shuddering problem....driveshaft lengthened?? long...but help!

[BobCarter]

Hey guys. I took my explorer in today because its been shuddering real bad on tight slow speed turns... or when under load. Anyways....i took it in thinking that the LSD was going bad...cause thats just what it felt like. But come to find out that they mechanic thinks its a seal/bearing on the tail end of my transmission....says theres a lot of play there that is causing it to bind. Also, i removed my 5th shock (trac bar) because I've lifted the rear about 2 1/2-3" and he said i need to put it back on because it keeps the pinion from trying to torque over. To which he then proceeded to tell me i should probably get my driveshaft lengthed about 3/4" - 1" because the yoke is so short. So...my question is....on a lift as small as 2 1/2" is it normal to need a driveshaft lengthened? I've got friends with like 6-8" on their chevy's with no problem. He's going to go ahead and replace the seal and bearing...then see if that helps the shudder. Do I really need to re-install the 5th shock...its soo weak i dont see how it could help? THANKS!!!!

 

[dzk007]

I would put the 5th shock back on or even replace it with a new one. Anything that keeps the driveline more stable is a good thing for longgevity.
Also, I would inspect the fit of the yoke and output shaft for slop. If there's a lot of slop in there you could just rip up the bearing you are having replaced.

 

[Robert]

Find a new mechanic. First the shock is put on there to dampen vibrations from the rear axle at speed. It has nothing to do with preventing the pinion from torqueing over. I assume what he is trying to say is "axle wrap". In either case, that isn't what it is for. How did you lift the rear? I doubt if you need a lengthened driveshaft either. I have lifted my rear up 1 1/2" - 2" using longer shackles. I don't even think you need a longer driveshaft until you go to 4" or more and that might only be for the front. Is you Explorer AWD? If so, it might be related to power inadvertantly getting sent to the front. If it is 2WD then it is probably related to the front suspension. How is your alignment? You need to take it to someone that is familiar with the Explorer, not a Mechanic that might see one or two a month.

edit: now that I can see your profile since I am out of the reply screen, it looks like all you did to the rear was install Warrior shackles. If that is the case, then you have the same shackles that many, many people here (including myself) have installed. We did not need a longer driveshaft as a result. You can also do a serch for the 5th shock and you'll find dozens of people that have removed theirs for the better.

 

[BobCarter]

Yeah....i figured that taking the 5th shock off wasn't really an issue as far as the torqueing over of the axle...it just seemed too weak to prevent that. Question though...on our driveshafts....does the yoke actually have like a slip in it...or does it just slide in and out of the transmission seal? I looked and my driveshaft really only looks to be out about 1/4" - 3/8"... as far as my life goes. I have the shackles as well as the superprings...so its about 2 1/2" - 3" higher in the rear.

 

[Robert]

The rear driveshaft has a slip yoke at the front of it. I have my stock mono-leaf rear spring so mine isn't quite as high as yours is. It's possible that yours might be out a little more. Basically the splined front end of the driveshaft slides into the slip yoke. If you remove the black rubber seal and jack the rear of your vehicle up by the frame letting your rear end drop, you could see how mucy more it would take to come completely out. Mark the slip yoke when it is out as far as it will come. Then remove your rear driveshaft bolts from the differential flange and pull it all the way out. I don't know what a safe amount is, but if you have at least 2" still inside the slip yoke you are probably safe. If you only have about 1/2" left in then you might benefit from a longer driveshaft.

 

[BobCarter]

Well...i just got back from the shop. He took out the seal from the rear of my tranny and it was shot. So after replacing it and putting the driveshaft back in...we went for a ride and it still shudders just as bad. I left it with him for a little while longer. He really is stressing it to me to have my driveshaft lengthened...I looked and it sticks out about an 1" farther than normal...which probably isn't good. He went on and on about how I've messed up the anlges of the suspension and axle by lifting it. I've probably only lifted it like 2 1/2" - 3". Anyways, I want to get the driveshaft made longer, but hate to pay that kind of money, and it not be the problem.

 

[dzk007]

Could it be bent?

Did you hit anything with it? Look for scrapes or other telltale signs. If you want to be sure, jack up the rear wheels and spin the tires in 1st gear while you watch the shaft. Could it be a bad joint or joint installation? With the engine off, the shaft should rotate a little but that's all it should do. Play in any joint will tell you where the problem is.