I'm trying to fix a wreck I bought last week and I'm having some trouble. many vacuum lines where severed during the wreck or where ripped out by someone.

I hooked the differential vacuum actuator direct to a vacuum line because I can't find a valve to hook it too and it differential works fine.

On my transfercase there is a connection that has 3 tubes that connect to 3 lines, one goes to the top of the transfer case and I have no idea where the other two lines go.

Can anyone give me an idea?

The Jimmy is a 1993 slt with a 4.3 liter vortec 8th vin number is a "W"

I picked up a haynes book on this but it doesn't have much in there and what is does have doesn't resemble what I have.

Thanks
Sam

After looking around on the web, I assume the vacuum connection to from the xfer case is thus.

1 line goes directly to a vacuum storage bottle and the other must go to the vacuum actuator that engages the front differential.

The vacuum resevour is missing on my truck.

I'm tired of chasing issues on the beast and ordered a jimmy shop manual.

One hose is vacuum supply to the t-case and comes via a tee fitting near the back side of the intake manifold next to the distriburator on the passengers side. The other leg of the tee fitting goes to the vacuum ball, and to the dash hvac controls (center of firewall).

One hose is a vent hose and it has a tee fitting which connects to teh back side of the t-case, then runs up into the engine compartment next to or under the battery tray. It will have a filter on the end of the hose.

The third hose provides vacuum to the front axle accuator. It also runs up into the engine compartment and under the battery tray, except it terminates at the vacuum actuator.

All three hoses run up over the tranny and are held to the top tranny bellhousing bolt on the passengers side via a clamp/bracket. Same bolt also holds the tranny dipstick tube in place.

Those are the three hoses. The rest of the vacuum system should be outlined on a sticker somewhere under the hood.

You can eliminate the vacuum hoses with a Posi-Lok kit. Plug them off at the t-case. You will still need the vent hose. You can buy the kit, or make your own for less then $50. Or run the hoses and deal with the vacuum system.

Thank you for the information. The fan shroud is also missing on my truck. Someone ran it into a tree and half the dog house was removed along with the original radiator. Luckily for me the only damage the engine suffered was a broken water pump which I replaced.

From what you've said above the t-case doesn't need the vacuum line to shift, it only uses it to control the front differential. If that is the case I must have an electrical issue to track down because my case won't engage.

Before I go any further, I'm going to hook up everything like it was and see if it works.

http://www.forestryforum.com/gallery/albums/userpics/13024/JIMMY1.jpg
Sorry I don't know how to post pics here. This is a link to a reduced size photo of my jimmy showing half the dog house gone. Notice my ford f150 radiator on there for test purposes.

http://www.forestryforum.com/gallery/albums/userpics/13024/JIMMY4.jpg

I didn't want to bypass the oil cooler or tranny cooler so I salvaged some of the original radiator.

http://www.forestryforum.com/gallery/albums/userpics/13024/JIMMY3.jpg
I have no idea what this hooks to.

http://www.forestryforum.com/gallery/albums/userpics/13024/JIMMY2.jpg
I didn't know where this went ether, finally figured it was the connector for the AC compressor clutch. Who needs AC anyway.

Sorry about the small size of the photos, some folks I know like the small size due to bandwidth problems.

Thanks
Sam

Being a '93 no doubt you have the push button switch. Test it. Cehck the wireing connections to the t-case. Next to teh vacuum plug is the electronic t-case actualtor. verify its getting power, could be a blown fuse, could be a broken wire.

You can engage 4hi on the fly, 4lo must be engaged with the tranny in nuetral or park and going less then 5mph.

and your postive that front driveshaft isn't locking up when you push the button?


Email me some larger pics and I can help you with all that stuff. I just swapped out a engine in a '93 S10-Blazer this past summer.
Link to the swap.
http://chevytruckworld.tenmagazines.com/account-photos.asp?album=18998

Nope, T-case isn't shifting. I suspect its not getting power now. No blown fuse. Something isn't hooked up or is severed.

At the switch, I get no power at any of the switch pins to ground, switch tests out ok. I'm wondering if there is some sort of control loop under the hood that must show certain conditions prior to t-case engagement.


I think if I keep the truck I'll want a manual transfercase, I don't trust the electronic stuff.

Thanks
Sam

Used NP231 will be cheaper then replacing the electronic motor in the t-case.

Engine on is hte only requirement I know of, power through the ignition swtich.