Hello, i just bought a 1979 gmc 3/4 ton 4 wheeldrive pick up, it has a 400 small block, automatic. It snowed up here today about 6 inches so i went out to plow , my truck jus spun when trying to plow. In reverce it never misses a beat but going forward it will kick out of 4 wheeldrive. sometimes if i hold the brake it will kick in or start off real slow it will kick in. When im trying to move ahead i can hear something clicking like the transfer is not in or a hub is not enguaged. I think i have the np203 transfer but not sure. im just useing the truck for a yard plow truck. anybody got any ideas? thanks ......steve
if you have a full time, did you throw it in hi-lock or low-lock, if you didnt then you have 2wd. and if you were graced with an np205, did you lock them hubs? sounds stupid but it happens, or it could be a lack of fluid? or maybe an internal issue?, anywho good luck on that.
If you've got the np205, or np208 (whichever is for that year, I don't remember), and if it's got those OEM automatically locking hubs (they don't have a dial), like mine used too, they dry up from lack of use. And...click, click, click, click, after you pull the t-case into 4Hi, or 4Lo. I spent $70 and slapped a set of Warn Premiums on. [img]images/graemlins/cool.gif[/img]
Yeah my '83 had 'em, with the cool lookin 4x4 sticker that I miss. But, I've seen Dial-less, and sticker-less older ones. Just a slightly domed metal cap on the hub. I can only assume it's some auto locking hub.
probably the ones with the plain jane half domed cap are the full tim hubs that is basically just a cover. Anyways, back to the problem at hand.... [img]images/graemlins/grin.gif[/img]
Probably first need to ID what t-case you have. Does it have a lo loc and hi loc position then it is a NP203. If it shifts like this:
2hi-then it is a NP205
and if it shifts like this:
4lo- then it is a NP208.
Hope that make sense.
Yes, i do have 4lo loc and 4 hi loc so i guess it is a np203. I checked the fluid , made sure the lever wasent hitting the body and checked the adjustment. The mechanic and my work told me to check to make sure the front shaft wasent spining inside the slip joint so i put the truck against a rock and had my wife try to make it slip..... everything was turning......so i figured id check my axle shafts after i read 83gmck2500's post......well he was right , my axle shafts are turning like their saposed to and the hub was clicking. Now.......its just a yard truck so can i take it apart and lube them up or should i opt for new hubs? I checked northernautoparts.com and found a set for $49.99 , Thanks everyone for all your help.........steve