blazer 4ed problems transfer case?

[gottabethe3]

I was asked by a coworker if i would put in a transfer case in a 97 blazer for his mom. his brother had it all tore apart when I got it so i dont know what it drove like before. He said 2wd worked fine but no 4wd. I put the case in and it drives smoothly in 2wd but in 4wd on road is drive ok but it kind of a vibration but more of a shiver. I dont think this is normal but being it is in 4wd maybe? could the actuator maybe be not engaging all the way. One more thing after getting it going sometime when i put it in forward or reverse it takes off hard like i have my foot on the brake and the gas. then it lets loose. It did sit in a garage apart since last fall. so I am thinking it is just sticking brake calipers or cylandars or maybe related to first problem? any help would be great thanks.

[old_master]

3 button system or 4 button?
Are all 4 tires the same make and size?
Are all 4 tires worn evenly?
Is tire pressure equal in all 4?
4WD should never be used on dry pavement. It can cause a vibration like you mentioned, which can also lead to self destruction of the transfer case

With the engine at idle, transmission in park/neutral: In 2WD there should not be any vacuum at the front axle actuator under the battery tray. In 4WD manifold vacuum must be present. When you select 2WD, vacuum should drop immediately back to zero.

[gottabethe3]

3 button system or 4 button? 3 button
Are all 4 tires the same make and size? yes
Are all 4 tires worn evenly? close
Is tire pressure equal in all 4? yes
4WD should never be used on dry pavement. It can cause a vibration like you mentioned, which can also lead to self destruction of the transfer case

With the engine at idle, transmission in park/neutral: In 2WD there should not be any vacuum at the front axle actuator under the battery tray. In 4WD manifold vacuum must be present. When you select 2WD, vacuum should drop immediately back to zero. it does do this but i noticed that the diaphram appears to be sucking in fully but the cable appears to only be pulling about an 1/8" maybe a little more. i read somewhere it is supposed to move 1/2-3/4". is this true? what would this do if it was only pulling the cable part way out. would this the reason the transfer case to go bad in the first place?

[old_master]

The cable should pull in about 1/2". There might be a problem with the axle clutch or its linkage, inside the right front axle tube. Parts 9 through 23 all have to do with axle engagement. Any problems with any of these parts will not trash the transfer case. I suppose it's possible the actuator could be weak, or insufficient vacuum to it, should have manifold vacuum in 4WD. Parts 9, 12 & 23 will be damaged, (possibly more stuff) if the clutch doesn't fully engage. What was the problem inside the transfer case? Chain broke? Bearings toasted?




From your description, the brakes might be binding. Very common for the caliper guide pins to seize in the caliper brackets.... especially if it's been sitting for a while.

[gottabethe3]

Could it be that the cable could be getting crusty or dirty in side the sleeve and holding it up?

[old_master]

That's a possibility, what you might try is disconnect the cable from the actuator and manually pull the cable. You'll probably have to raise the right front wheel off the ground and rotate it to allow the clutch to fully engage. When it engages, you won't be able to turn the wheel. Notice how far the cable moves when the clutch engages, compared to how far it moves on its own when 4WD is selected.

[gottabethe3]

I want to start by saying thank for your help. I donot have the truck right now and cannot check the cable yet but will try to get it again to do this. When I do I will post my findings. Thanks again.

[j cAT]

Originally Posted by gottabethe3

I want to start by saying thank for your help. I donot have the truck right now and cannot check the cable yet but will try to get it again to do this. When I do I will post my findings. Thanks again.

as these age the vib in 4wd is normal. especially on dry pavement. tires not rotated does add to this vib.

then you have the drive axles and the cv/ujoints that will also add vibs.

with a 1997 you can't be too picky. check that the drive axles are straight and the joints are not worn.