after using 4wd for the first time this year I heard a chattering noise from the frt right. I was in 2w hi at the time. switched it into 4 wheel hi and out to 2 wheel hi. noise went away instantly. fine for a week then heard it again, but worse. this time I was decellerating down hill after driving about 12 miles at 65 mph. was doing about 35 at the time. pulled off of the road switch it into 4 w hi and back to 2w hi. problem gone. got on a dirt road shifted into 4 w lo and back to 4w hi and to 2 w hi no problems. since then I drove about 100 miles in 2w hi, which 60 of it was at highway speeds. no problems. plan on checking fluid levels this week. any other suggestions? I have never had any 4wd drive issues or problems. veh has about 210K I did change all fluids at about 100K using all synthetic at that time.

thanks,

bernie

 

Sounds like a bad transfer case vacuum switch. I've replaced several. The ball sticks inside allowing vacuum to be constantly applied to the front axle.

 

yea, that is what i was thinking after reading on line. I bought one a few years back in anticipation of this day. tomorrow I'm crawling under for a look. any idea where it is? I assume just unplug vacuum lines , unscrew and reverse.

thanks

bernie

 

correct it should be located on top near the front shaft

 

thanks

bernie

 

Mildly frustrating, three vac lines are connected and switch is keyed so it only goes back one way. First thread was hard, fat fingers, you will get it. Look for tranny fluid in lines.

 

All fixed for now. no tranny fluid which is good. Did find one problem, and hope I don't have a problem in the future. Evidently this switch was changed before I bought the vehicle. some of the threads on the trasfercase were stripped. luckily the shaft on the replacement valve were longer than the one i replaced. I wrapped it with teflon tape and it held tight. I asked a mechanic and he said it should be fine. just clean the outside and coat with black RTV, no loctite. If it doesn't hold, next step is helicoil. If I have to do a helicoil it might be easier to cut a hole in the floor from above for access.

thoughts?

right now it is working fine.

bernie