Hey Team!

So I took the old girl in for a check and they said "Play in the U Joints" and "Pinion Seal".... (along with other things)
I got under the truck and gave the joints a shake - Front and rear shook maybe 1-2mm.

Now a couple of questions:
- How long will I get out of the current u joints with a 1-2mm shake?
- How hard are they to replace?
- Do I just do 4 (2 in the rear and 2 in the front)?
- Do I do the pinion at the same time?

Thanks in advance!

1) if the universals have that much slop in them they are shot, they need to be replaced. It's unclear from your post if you are just talking about the front and rear driveshafts or also the front axle joints but in any case they shouldn't have slop in the joint.
2) they are not hard to replace if you have done it before, if not it can take a while and it can be done wrong.
3. How bad is the pinion seal leaking? If it's just a little damp I probably wouldn't worry about it. If it's actually dripping/leaving a puddle you ought to get it fixed before you run the diff dry

There is no way to tell how long you'll have. 1-2mm is a lot, so do them asap.

Watch a YouTube video:




Now, the pinion seal is a different story. There is a LOT of wrong info out there, and it's often debated.
The only correct way to replace the pinion seal (without removing the entire pinion gear) is to mark the nut in relation to the yoke and count the turns it takes to remove the nut. The other correct way is to completely disassemble the differential. There are 2 torque specs in the FSM that are discussed. The first is the "don't exceed this torque when crushing the crush sleeve" torque, and the other is "pinion preload torque", as measured by a flexible beam inch-lb torque wrench. You DO NOT TORQUE THE PINION TO A SPECIFIC VALUE. That is wrong wrong. You also don't "torque it until you feel enough gear backlash". That's another big no-no.

Anyway, the pinion seal is easy to replace, but can also be screwed up by an improperly trained technician. The steps are simple. Match mark the nut, loosen the nut, count the turns, dig the old seal out, drive new seal in, tighten the pinion nut until the match marks are aligned. That's it.

Commence the arguments.

Thanks mate!

Yeah just the front and rear on the driveshaft seem to have issues, so was going to do those..... 4 total?
2. Never done them and wrong is no good. I will get online and watch a bunch of videos before doing them.
3. I have never seen a puddle or anything under the truck at the point.... I have seen leaks under the motor, but never that far back.
I will get under it tomorrow and take a pic.

Cheers!

Thanks mate, I will get on those videos this week and order the parts.

I have a feeling this might be out my level of expertise. I will check the leak tomorrow and take a pic for here, hopefully it is not bad and I can hold out a little longer.

Cheers!

Agreen, no argument and a slight thread drift, but what do you do to set pinion preload in my case where my donor diff came to me without a yoke? The diff was mostly complete, missing one steering knuckle and the brakes which are easily replaced but I am a little concerned with the pinion preload. I do have the ring gear and carrier out as I'm putting new housing seals in, basically an almost complete rebuild. The bearings seem to be fine and the ring and pinion teeth look good.

The right way? Rebuild it. My way? Pull the ring and carrier out, pop the pinion gear out, replace the crush sleeve and torque it down until you get the correct pinion preload (12-15 in-lbs). Then paint the teeth of the ring and check for the correct gear contact pattern.

no crush sleeve on the D30 if I am correct. Just shims. For clarification, I check the preload with just the pinion installed, no ring gear?

Word of caution on replacing u-joints in a double-carden driveshaft, or more specifically, paying someone else to do it; it's not uncommon to be near the cost of a new shaft...

Marking the nut and shaft is my preferred way to replace the seal; pretty much impossible not to get it "retorqued" exactly like it was so long as you don't do anything super stupid...

don't use chinese u joints!!

Is there a way to know if the u-joints were made in China when ordering from, say, Rock Auto? Are Moog's or Dana/Spicer still made in the states?

I bought Spicers for my 97 probably 2 years ago. All have "Made in USA" on the box.

who knows anymore. Shop local?

BTW
if someone thinks the pinion seal needs to be replaced you ought to check the diff juice NOW if you haven't recently just in case they are right

Those videos make it look manageable for sure.... and I think I can rent a kit from Autozone to do the job too.

Just to confirm, I need 4 joints to do the front and rear driveshaft?

Cheers!