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4WD Actuator


mjtr21
02-06-2007, 09:32 PM
Does anyone know where I can buy the Vacuum Actuator for 4 Wheel Drive besides the car dealer. I went there yesterday and they wanted $97.26. I know I can probably find it somewhere else for a lower price. It would be also best if I didn't have to buy on the internet. Thanks in advance.

ZL1power69
02-07-2007, 12:27 AM
try a local junk yard.

laxman21
02-07-2007, 10:33 AM
try a local junk yard.


Got one there for $10.

MT-2500
02-07-2007, 12:11 PM
Does anyone know where I can buy the Vacuum Actuator for 4 Wheel Drive besides the car dealer. I went there yesterday and they wanted $97.26. I know I can probably find it somewhere else for a lower price. It would be also best if I didn't have to buy on the internet. Thanks in advance.

Dealer would only hurt one time.:grinyes:
But if you want to shop around as said bone yard or give your local parts places a call.
Some may have a after market setup on them.
Check this link.
http://www.automotiveforums.com/vbulletin/showthread.php?t=665179
Good luck and let us know how it goes.

herkyhawki
02-07-2007, 02:31 PM
Please read other threads first. http://www.automotiveforums.com/vbulletin/showthread.php?t=665179

Don't waste your time getting one from a junkyard, they just don't last that long.

Jeremy Fitch
02-07-2007, 11:14 PM
http://cgi.ebay.com/ebaymotors/Dorman-600-102-Front-Axle-Actuator-Vacuum-Chevy-GMC_W0QQcmdZViewItemQQcategoryZ33731QQihZ011QQitem Z320078910161QQtcZphoto

mjtr21
02-08-2007, 09:56 PM
Well I found an actuator at Napa for 52.00. I took out old one and replaced it with new one but still no 4WD. I can hear encoder motor working, TCCM under dash still clicks, switch on dash still works. the new actuator works because i started truck and put in 4WD and i reached under battery and i could feel that rubber part which was sucked in as far as it will go. (almost touched the coolant fan doing this haha) So i dont know what else to check for. When i put it in 4WD i can hear a wierd rubbing noise on the right front wheel too almost like it wants to engage. Maybe the shift cable to the front diff needs to be lubed. i will try that tomorrow but i dont know what else to check.

mjtr21
02-08-2007, 11:13 PM
i will try to check cable to front differential tomorrow but if its not that then i guess i will replace vacuum lines. on my truck there are three goin into vacuum switch. one goes to actuator under battery, one goes up to vacuum ball on hood and i dont know where thirs one goes. also where would i get these lines and how much? thanks.

blazes9395
02-08-2007, 11:20 PM
If your cable is getting pulled by the actuator when you press the 4x4 button inside the truck, then your getting vacuum to the actuaotor. Its not a vacuum problem. Your problem will then lie in the front, either the front differential itself, or the actuator, or related hardware.

mjtr21
02-09-2007, 02:52 PM
yeah i will check the differential cable in a little while because when i put it in 4WD i can hear a wierd rubbing/grinding noise almost like it wants to engage the front wheels. so i guess that cable isnt pulling enough. i really hope theres not something wrong with the front axle or something. thanks for the suggestion.

muddog321
02-10-2007, 06:27 AM
Looked at profile and 97 Jimmy so np233 case (3 button dash) so I would say look at the vac lines drivers side under hood then down to the 3 port switch on the transfer case. They are most common problem and a partial vac will cause that actuator to only partially pull/engage the front axle coupler.

mjtr21
02-10-2007, 08:44 AM
is that actuator diaphragm supposed to suck in all the way or it there supposed to be a little bit not sucked in? cause i bent my arm under the battery tray and i felt while truck was running and in $WD and it was suckin in but not completely. thanks for the suggestion. since tehre is 3 ports on the switch, i know one goes to the actuator and another goes up to the vacuum ball mounted on hood, but i dont know where the third one goes. i think i seen it ziptied onto the transmission filler tube. what is it for?

JaVeRo
02-10-2007, 09:45 AM
The third line tied to the Dipstick is the vent line. When you take it out of 4wd the vent line allows air in to release the vacuum on the actuator.

James

JaVeRo
02-10-2007, 10:18 AM
This is a pic of the part that the cable pulls. It is a clutch fork on a sleeve with splines inside that stays on the differential carrier until the cable pulls, then it mates up to the splines on the inner axle shaft engaging the front.
http://i48.photobucket.com/albums/f236/JaVeRo/100_0120.jpg
In the picture I have the clutch fork pulled with a hose clamp on the other side of the mounting plate to hold it in position until I get it bolted on.

If your cable is not pulling far enough due to corrosion, the sleeve may not be engaging the splines on the axle. If it has been run like that very much, the splines may be wore or broke.

James

blazes9395
02-10-2007, 10:31 AM
How are the front axles, specifically the CV joints on the axles. Have they been checked for proper operation? Sometimes the axles could break at the joint. If this happens, the front diff will not lock, and you will not have 4x4 operation. They look completely normal by looking at them on the outside, but the only real way to check them is to get the front up on jack stands(or a hoist) and turn both front wheels separately, while very closely watching the axle turn. The axle should turn smoothly, and in one piece, while the other wheel should slowly be trying to turn in the opposite direction.

A way to check the front axle manually is to disconnect the cable to the actuator, pull it and use some locking pliers to keet it pulled(engaged. If it now wroks, then the front diff is fine. If it doesn't, its a diff problem.

Good Luck

mjtr21
02-10-2007, 11:07 AM
my father took the truck somewhere so when he gets back i will try to manually pull the cable. should i pull it out as far as it will so and then lock the pliers? thanks a lot for your suggestions. if it works like that then i guess i will be changing vacuum lines out.

mjtr21
02-10-2007, 09:16 PM
well i tried the manual way and the 4WD still didnt kick in the front wheels. so im guessing its a problem with my front differential. man i was hoping it wouldnt be something like that. so what kind of part in the front axle will need to be replaced for it to work? unless the cable isnt pulling all the way at the differential end but i doubt it. so any suggestions?

JaVeRo
02-11-2007, 01:03 PM
I am thinking it is one of three things or a combination of three.

First would be not getting enough vacuum but you tried pulling the cable by hand and it would not engage so that's probably not it.

Second would be that the cable is corroded and third would be that the gear/sleeve in the picture I posted is worn.

Pull the battery out and remove the battery tray. disconnect the cable from the actuator and look at the way the clip is made and how it attaches because the clip on the other end is made the same way.

Crawl underneath the truck and where the other end of the cable attaches to the axle you will see a switch screwed into the side. Unplug the wiring connector and remove this switch. Now remove the three bolts holding the cable housing to the axle. There are no seals on this so if it's not the problem, you can put it back together without having to wait for parts.

Slide the cable housing back until you can release the clip and remove the cable. This is the reason for disconnecting at the actuator first, you wouldn't have enough slack to be able to slide the housing back. After you disconnect the cable, it should look like this:
http://i48.photobucket.com/albums/f236/JaVeRo/100_0123.jpg
Jack up the right front wheel. Pull on the stem shown in the picture while slowly turning the the wheel. If it engages the driveshaft will start turning. If you had the truck in 4wd before you removed the battery then the axle will lock and you won't be able to turn the wheel. This is good.

I am guessing that you will find the problem in the cable. If the axle does not lock when you pull the stem (the wheel spins but the driveshaft does not) then the problem may be the clutch fork or the sleeve that the fork rides on (see the picture in a previous post). That is not good but still possible to fix yourself, it will take a lot longer though.

If you find the problem and start putting things back together, put some sealant on the surface of the plate where the cable housing mounts with the three bolts. This will help keep dirt and water out of the cable. When you screw the switch back in keep in mind that the housing is plastic and don't over-tighten or you will be buying a new cable housing.

Let me know what you find.

James

mjtr21
02-12-2007, 04:59 PM
that is a better picture. i will go out in a few minutes and put the truck in the garage b/c its only 10 degrees out. then i will post my results. thanks very much.

mjtr21
02-12-2007, 06:45 PM
well i took off the cable and housing and jacked up the right front wheel. then i pulled out on that little stem part as far as it would go and turnd the wheel. i had it in 4WD and when i turned the wheel it DID turn and i could feel a small thumping on the little stem. so i know this means that thing on teh other side of that housing inside is worn. i think you called it a clutch fork or sleeve. is it hard to take it apart? and do you have the steps. thanks you very much.

JaVeRo
02-12-2007, 11:30 PM
The hard part is getting to it. You will have to pop one of the ball joints out and remove the axle from the hub. After you get the axle out of the hub you can remove the axle (the part with the two rubber boots and cv joints) with the inner axle shaft housing. There are two bolts holding the inner axle shaft housing to the frame and the last two of the five bolts at the differential. While you are doing this you should go ahead and replace the inner axle shaft seal and the clutch fork seal.

Pay close attention to the way the parts come out of the differential so you can put them back in the right order.

James

mjtr21
02-13-2007, 02:25 PM
how much would this cost to have my mechanic do it for me? i really hate ball joints and never had luck with them. also what is the name of the part i have to buy? thanks for your help.

MT-2500
02-13-2007, 02:37 PM
how much would this cost to have my mechanic do it for me? i really hate ball joints and never had luck with them. also what is the name of the part i have to buy? thanks for your help.

You need to talk to your repair shop about the cost.
Most of them will give you a estimate on the repair.
But on something like yours they may have to check it out and or take it apart to check it out.
Check out and tear down may run into 1 or up to 3 or4 hrs labor.

JaVeRo
02-14-2007, 10:17 AM
how much would this cost to have my mechanic do it for me? i really hate ball joints and never had luck with them. also what is the name of the part i have to buy? thanks for your help.

If you are not comfortable with replacing ball joints I highly recommend taking it to a mechanic.

According to the Helm manual pg 4-45 the parts that MAY be affected is (9) Clutch Gear, (12) Clutch sleeve, and (22) Fork. I recommend replacing the (3) Seal in the inner axle housing and the (20) Seal on the Clutch Fork. And check the inner axle shaft (4) Bearing while it is apart.

These numbers will be helpful if the parts diagram is the same as the one in the Helm manual. I think it is but I could be wrong, my wife says I usually am.

Keep in mind that this would be my next step in finding the problem. Yours could be deeper into the differential such as spider gears or several other problems.

James

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