Pinion gear play: should I worry?

[Starliner]

Its a good clunk that gives, with play about 3/8" travel.
Big job?
Ignore it?
I see rebuild kits on Rock for $100 or so.
If I can doi it on the ground, I could put it on my todo list.

Everything else is coming together.
Thanks to you guys.

[ArdWrknTrk]

3/8" in & out???  😳

Does the yoke wiggle side to side at all (out of gear, wheels chocked)

Is this a D70 or 80 in your bucket truck?
Rebuilding my 10.25 was a months long odyssey of incorrect parts and broken tools.

[Starliner]

Geeze, i only checked clockwise/counterclockwise play.
The driveshaft is pretty tight to it.

It is noticable when I put it on gear, Jim.
A pretty strong clunk.

My buddy, a lifelong wrencher said meh, it's an old truck, no biggie.

Then again, he isn't phased by much these days.

D70 or 80, don't know what that is.

I will check side to side.

A MONTH? no thanks. I would rather run it til it breaks.

I AM changing gear oil fully. God only knows what is in there.

[ArdWrknTrk]

Like your friend said, rotational play is probably ok.
Any in and out is very bad.

[viven44]

Is this your truck with the 8.8” rear end ?

Lift the rear tires off the ground and see how much rotational play they have …. A lot of play there would indicate wear on axle splines… That’s probably part of that clunk.

Fluid is probably high on natural abrasives!

And agree with Jim, in and out play would indicate pinion nut or crush sleeve isn’t doing it’s job.. that would be bad

[ArdWrknTrk]

If it's an '84 F-250 it should have a D60 out back.

[viven44]

I’m just going off the signature

[ArdWrknTrk]

And I'm stupid enough to go to Joe's introductory post, where he mentioned the 250.

But this is why it's good to have that info in the thread title....

[mat in tn]

being an 83, I would expect it to be a 9". either way the oil is a good thing to change/inspect. are there any leaks? leaks are an excellent sign of where the wear and slop is. pinion seals are most susceptible to this as they sling oil like a fan. but the 9"is a different animal entirely from the rear loading differentials.

[viven44]

If its the same 83 that Joe wanted to ID a few days ago, we established only based on the VIN TAG that it was an 8.8"......

If Joe has a picture of the rear end, showing the front and back we can ID it more definitively. Since 9" swaps are very common.

[mat in tn]

if it's an 8.8 then it's a very common axle used in a ton of vehicles and has great support as far as parts go. the spider gears are a bit of a weak link on neglected units. this is very often the rotational play. spline wear is part, spider gear engagement is part, pin wear is part, added together then added to the ring and pinion lash, it can certainly feel sloppy. often when inspecting one of these (driveshaft removed) I will hold the pinion flange, rotate back and forth to "feel" what is going on. usually, I can feel the lash before feeling the spider gears movement. the spiders have an almost "spring loaded" feel. if it is minimal then I would not be alarmed. but if it is noticed mostly when changing from forward to reverse or vice versa. that is going to be ring and pinion lash. whether due to bearings or bearing adjustment, crush sleeve etc. of course this is assuming that u joints have been ruled out. universal joints in the driveshaft are far more likely.

[Starliner]

Holy sh$$, do I see a tag on the rear diff?
How did I miss that.
If stock, it is an 8.8.
I will jack the rear up and eval as you guys said.

Thanks!

[viven44]

I totally agree with that.... all of that adding up makes it clunky! I adjusted my backlash to ~10000s ... it was at 35000~~!! but still there is a small clunk.

When Joe has the rear axle cover off it would be best if Joe can follow this video below and figure out where the play is...

This video does a nice job of explaining it

https://youtu.be/n96vqaNs--M?si=YkoeuBR3RJvds1TN

[mat in tn]

that there is an 8.8!

[Starliner]

I will definitely follow that video.

I saw another one that showers a fluid change, but the guy used 75w140.
Same vintage as my truck.

I wont be doing that.

That D60 in my 84 F250HD was great.