HOrnbrod

Pete, when you trimmed the bushing shaft, did you simply grind them down? Did the heat generated harm the rubber?

Thanks Joel. The measured lengths from the center of the yoke U-joint hole to the end of the slip shaft are: MJ Yoke: 6-1/8" YJ Yoke: 5-3/4"

Here's a better pic comparing the two: Image Not Found

I picked up a YJ slip yoke which I was going to install to get the extra 1/2" spline length (or so I thought) before I brought my driveshaft to be balanced. The YJ yoke is actually 5/8" shorter than the yoke I have on my 2WD w. AW4 now, which measures 4-5/8" from the base of the "Y" to the end of the slip shaft. The YJ yoke measurement is 4". WTF?? Does anyone have any slip yokes laying around with a measurement greater than 4-5/8"? Thanks

Yeah, please keep in touch as I've been thinking of doing the same thing. Got the Xplodes in the door already, with the Mitsu AM/FM/CD player head, and need to upgrade the rear speakers. This is the ideal way to go and the built in amp should be just enough.

You did not mention what year minivan these speakers came from. The other two connections were used to power the built-in amplifiers. These speakers were used from the middle 80's through 2000 or so. First ID the "normal" speaker wires by hooking up a 9V battery across two of the wires and listen for a POP noise in the speaker. Not harmful. Then look at the colors of the other two wires. The 12- wire color will "most" likely be BLK, GRY, or BRN, with possible a stripe color. The 12+ wire should be connected to an ignition switched source. Hope this helps

I have a new (to me) YJ slip yoke coming, about 1/2" longer than stock, so I'll install that w. a new joint, then have the shaft balanced and hope it helps..........

No pics(no digital camera) I'm just gonna tighten the new u-bolts down & keep a close eye on'em for a while. Should be fine. Probably won't even use a torque wrench, since it won't be accurate against the warped surface. BTW, 40# don't seem like much. I figured at least 90. Yes, 90 ft/lbs is the spec for an MJ.

No, they are not all bent like this. Some pics would help. Also, is it a LB or SB? Different shock mounts.

I've been having vibes for about a month between 35-45 MPH, and have eliminated the wheels/tires ("borrowed" a different set, no change) and the steering and suspension. I changed my rear U-joint and the vibes nearly disappeared, but they are still there and at the same speed. Went to a local driveshaft shop and they checked the shaft out with a dial indicator, and it ran true. He also pulled the driveshaft to check the U-joints and they were okay. The tech recommended balancing (they did not have the capability - machine down) and also to replace the front slip yoke with one about 1/2" longer to compensate for the lift. According to the tech, the pinion angle was okay, and this makes sense since I have had my 3" lift for a couple of years with no vibes until recently. And on the way home, the vibes were worse, plus there was a new one at about 70 MPH. When I got home, I pulled the driveshaft, rotated it 180 degrees, bolted it back up, now the vibes are very minimal again. So, as opsled pointed out in my previous posts, my vibes are almost certainly a driveline problem, and I'm going to get the shaft balanced. But first I would like to put a 3/8"- 5/8" longer slip yoke up front into the AW4 if such an animal exists. Does anyone know? I've heard a TJ yoke was slightly longer, but do not know any details. Thanks for all the help guys.

They are on the linkage, inside the cowel behind the hood. You have to first remove the cowel, then remove the wiper motor and it comes out through the cowel opening. On it you'll see three white nylon bushings. Those are the culprits. The replacements are readily available in the HELP! line of goodies at all the parts stores, but they aren't listed correctly. Ignore everything they say about year and makes and models. You need HELP! part number 49445. The kit will include six bushings, three each of two types. You need the smaller white ones. The larger milky-colored ones? God only knows what they fit. Squirt a bit of white lithium grease into each bushing before you press it onto the ball stud on the linkage -- they'll last longer. X2. The grease and a small vise are used to easily press the new bushings on. One other thing, I had a heck of a time getting the wiper motor and linkage back into the cavity, probably because I'm a tard in some things. It comes out only one way, and goes back in the same way. Pay close attention when wriggling the assembly out.

Did you ever get the Chevy van driveshaft adapted to your MJ yet? I went to the driveshaft shop today with my 91 long bed and the tech said although my driveshaft checked out straight with the dial indicator on the truck, he recommended to have it balanced (his shop did not have the machine to do it). He also recommended adapting a similar length or longer Chevy or Ford shaft to gain another 3/8-5/8" length on the AW4 slip yoke to compensate for my 3" lift. I guess a lot of 80's era Ford and Chevys have the 3.5" Spicer-type U-joints with the outside clips. I'm still having slight vibes between 35-45 MPH, but not nearly as badly as before since I changed the U-joints. But still bad enough to be annoying. Any suggestions as to the best non-MJ driveshaft to try in my MJ longbed w. AW-4 tranny?

Pulled the driveshaft this morning and the rear U-joint was binding on the bearings of the driveshaft yoke. Removed the joint and the bearing cups were well greased. So I pressed in a new joint and cracked my Craftsman vice at the cast iron base while doing so and had to finish up with a BFH and a big brass punch. The new joint was good and tight with no binding. Reinstalled the driveshaft the same way it came out and went for a spin. The vibes are all but gone. There are still some very minor vibes at the same 35-45 MPH band, but you really have to strain to feel them. So all-in-all about an 80% improvement. But am still going to the driveshaft shop next Tuesday to spin the shaft. So a definite driveline problem.........

Thats a good idea (wish I would have thought of it years ago). Getting it to balance that way probably won't happen but if putting a few clamps on the shaft changes your vibration it would be an indicator that you are on the right track. opsled I picked up a couple of new U-joints this afternoon, and will install tomorrow. WTH, it can't hurt. The guy at the driveshaft shop said since the vibes are happening at kind of low speeds (35-45 MPH), U-joints are most likely the cause. According to him, normally an unbalanced shaft shows vibes at 55+, and has harmonics further up the MPH range. My vibes are strictly at 35-45, and I can go on up to 95 MPH w. no more vibes. If the new U-joints do not cure the vibes, I try the hose clamp trick. Dayem, what a PITA

Thanks Tom. I think I can now safely eliminate the wheels/tires now since the vibes do not change when using a different wheel/tire set. But knowing what Road Force balancing is now I'm sure will help me in the future. When I changed U-joints last year or so I used the Spicer greasable ones, and have kept them greased. But maybe they can go bad quickly too - hope so!

opsled, I think you are right on the money. I managed to scrounge up another set of wheels and tires this morning, mounted all four, and no change in the vibrations. ON at 35, OFF at 45. It's like a high frequency vibe, and you can feel it mostly by the seat of your pants, and is slightly worse under acceleration. So that eliminates the tires & wheels for sure. I have no handling issues, but did crawl under and tighten everything up to be sure. I changed the front coils and rear leaf packs about 1-1/2 years ago when I did my 2-1/2" - 3" lift, but had no vibes at all until about a month ago, which got worse after we did the gear change. So next is the driveshaft. I did find a shop in Huntsville, AL that has an excellent rep, and will bring the MJ there next Tuesday. So until then, after I cool down a little, I'll pull the driveshaft again and check the joints closely. Might put it back in 180 degrees out to see if it changes things. One thing about these vibes, they are very consistent. One friend said try fastening a stainless steel hose clamp around each end of the driveshaft just to see if things change, and attempt to do a redneck balance by moving them in or out. Don't know about that. But many thanks for your words of wisdom, and I feel like I'm finally zeroing in on the problem.

New leaf packs a year ago, recent alignment after my modest 2-1/2" lift, caster was right on. Rear is about 1" higher than the front. This vibe started like a month ago, and was made slightly worse after regearing. Before all was well. Now it's getting progressively worse the more I drive it. Not unbearable yet, like DW, but need to find what's causing it before it progresses. Dayem, lots of probable/possible causes, just have to eliminate and work down. Seems the most common consensus is tires first, so I'll find another set to stick on and either lay that to bed, or move on to the driveline. All new stuff for me............. :oops:

Nope. New isn't necessarily perfect. Manufacturer defects, and the occasional one that didn't have as superior of a build quality, but it's not visible when leaving the factory. My buddy's TJ, all the sudden, one day, it would ride fine till about 35mph, and then all hell would break loose for vibration. Threw it up on a lift, balanced and rotated the tires, tightened any bolt you could set your eyes on underneath, shook everything checking for worn out bushings or anything, seemed perfectly fine. take it out for a test drive, did it again, but slightly different feeling, about the same speed. Back on the lift, pull all the tires, road force balance them, and quickly notice one is a little egg shaped. a section of tire, the entire width of the tire, and about 15-18 inches long was about 1/4" higher than the rest of the tire. Put that on the spare tire carrier, balanced the spare before installing, threw all the tires back on and handed the keys to my buddy. He was quite happy. When he asked what the problem was, I showed him the tire on the carrier, and he was quite surprised. The tires had under 2500 miles on them when this all happened. Only thing I miss about college was the 2 post lifts and the road force balancer... :cry: Thanks Joel, and to everyone for all the replies. This is the first I have heard about road force balancing. Today I went to the best tire shop I know in my AO w. the best rep, they even do the "true" high speed balancing that makes a square tire round by shaving. My tires are 31" Goodrich T/As. They swore the tires were fine, and did a dynamic balace from scratch (I pulled the weights before going there). And I do have an unused spare. So how do I find out if any other shops have road force balancing capability? Remember, this is Alabama.... :roll: Call in advance? Must be a special Hunter machine?

Stealing Pete's pics post, you have one of the two below. Most likely the D35.

If it's on the vehicle, easiest way is to wriggle a mirror up in there and see if you can read the part number, then cross reference it.

Yeah CW, tires seem like the logical culprit and that's what I'm hoping it is. But I did rotate the fronts with the rears, and it did absolutely nothing, no change. I have a set of original 235x75x15 tires and wheels over at my bro-in-law's house. I suppose I could slide over there and stick them on and see what happens. But he's 60 miles away. Wait - I do have two here (also 235s), but would putting just two on give any accurate indications? Guess I could try the front then the back. Or would a complete set be better?

Just did another tour under the heep tightening everything I could get at. Found nothing abnormal. Checked the UCAs and LCAs, new tierod about six montha ago, and the trackbar bolts (all). About a month ago, I did regear my D35 (3.55 to 4.11), so naturally we pulled the driveshaft. I did have very slight vibes at the same speed range pre-regearing, but nothing like it is now. I marked the yoke and the driveshaft and reinstalled it the same way it came out. The U-joints I installed about 1-1/2 years ago, maybe 7K on them (don't drive it all that much). They are greasable, and I have kept them greased. There is no slop in the driveshaft, but I did notice some up and down movement on the slip yoke where the driveshaft slips into the AW4. I don't know how much movement is permissable, but the U-joint seems tight. Can my U-joints be shot already? Your logic seems right on since these vibes mostly started (or got worse) when we pulled the driveshaft and regeared. That was my first time, and it took three tries to get the preload on the pinion right. Just as an afterthought, could a too loose or tight pinion nut cause vibes in the drivetrain? I guess next step is to replace the U-joints, then check the driveshaft balance. That front slip yoke has be a bit cioncerned though. And today at the tire shop we did jack it up and run it up to 65MPH with no vibes. Wouldn't most driveline problems show up doing this?

Wouldn't that show up on the balance machine?

My tires are new, less than 2000 miles on them. Been under tightening everything. The steering box bolts were the only thing I found, and they weren't really loose, but I did take a turn or so with a big cheater bar. Everything else was tight. Just got back from a road test, and it's still there. Seems to be worse when lightly accelerating, then slacks off when letting up on the gas.

It's 2WD.