Transfer case clunks!

[CountryGrl]

Hi Y'all! I have a 1988 GMC K1500, with 160K miles on it. I live on a dirt road so I use the 4-wheel drive all the time. This was my late husbands baby and he did all the work himself. It's basically all stock. I'm learning to work on it and can do the basics. However, I know absolutely nothing about the transfer case and what maintenance I should be doing. Lately, it is clunking every time I engage the 4 wheel drive, and when I put it in gear, it does not catch right away. I know enough to treat it gently so I dont blow something. Today I was hauling something up a hill and when I tried to put it into 4LO, it popped out! Please help! Thanks!

 

[evilunclegrimace]

There are a few things to check, Front diff lube level, front drive shaft U joints, are the front diff mounts tight? Are the front out drive axle CV joints loose/worn? Does the clunk happen while moving and engaging the 4WD? Or does it clunk while moving and the 4WD is already engaged?

As far as the T case jumping out of gear check the linkage rod bushing for wear or rust build up make sure the T case bolts are tight at the adapter, make sure that the sector shaft is not loose

 

[CountryGrl]

There are a few things to check, Front diff lube level, front drive shaft U joints, are the front diff mounts tight? Are the front out drive axle CV joints loose/worn? Does the clunk happen while moving and engaging the 4WD? Or does it clunk while moving and the 4WD is already engaged?

As far as the T case jumping out of gear check the linkage rod bushing for wear or rust build up make sure the T case bolts are tight at the adapter, make sure that the sector shaft is not loose

UGHH.. I totally understand what you are telling me, but I also know it's out of my league at the moment. The last time someone worked on my truck, I got taken for a ride! I need somebody to show me! Anybody in Northern CA willing to help? I know more about my truck than anyone I know!
Thanks for the input! I totally appreciate it!