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1993 Dodge Dakota LE, 5.2L, Auto Trans, 2WD, 180,000 miles, original owner
I’ve had my truck at a shop since last Wednesday to replace the center support bearing and the three u-joints on my two-piece driveshaft. I took it to the shop because I did not want to do the job myself. I don’t have a lift or a press and I’m too old to be laying on a cement floor and wacking on driveshafts and u-joints. Needless to say I’m pissed that they haven’t even started working on it. They’ve only called to say the parts need replacing. DUH! I already knew that!
Anyway, I’m calling them in the morning and telling them to either get the job done tomorrow or I’m coming in to get my truck. I may end up doing it myself after all.
Question: Are the three u-joints the same or are they all different? Also, I prefer greaseable u-joints. Any reason why I shouldn’t? Lastly, Spicer or Moog or both are good?
Greaseable U-joints are weaker in the web; but TBH, unless you've been spending much goat juice money on the motor, it won't make a rat's pattottie difference. Just be SURE to keep them lubed (and I prefer the moly based lubes personally, but any quality lube will do you.)
I'd be sure to buy the high line of either; the cheap Moog are, well, cheap. Moog ain't what it used to be since Federal Mogul bought them years ago. I'd actually probably go Spicer or Dana (same U-joint BTW!) if it were me.
Do NOT forget to pick up a new support bearing!
The RockAuto listing shows a Moog 246 or a SKF UJ246 - they show them at $13.06 and $14.17 respectively as I type this.
For the center bearing, I'd probably go with Timken HB88107A (shown at $20.79) because, well, Timken. The SKF HB88107B shows it comes with slingers; the Timken, not. That may be worth the extra $21 ($41.79 for the SKF). I dunno, I prefer Timken for no more reason than they quit making bearings in China because The Were No Damn Good. ( see
OK, Ralph. Here's the deal. I finally got the shop to get the job done. They replaced all three u-Joints. All three were not the same. He said nothing told him they were different when they went to order the parts but in fact one did not fit. So he actually had to measure the bore off the oddball and go from there. I believe it is the middle joint that is the oddball. I say that only because the grease zerk is on one of the end caps whilst the two end joints the zerk is in the middle. He told me two joints were kaput with one of them reduced to "powder" (I believe the one toward the tranny was pulverized). He did not replace the center support bearing. I was disappointed as I asked for it to be changed whether it needed it or not. Apparently that message did not get conveyed to Frank the mechanic. He told me that bearing was perfectly fine. While I agree the rubber casing was perfectly fine I was not sure about the bearing itself. He told me that was fine. So let's hope that bearing lasts awhile longer. Figured it was worth swapping while the driveshaft was off. Frank told me he'd have to send it out to change that bearing. Guess he doesn't have the right puller.
Here's the kicker and I want to pick your brain here. Is it possible my RPMs would significantly decrease by changing out the u-joints? I'm idling at 300 - 400. Prior, I was 650 - 750. Even cruising at 55 mph I'm down about 400 - 500ish RPMs. Will worn u-joints make that much of a difference?
Nope; U-joints make zip difference in idle speed (since the truck isn't even moving.)
OTOH, the knocking may have kept the tach working better. And now that the truck is riding better, the tach is settling down to a lower reading.
OTGH - These instruments are NOT precision grade instruments! Check your idle speed with an independent tachometer (say, one in a MT2500 if you have one; or with an automotive multimeter) to see if the tachometer is even accurate.
Of course it wouldn't make a difference. DUH! I should have known that. Truck not moving. DUH,, again! But I do find it very odd that the tach is reading a considerable difference. Nothing feels different. I would think I would know the difference between a 300 RPM idle and a 700 RPM idle. I tend to agree with both possibilities you guys bring up. Maybe the tach settled back in or the damn thing is just plain moody.
One more question. I'm no u-Joint aficionado but I have seen enough of them to know what they look like. I cannot say I have ever seen one with just one grease zerk on the endcap (Note bottom-most endcap with the zerk). None of the other three have them and there are no zerks inside. How common are these? I'd be curious to know the grease path of this one.
UPDATE: I think that's a Moog U-Joint (Super Strength line). Grease just shoots down the middle and crosses over to the middle of the other three bearings.
Driveshaft U-Joints
