jac113

iTrader: (4)

Hey guys,
Got a '92 5.0/5spd with just under 200k on it. I got it with 196K and i'm guessing it still has the original engine/tranny.

The problem i'm having is I hear a whining/slight grinding while decelerating while in gear. The funny thing is that it resonates from the rear and when I take it out of gear it goes away. When I accelerate it does not make the noise.

Just installed a new clutch kit about 1,000 miles ago so new pp and throwout bearing so i'm thinking maybe a bad input shaft bearing.

Any ideas anyone?

thanks

matthufham

iTrader: (5)

could be in the rear end. take the driveshaft off and see how loose the pinion nut has gotten

big gear head

Yea, check the pinion nut.

jac113

iTrader: (4)

Hey guys,
I finally checked the pinion nut last night and got some bad news. Grabbed the pinion input(i know that's wrong) and moved it around and it had at least 1/8" to 3/16" play in it all around. Not sure if the bearding went bad frist or if the nut backed out. From what i've been reading it sounds like a rebuild or bearing replacement is inevitable. I have the slightest idea of how to tear it down and don't have the time or $ to do it. But what I do have is a limited slip rear out of a early 70's el camino ss. I can put that in but i'll have to get the brackets welded on the axle and put my rear disc on in too. This might be the cheapest way to go.

For the mean while i'm going to replace the pinion seal and torque down the nut to 100 + lbs(body weight) with my 18" breaker bar and hope for the best. If I can get 500 miles out of it without a whine i'll be happy.

One thing I never got was if the nut backs off and if you catch it early enough, how do you know how much to torque it back to without having to open it up and set bearing pre-load properly. Doing a pinion seal replacement is easy because pre-load is already set so you replace the pinion nut to where it was originally. If you don't know where the nut originally was aren't you just guessing on the pre-load forcing you to open up the diff to do it right or torque to 150 and hope it works???

thanks guys...

jmd

iTrader: (4)

does it rotate 1/8" or does it move laterally 1/8" ?

supr_fly03

iTrader: (2)

150ft lbs should work, just throw some thread locker on it.

SomeGuy25thZ

Anyone have a photo of the pinion nut? I am hearing the same sound under the same conditions in my 88 Iroc. Car only has 72k miles though. I did notice a leak in the rear end - clean fluid coming out, i just bought it and previous owner said he changed oil less than 1000 mi ago.

Could my sound just be some loss of fluid? the leak is real slow but just dont know how long its been going on for. Its been in my garage for over a month and just had a small puddle on the floor - enough to wipe with one sheet of bounty and still have some of the sheet left over.

I was thinking just change the fluid and address the leak, bad seal i guess. then see how it goes.

jac113

iTrader: (4)

mostly lateral from what I remember but will check it tonight when I get back on it. It started to rain pretty hard and I didn't have the 1 1/4" socket so I had to wrap it up.

Wouldn't radial play indicate too much play or a broken tooth or maybe stripped splines.

I've also read about people using sealant on the spline and seal. Any thoughts on this?

thanks again

jac113

iTrader: (4)

considering your mileage, a bad seal is likely the cause of the leak, and the leak the cause of the whine. There's a good youtube video on how to do it from A1Auto, just search pinion seal. Our pinion nut size is 1 1/4" though and here's the pic:

replace seal,torque nut to 150, fill with 80-90w and you should be good

jac113

iTrader: (4)

pic of pinion nut:

big gear head

The '70s El Camino rear end will not fit your car without MAJOR fabrication and modifications. It would be much easier for you to fix the rear end that you have than it would be to install this other rear end. Read this. https://www.thirdgen.org/forums/tran...axle-gear.html

supr_fly03

iTrader: (2)

I agree, even if you have to completely rebuild your rear, it will cost you less then just trying to fab stuff to mount that 12 bolt in your car.

If you can tighten the pinion nut and take the slop out of the pinion then I would pull the cover, make sure there is no damage inside (like the pinion backing into the carrier). If that looks good, pull the yoke off replace the seal (follow the directions in the above thread) and put some thread locker on the pinion nut and torque it down to 150ft lbs.

If there is damage, find some gears new or used and an install kit with new axle bearings/seals and put it back together following the thread Big Gear Head posted up.

jac113

iTrader: (4)

Update:
Just finished the job and real results are pending. It took me about 3 hours somehow. Things just seem to drag when i'm working on my car.

Last friday when I read how bad a whine could be I got spooked and had the maro towed to my mom's house instead of risking the drive home. So I get back under it today. I used a weak impact gun and a 2 gallon compressor and the pinion nut came off too easy. Didn't count the threads before i took it off but pretty sure it was backed out quite a bit. Popped off the old seal, cleaned p yoke and nut and let most of the oil drain out. Put some black silicone around the new seal and oil on inside ring and hammered it on. I found a trick to putting it on without a board to cover the whole seal is to hold one end in with a flat head an tap on the opposite end with a hammer.

This is where the job gets iffy. I put sealant on the yoke splines and slipped it on and I put some lok-tite on the (old)nut and started to tighten it down. The yoke didn't slide in all the way so I relied on my weak impact gun to do the finish it off and no luck. I probably can see two threads of the shaft and the yoke collar is still about 1/4" from the diff housing. Not sure if there should be a gap but my other diff's didn't have one. I had no choice but to drive it 1/2 mile to my house so I fillled it with oil and went on my way.

No whining from a 30 mph cruise. I still need to torque it down because i left the torsion arm on and didn't have much room to tighten it by hand, i'll be lucky if it was torqued to 100 '-lbs.

thanks all for the help...

jac113

iTrader: (4)

2nd Update:
Alright guys, kinda concerned now and lookin for feedback:

I didn't drive the car all week because I wanted to torque down the pinion nut as much as I could before I did. No noticeable leak but I still didn't have that piece of mind to where I felt comfortable driving it. So last night I get under it and I notice that the pinion seal had popped out against the yoke on the top side. It happened because of how the yoke did not got onto the pinion shaft enough to where it's "almost touching" the diff housing.

So I take the yoke off and hammer the rest of the seal in. Cleaned the threads and yoke and started reassembly. I push the yoke in as much as I can by had and drove it in the rest of the way with the impact on a 30 gallon compressor with the same results.

The p-yoke is still 1/4" from the diff housing. Is it possible that the shaft is able to come out 1/4" from the diff.? With the p yoke off the shaft has about 1/4 lateral movement and when rotated it'll probably move 1/4" radially also and will come in/out 1/8" when rotated.

So to help me understand how this works and why my seal popped out, i'm wondering if my pinion shaft has too much play and it overloaded the seal. Is this a sign of bad bearings???

thanks guys any help is appreciated!

jmd

iTrader: (4)

At this point (after having driven it in probable "not fully assembled" mode,) I'd pull it apart for a couple reasons. To pull and inspect the bearings (including races) (and frankly a new seal sounds like a good idea "just because." )

As far as the yoke distance, I don't know. Because, that's a visual "reference" and not a "specification." What you're looking for, as with any, is the in-lbs measurement of drag at the pinion to be 15(I think) on the pinion with the ring gear out of the way. That measurement on a used bearing set will of course be lower than a brand new bearing set.

The other thing I'd do is get a good ft-lbs torque wrench and torque the nut to spec by hand. (some guys w/ experience use an impact on a used nut / gearset. I don't.) Especially since you suspect the yoke is not fully on.

I think you know what you gotta do; everything over again, just to make sure it's right.

big gear head

You are planning a complete rear end replacement later, is that right? If so then torque the nut to 125 to 150 foot pounds and see if there is any movement in the pinion other than rotation. If there is then you have a bearing problem. If not then drive it and see what happens. If it makes noise then plan a rebuild or replace it.

jac113

iTrader: (4)

Thanks for the input guys. I appreciate both of ur comments jmd and gearhead. I think i'm going to drive it and hope for the best. I have more time than money but still not very much of either so a full inspection would just be a waste of my time and $. It'll cost more to rebuild than to just r/r with a used one from a junk yard, even if its an open diff.

To be honest, i've about had it with this car, should have done a better inspection when I bought it. I'm on the brink of considering trading it for something that is more road ready. Had this happen in summer i'd park it and walk to work and work on the car over time but it's rainy so I need some wheels to get around.

Gonna go the gear head route, there is no lateral play, just radial with the nut "tightened" down but I attribute that to being the yoke collar just being squeezed by the pinion seal, which is probly why the seal popped out on the short ride home. I'll put another mile on it and seal if the seal is coming out again. If not, i'll drive it 'til it breaks, if so, i'll park it and swap rears.

i've attached a pic to show you the gap. Biggest question i have when seeing this is why is the nut tight if the yoke is not being squeezed against anything??????

big gear head

That looks about right to me. The yoke seats against the outer pinion bearing, the outer pinion bearing seats against the crush spacer and the spacer seats against the step on the pinion shaft.

jac113

iTrader: (4)

aha, that makes sense. we'll see what happens. I'll post an update soon for better or worse..

thx all

jac113

iTrader: (4)

Update guys:
It turns out that this is one of those maybe it'll work, maybe it won't threads. So after all that i wrote about above, the seal doesn't leak and diff doesn't make any more noise. I'm still hesitant to get on it bcuz i'm not really sure how much I torqued the nut to. I torqued it 'til the diff housing started rotating, unless it was just me seeing things.

But anyway, thanks all for the input, really appreciated.

Now i'm on to the next problem
*Oil leak from somewhere, vlve cover gaskets or rear intake seal
*tranny input shaft bearing, or at least i hope
*primary cooling fan - good thing it's winter time

just to name a few... Merry Christmas!