a whole lotta shakin

Hey everyone...im having more problems with my truck...just when i thought i fixed em all. Anyway my truck is a 1990 jimmy s15 4.3tbi 4x4. My problem is that it has started shaking and rattling. The shake you can notice when its in park and will continue to shake in drive until I hit about 55-60kmph then the faster i go the more it smooths out till i hit about 120ish. The rattle i dont know if it is related or not does not appear till I hit about second gear...occasionally you can hear it at other times but in second while accelerating is definately when it is most noticable. If anyone could please help me out with this it would me much appreciated...this truck has long frustrated me and id really just like it to work properly for once.

Thanks

also forgot to mention...its worse when its cold than when its at normal op. temp.

Check your motor mounts.... That age, if they haven't been replaced (even if they have) more than likely they're seperated. (The rubber from metal plate, or the rubber is broken) Pretty common problem.

i replaced the mounts about a year ago...but ill check them anyway

Ok so as i thought the mounts are fine. But after listening to the rattle the last couple days ive noticed a couple more things. It will only rattle and shake when it is in gear, doesnt do it in park. Another thing is i noticed that the sound is coming from the bottom end/transmission area. Now i have also noticed that the shake and the rattle appear at the same time so i assume they are related. It doesnt have any problem shifting gears or anything so i dunno could this be a tranny problem?

U-joints.

how do i check u joints?

and if it was u-joints wouldnt it shake all the time...not just at lower speeds?

and if it was u-joints wouldnt it shake all the time...not just at lower speeds?

No, it is more prominent while driving.

ok that wasnt what i asked...i said wouldnt it shake more at higher speeds? Because the truck doesnt shake once im going over 60kmh and it also DOES shake when i am at a complete stop....so that doesnt really make sense that it could be u-joints. But i did check them anyway and they were fine, so any other ideas of what it could be? As i said before, the shake/rattle comes as soon as it is put it into gear, not as soon as i start moving, and then goes away after about 60kmh when it changes gears. The sound is coming from the bottom end, possibly transmission area.

ok that wasnt what i asked...i said wouldnt it shake more at higher speeds? Because the truck doesnt shake once im going over 60kmh and it also DOES shake when i am at a complete stop....so that doesnt really make sense that it could be u-joints. But i did check them anyway and they were fine, so any other ideas of what it could be? As i said before, the shake/rattle comes as soon as it is put it into gear, not as soon as i start moving, and then goes away after about 60kmh when it changes gears. The sound is coming from the bottom end, possibly transmission area.

Check your motor and tranny mounts.