown wire alongside the transmission tunnel go dead without explanation, I moved this splice as described. I traced the brown wire from the transfer case switch to this plug. Tested it and it was hot on the engine side of the plug. I peeled back some insulation and tested it with the brown wire of the harness and the actuator worked. I finished it off with a splice connector and some electrical tape. This position is way out of harms way from moisture getting on it. I did some offroading with it the other day and it worked flawlessly. Fingers are crossed that this will be a lasting solution.

Steve

 

[sub6291]

Thanks for the advice. Had some luck, got the chance to buy a new one for 120 bucks. Its the old style, not the improved type. Do not have to do anything with the wiring, then. Hopefully I can have a look at it this weekend, but the whole family is down with the flu so I`ll have to see.

Trond

 

[Big T]

Trond, if you bought the old style thermo actuator, I can guarantee you will be revisiting this again. I went through three of those and they go out at the worst possible time. Follow my advice on the wiring and it's a piece of cake.

 

[trouttrooper]

x2, do not buy the old style. you might as well flush that money down the toilet.

 

[ak diesel driver]

mines lasted 219000 miles. But I don't drive around in 4wd all the time either. Most people pull it into 4wd at the slightest indication of bad weather and leave it. That's why their frontends and tcases are worn out too. IMO driving at hiway speeds in 4wd is more dangerous. Need to buy good tires and slow down. I see people all the time pull it into 4wd and then speed up cause "I'm in 4wd"

 

[Big T]

mines lasted 219000 miles. But I don't drive around in 4wd all the time either. Most people pull it into 4wd at the slightest indication of bad weather and leave it. That's why their frontends and tcases are worn out too. IMO driving at hiway speeds in 4wd is more dangerous. Need to buy good tires and slow down. I see people all the time pull it into 4wd and then speed up cause "I'm in 4wd"

My thermo coupler failure history:

1) Logging road from Willitts to Ft. Brag. Come over a swale only to find a rutted mud bog ahead with too much speed. Can't stop on the slimey mude over hard pack, so I mash it only to end up on the far side, high centered on the rear axle and the thermo actuator failed on the front. Had to get yanked out by a tow truck for $300.

2) Last year in Big Bear Lake, epic snow season for local mountains. Thinking I have 4wd only to get stuck in some pretty lame spot for a 4wd. Thermo actuator failed.

Now I'm using the motorized actuator. Now that the wiring has been resolved after being lead astray by advice on another site, all is good.

 

[sub6291]

mines lasted 219000 miles. But I don't drive around in 4wd all the time either. Most people pull it into 4wd at the slightest indication of bad weather and leave it. That's why their frontends and tcases are worn out too. IMO driving at hiway speeds in 4wd is more dangerous. Need to buy good tires and slow down. I see people all the time pull it into 4wd and then speed up cause "I'm in 4wd"

Yeah, had the feelin I was doing the wrong thing, but when I use the 4wd its always on snow/ice so I`ll give it a try. But I think BigT is right about revisiting this again.

Trond

 

[ak diesel driver]

When I talk to tow truck drivers they say the #1 vehicles they pull out of the ditches are short coupled 4x4s. They don't have snow tires and are driving in 4wd. And driving too fast because they're in 4wd. I been on roads that were so slick you couldn't hardly stand up on them. 2" of ice with about 1/4" of water on them. Studs are a necessity then. I'm kinda lax on my summer tires but my winter tires are primo. Even had some double studded and siped.

 

[sub6291]

My tires, do not have to engage 4x4 every day with these. Very nice tires, Cooper in 265 dimension.

Trond

 

[ak diesel driver]

Same tires I'm running now.

 

[Big T]

AK I realize you got it on just about all of in terms of low temps, but even here in Sunny SoCal we get some snow. This was from last December up in the San Bernadino Mountains (Big Bear Lake). Nice dump of snow and I was stuck up at our place for a week.

Believe me, it was no fun driving in this stuff. I lost 4wd and was lucky I had BFG All Terrains, but still needed chains. It isn't me I worry about driving in this stuff; it's all the other kooks. As you can see the dogs have 4wd all the time and love to use it.

Steve

 

[ak diesel driver]

That's just a heavy snowfall for us. I can remember getting 48"s in about 36 hours once. The snow we get here is generally really light fluffy and dry. My Dad had a 76 Dodge clubcab powerwagon and with chains on the front when we were driving down the roads, just guessing where they were by the old snowbanks, wipers had to clear a steady 1" layer as snow was over the hood. Pretty rare though. I know what you mean about kooks though I won't let my wife out on the roads till they've been cleared for awhile.

 

[trouttrooper]

3rd week of March a few years ago we got 7 feet in 6 days in my old backcountry patrol area. Really wet heavy snow too. I was overwhelmed at day 3. Highway dept. came over with their big front end loader chained up to help clean me out....it got stuck. They managed to get it free and finished cleaning my driveway. A month later it was almost all melted off. I definitely don't miss the ridiculous snowstorms I had to deal with there.