I have been having a issue with my 96 blazer. When i put it in reverse and give it gas it will shudder for the first few feet then stop. but i can be on a hill and roll backward and it wont do it. I have replaced and changed my tranny fluid and filter. I have added tranny medic to it. Nothing really made a difference. Also the blazer shifts great going down the road, no vibration at any other times. I was playing with my 4 wheel drive the other day and noticed when i put it in 4 low reverse i could not make it shudder at all.((Note 4 wheel drive is out, so front wheels was not pulling)) but it would shudder in 4 high. So that makes me wonder why it wont shudder in low but will in high. Could this be the tranny or my engine having a problem applying power to reverse since its a higher gear ratio.

 

Motor/trans mounts making you feel things more? The higher gear would mean that the engine would have to work harder to move the truck. Reverse is a higher gear than 1st so it could be an ignition system (plugs, wires, cap, rotor, coil, ICM, etc) issue.

 

Im still haveing this problem, I have noticed that when i put it into reverse and slightly apply gas it wont vibrate, but when it gets a little torque it does. Its like im running down a railroad track. Im going to take it somewhere and have it checked out while on stands or a lift to see what is causing it.

 

It sounds like reverse is starting to fail. Low fluid pressure maybe? I know these trans had issues. Find a trans shop and talk to someone. usually they will know right away just from you telling them what its doing.

 

Today I was backing out of a parking lot, and my truck started to make the vibration again and the sounds. My friend looked at my wheels as i was backin up and said my rear passenger wheel was vibrateing bad. I went to my uncles house, he looked at it as i backed up, and he noticed that same wheel was the source of my vibration. When i got home today, I jacked my truck up under the rear end so both back wheels would be off the ground. I put my truck in drive and accelerated, I heard my drivers side rear wheel starting whinning around 35 mph, but no vibration. I put my truck into reverse, and accelerated, but no vibration/sounds. I then applied the brakes, then power breaked in reverse. Then there was the vibration/shudder i have been haveing. I done it a few more time with the breaks applied, it would vibrate from about 0-3 mph in reverse but stop at anything over 10mph. I then let off the breaks and accelerated, but no vibration. I put my truck in park, got out and moved my wheels back and forth and pushed and pulled. I found a problem, my wheels have play in them when pushing and pulling, they will clank. I checked my lugnuts, they all tight, my hub has looked like it has gotten hot before. I have a few thoughts as of what it might be. 1 maybe my axles are going back, or 2 my wheel bearings are bad and causing some play, and maybe my vibrations. But i do beleive it is not my tranny or driveshaft/u-joint from what i had thought previously.

 

today i had a good chance to look at things. I inspected my wheels and hubs, and rear end fluid. Everything seemed ok. I checked my tranny fuse it was good, but then i had the idea of takeing out my tranny fuse out and driveing it in reverse, It did not viberate then, but had no power in drive. I plugged my fuse back in and my it worked fine. I shut off my truck waited and restarted it and the problems returned, removed fuse and problem went away again. So why would my problem go away without a fuse in, and then return when i restart my tuck with the fuse.

 

I beleive I am haveing an electrical problem. I got out and was playing with the tranny fuse again today. As i unplugged it and replugged it, i heard something click in or around my transfer case. I tried out my 4 wheel drive which was not working since i had the vehicle. And it worked. And my vibration was gone also. But as soon as i shut off my truck and waited and turned my truck back on my 4x4 was not working and my vibration returned. So there is something causing both problems.