Engine/Transmission (1994 - 1998) vacuum leak in drivetrain

[Advantage Take]

had a vacuum problem for a while. fixed a big leak, but now there's a smaller one i'm tryin to pin down. the pump holds 27" but there's only 15" on the system untill the line leading down to the transmission is crimped then its back up to 27". there is also more than usual vapor in the crank-case vent. i was wondering if there was a vacuum switch on the transmission or t-case as well as the 4-wheel drive canister? how would i get to it?

 

[vssman]

There's a switch on top of the T-case with a large rubber connector for the 4 vacuum lines that go to the pump, atmosphere, and vacuum motor on the front axle. There are also several areas where the line transitions from rubber to steel and back to rubber. Each spot can be a place where you can get a leak. I'd start with the T-case switch as the rubber plug tends to swell from oil.

 

[Advantage Take]

thanks. thats what i need to know. i guess i have a leak somwhere in that switch or in the vacuum canister for the front axle. it can't be bad though cause the pump can hold the system at 15" which makes everything work, just a little slow though.

 

[vssman]

You really should make sure the vacuum is correct at the front axle. I had a similar problem which resulted in delayed front axle engagement and thus damaging the transfer case. I've since switched from the vacuum system to a cable system.

 

[RCrocker]

FYI Leaks

I found 2 leaks on mine (12 V), first was the lines at the front of the transfercase where they transfer from steel to rubber. Rubber plug was very loose replacedwith a new one. The second was at the T from the pump to the brake booster my prime-loc filter re-locator had dripped fuel on the fittin and swelled it. Only pulling 15 in of vacuum at the pump though possibly my pump going bad ???

 

[vssman]

I removed the lines from the tee up in the engine bay all the way down to the vac motor. I left the vac switch on the transfer case. I did this more for "therapeutic" purposes than anything else