Rear end question

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JefftheComputerMan

JefftheComputerMan

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Ok, I have a 64 valiant that has an 8.25" rear end that has been whiney for the whole time i've owned it.

The rear is a 8.25" 1974 dart with shuregrip.

After the 5.2 Magnum swap, It broke one of the carrier bolts. I discovered that the yoke nut loose and I replaced the bolt.

Now its whining bad, when at speed if you lift a little, like between acceleration and deceleration, it starts whining BAD!

It doesnt do anything bad on full accell or deceleration.

The mechanic I'm working with says the ring and pinion has to be replaced (he rebuilds big time diesel rears, so I hope he knows)

My question is Whats the best route to go? Ford 9", Mopar 8.75, Dana 60? I have the shurgrip center chunk that seems good, the 8.25" Housing, new axle bearings, Disc brakes, and BBP.

What way should I go? Rebuild current ring and pinion ($1000) or buy another rear end all set up and replace brakes, spring perches and cut length / axles ($????)
:banghead:
 
Have you rechecked the pinion nut? Once they back off, they can be problematic. Also if the pinion bearings are worn, that can cause noise. There are a few things to check before just throwing a ring and pinion at it.
 
Thats the Ring and pinion cost, I was told a bearing set and shims, plus installation added up to about $1000.
I'm trying to keep this simple, and if I went Dana 60, it would be at least new disk brakes and I have very little clearance in the fender wells.

I've seen the videos of how to align the ring and pinion and I have no tools like those. I understand the backlash is .004" and pinion depth is critical as well.

I can drop the rear end and reinstall another that is already built correctly.
 
Like RRR said, before you go crazy, pop the driveshaft off and check to make sure the pinion yoke nut is TIGHT. Same thing happened to me last year and then it let loose and made a big mess! Don't drive it until you check that nut
 
Are you exceeding the power limits of the 8-1/4?
There inexpensive to rebuild. The 8-3/4 is expensive to obtain much less rebuild.
 
Assuming everything is tight, once a gear set starts whining on the coast side, yet is quiet on the drive side; there is almost nothing you can do about it. If you adjust the pattern to get the coast side a tiny bit quieter then the drive side will begin to sing.Without the expertise and tools to mess with it yourself, you can pay a guy to make several unsuccessful adjustments. In the end you will throw those gears away.
So now what to do.
This depends an awful lot on your future plans, and power level. If you are thinking of filling up the wheelwells, then narrowing the rear is likely on your mind too. So if you are going to spend that money, then it makes sense to spend it on something that can grow with the project.
If you're not into racing, then you dont need a Dana or even an 8.75. For a streeter, with only occasional trips to the track, and a small block(non-stroker), the smaller 8.25 will serve well. And they are cheap and readily available. You can even have two or three. They take about the same time to swap around as do the chunkers.And you can roll them in,tires and all;no heavy lifting.

You gotta love the rears that you can swap pumpkins on.
 
Aren't there a few guys here running strokers and 8-1/4's?
 
rumblefish360 said:
Aren't there a few guys here running strokers and 8-1/4's?
Click to expand...

My guess is that something came loose (like the the pinion nut):) and that if not driven any more may be able to be saved.
It's going to take some pictures and some specific answers of findings to get to the bottom of it quickly.

Does the driveline move up and down or sideways at all with no load on it? (like the parking brake on with the car in neutral)

Second question: Does the the whole yoke move including the shaft behind the yoke where it goes into the rear end?

Do both these at the rear of the driveline, so just grab it yank around on it a bit and report back.
 
Will do, It's actually difficult to get it to the whining spot. It doesn't whine on accell or decell it's just in between, so I'm hoping it's the pinion nut loose.
It is when u get to a speed and let off to stay at that speed and barely press the gas. It's not a grind, its more of a vibration. Hoping you guys are right. Will get car back soon, will post pics either way.

That said, If the yoke is loose, what is the procedure to tighten it and keep it tight?
What keeps it tight? I couldn't find torque specs, so I lowered car to about half the cars weight on tires and firmly torqued yoke nut (up until tires started to spin)

Do I need to have someone stand on brakes and I hit it with Impact or is there a torque spec I can't find?
 
The reason why you cant find a torque spec for the pinion nut is that the nut is tightened only so far that the crush sleeve between the 2 pinion bearings is compressed enough to correctly preload the bearings. The preload is then measured with an in. lbs. torque wrench by putting a socket on the pinion nut & measuring the turning resistance if the pinion.
This has to be done with the diff carrier out of the axle. If the crush sleeve is compressed too far, resulting in excessive preload then then crush sleeve has to be renewed. it is not reusable.
The method I use to tighten the pinion nut is a socket on a long breaker bar while holding the pinion yoke with an equally long holding attachment, tightening the nut a tiny amount at a time until the correct preload is reached.
 
Sure. I'm at work at the moment, but I will try & dig the specs out over the weekend & post them here.
 
OK Jeff, here you go.

Pinion bearing Preload is 12 - 15 in lb with new bearings. If the bearings are used then aim for 6 - 8 in lb. Don't forget, if you overtighten the pinion yoke nut & end up with too much preload you have to change out the crush ring. The secret is to sneak up very slowly on the desired preload by tightening the pinion nut a small, & I mean small (maybe 1/4 of a flat) amount at a time.
Once the diff carrier with ring gear is back in, set your backlash at 0.006 - 0.010 using a dial indicator attached to a magnetic base. Check backlash in 3 different positions.
Then mark up 5 or 6 ring gear teeth on both sides with marking compound & check the gear contact pattern.
Hope it helped.
Cheers. Gaz
 
Kickdown explained it pretty well and I'll add a bit.
The bearings that the pinion gear rides on are a tapered roller style bearing, and the amount the nut is tightened determines how much the crush sleeve is crushed down to set the preload on those bearings.
Once that preload is set, the pinion gear itself should be back in it's correct position to mesh with the ring gear correctly (and hopefully stop the noise and vibration)
Sometimes it works out fine, and sometimes it take a replacement of the bearing and crush sleeve to start fresh.
Sometimes the gears are already toast and only replacing them will solve the problem.

That's what we need to try and determine.
 
...It's actually difficult to get it to the whining spot. It doesn't whine on accell or decell it's just in between...
Click to expand...

I think the term you're searching for is "float". I'm with Rob...check the pinion nut first. Get it fixed before it gets any worse and you can probably salvage your ring and pinion with nothing more invested than some time, diff lube, and maybe some bearings/crush sleeve/pinion nut/seal...all parts that should be available at a real parts store.
 
when u retightened the yoke/pinion nut on a crush sleeve type rear, u probably crushed the sleeve more = too much pinion bearings preload
 
Thx for the INFO!

BTW, I used to be stationed in Hessich Oldendorf back in 1987. About 100 km down E30. What a small world...
 
If the nut was loose you would have noise on decel, what you're describing is the set up is ever so slightly off, that adjustment is very very slight and then that noise will go away
 
Ok Update, I limped car home trying to stay out of the "grind zone". Drop drive shaft, pinion nut tight....
Dropped cover, magnet in bottom is covered with very fine metal sludge, a few pieces smaller than a #2 pencil tip... Scary but not horrible. After reading and viewing videos, I understand a lot more about the contraption. I look at pinion wobble, very, very little.

I take bolts out of carrier and twist wheels to and fro, TONS of slack between pinion and ring. This thing was barely touching the ring.

So I look at how things are aligned, and when I broke the bolt earlier I removed and replaced all of them. Big mistake, when I removed the bearing caps the screw parts both came out. That threw it all off, I didn't think the pumpkin was aligned by anything but the bolts.

So I basically snugged up the screw in parts to make the bearings seat in the race. But I didn't take into account how far the pumpkin had slid to the drivers side. This left a huge gap between pinion and ring.

So after about 3 hours of "centering" the chunk to just mesh with pinion, I got it to spin extremely smooth and no noise (by hand, not started it yet)

I have no slack in the bearings, pinion, or pumpkin... So wtf, I buttoned it up and will give it a spin LOL! Need more gear oil and it's late....

If I gotta redo the rear, might as well break this one real good! LOL Who knows it may last the rest of summer, MAYBE MORE? Will post pics of the tiger stripe on the carrier where the pinion nut loosened and ground stripes into the carrier!

Hell ain't this called hotrodding? In the computer world it's call Plug and Pray!

Thanks, all for your advice, U were dead on SuperShafts!

I wish 5 or 10 of yall lived near me, but Yall would probably move away! LOL

I'll post pics later, I don't want to jinx it. Mechanically, its functional, numerically its horrible, but wtf I will need to replace it anyway, so I may get some fun out of it this year.
 
Tiger Stripes! Look at the wear on those ring teeth, like a crack addict!
 

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Yep. Seen a few like that. R&P gotta go. I dont think I would risk any serious driving with that thing, especially if my family are riding with me. That must have made 1 heck of a noise grinding away in there.
 
KickDown said:
Yep. Seen a few like that. R&P gotta go. I dont think I would risk any serious driving with that thing, especially if my family are riding with me. That must have made 1 heck of a noise grinding away in there.
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Kickdown is completely right Its gotta go dude. No need to make even worse than it already is And thats badd dude
 
I'm just running around town it it, by myself, and it's whining about what it was when I got it. (not much, but u can hear it)

Anyone have a short list of bolt in rears? I don't wanna go through the r&p expense if I can replace the whole thing for less time and effort.

I've looked at Ford 9" but that requires cutting, welding and axle re spline. Way too much time, and yall all know how crazy the 8.75" stuff is, if u can find one its gonna run 2 grand to get going.

This car is just a toy, i'm not putting 20 grand in a Barracuda here. Hell I gotta pay Barracuda prices for a Valiant!

It's a bone stock 99 Durango engine with 44k miles on it, and i'm not looking to upgrade that till it breaks. Just love to drive it at all right now!
 
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