Rear binding and vibrating bad

[92awddsm]

Yes because I'm able to move the wheels freely at any time. I'm going to have to count the teeth again because I think I counted 43.

If the wheels move freely at anytime, even when hot, that would eliminate both sticking calipers and failing wheel bearing.

 

[white90gsx]

Yes that what id say to. I would drive it even with the shafts on it would always move freely expect for the warped rotor.

 

[white90gsx]

Ok I counted 43. SO were good there.

 

[4pistons]

poted by 92awddsm - "Tooth count on 5spd ring and pinion should be 39/11 and the auto should be 43/13"

 

[Auto RS T]

Ok I counted 43. SO were good there.

Your car has an automatic transmission then?

 

[92awddsm]

Your car has a 5spd tranny and an automatic rear end. They have different gear ratios and is more than likely the cause of all your problems. You need to get a 5spd rear and either a tranny rebuild or a replacement tranny. If you get your tranny rebuilt, expect to pay more than the basic rebuild cost because I am positive that you have damaged other tranny parts that arent included in the rebuild.

 

[white90gsx]

How is this even possible the rear has been untouched. What the hell. I can almost guarantee that the rear has NEVER been remove because it took huge breaker bars and 3 cans on pb blaster to get those bolts off. How can people be so stupid putting the wrong parts on. I'm counting them one more time before the go looking for a new rear .

 

[4pistons]

When I bought this car the previous owner did the 4 bolt swap

You already said that he did a 4 bolt swap. It's obvious now that he did an "automatic" 4 bolt swap. At least you know where you have to start.

expect to pay more than the basic rebuild cost because I am positive that you have damaged other tranny parts

Welding the center diff will fix it and eliminate the VC, too. It's probably the cheapest way out.... unless you did break something in the trans. But if the trans seems to drive and shift fine I think it's ok.

Rick - '91 GSX

 

[white90gsx]

Well I found a member on this site that is selling me a trans...But I'm still going to need a rear. The member on this site knows the previous owner of my car and said that the car was an automatic and it was converted.

 

[4pistons]

Your trans may be ok. I'd change the rear first. If your VC is fried in the trans it's only about $75 new and easy to replace without removing the trans. It's more important that you replace the rear. Save your money for that.

Rick - '91 GSX

 

[white90gsx]

What I find funny is that how come when I was driving the car before it drove fine with no notice to the different gear ratios? Now all of a sudden I can feel it... Also I already put down $100 for the tranny he only wants $200 for it. So not a bad price.

 

[4pistons]

It may have taken a while for the VC to go bad before the symptoms showed up.

he only wants $200 for it. So not a bad price

How do you know it's any better than yours?

Rick - '91 GSX

 

[white90gsx]

Because he was just driving the car before he tore it apart and its still in the car.I know it doesn't mean that its good. But the rear in fine so it has to be the tranny.

 

[4pistons]

Just be careful. That doesn't mean the trans is good.

Rick - '91 GSX

 

[white90gsx]

Yea I know...But even after what the wise man said the tranny is probably killed after that abuse.

 

[4pistons]

Only two things could be toast if you're still driving it. The Viscous Coupling (I'd be 95% sure it's fried) or the Center Diff (maybe 60% since you said the splines aren't worn and the output shaft shaft doesn't have play in it.) If anything else was bad or broken you'd know it by driving it.

There's no guarantee that the used trans doesn't have the same problems as yours. Improper towing will damage the VC and CD the same way as your mismatched rear gears.

I'm just giving you the heads-up cause I'd hate to see you right back in the same situation after all the trouble you've gone through.

A "Wiseman" is one who learns from experience, his or others. It's not just a chat board label. No disrespect to 92awddsm!!

Rick - ' 91 GSX

 

[white90gsx]

Well so you think I should just get the rear first?

 

[white90gsx]

Well I am getting a rear and a tranny I will keep posted.

 

[viprez586]

I believe I'm going through the same problems.

Here are my symptoms:
Drained rear diff- fluid was black after ~10k mi.
Binding all the time.
Vibration during driving.
NO rear tire skip in tight circles.
A whirling/ growing on deaccel only.
Checked final backlash- almost 1/2" rotational play.

As of right now i believe it to be my pinion depth is out of spec. causing these problems and are most likely associated with the black diff fluid(black meaning overheated).

I haven't had much time to look at it so as i go through diagnosing mine i will let you know what my findings are and hopefully we can help each other out narrowing down to the real problem.

Once i rip mine out i hope to do a write up on the entire removal/tear down/inspect/rebuild process.

 

[dsmmatt28]

Are all the tires the same size?? Cause if they are not it will cause the same problem.

 

[viprez586]

Are all the tires the same size?? Cause if they are not it will cause the same problem.

Yes, I'd hope I wouldn't miss something that easy.

 

[white90gsx]

Well I have to get the rear in before I can go any further.

 

[dsmmatt28]

Yes, I'd hope I wouldn't miss something that easy.

I had the same problem took apart the tranny checked the center diff swaped viscous and replace transfer case and rear end. When the car was up in the air all wheels would spin freely when on the ground the car was so hard to push i was like what the f###. Turns out it was my tiires of all things something so simply to cause a big pain in my ass.

 

[4pistons]

Here's my thoughts and opinions....

Drained rear diff- fluid was black after ~10k mi.

A little subjective. HOW black?? Are there metal flakes in it? Engine oil turns black from combustion residues in it. The rear diff doesn't have any of that. So what's making it black?

Binding all the time.

If your pinion depth is out and there's 1/2" of play where's it binding? It ought to be clunking and loose. What's binding?

Vibration during driving.

The only things that can go bad in a rear diff are gear damage or worn bearings. Neither issue would cause vibrations. They would cause noise, like clunking and grinding, but not vibrations. Vibrations are caused from something being out of balance.

NO rear tire skip in tight circles

Rear tire skipping is an INDICATION of center diff trouble. No rear tire skipping does not mean no center diff trouble. My welded center diff does not skip when I have my fat, sticky, autocross tires on. Only my streets.

Checked final backlash- almost 1/2" rotational play.

The BACKLASH was 1/2"??? How did you measure that?
On what is there 1/2" of rotational play?? Tires? Ring Gear? Pinion Gear? Driveshaft?

A whirling/ growing on deaccel only

Read this entire post.... http://www.dsmtuners.com/forums/dri...idanza-6-puck-now-having-noise-vibration.html


DISCLAIMER: All my thoughts and opinions are based solely on the information provided and as I imagine your presentation. Consequently, an accurate internet diagnosis is nearly impossible!

Rick - '91 GSX

 

[viprez586]

Here's my thoughts and opinions....


A little subjective. HOW black?? Are there metal flakes in it? Engine oil turns black from combustion residues in it. The rear diff doesn't have any of that. So what's making it black?

The kind of black you wouldn't want to see, still transparent but not like gunk, no metal flakes. Yes i do realize black can come from irregularities but black can also indicate an overheating condition. Something in the rear binding which causes the fluid to break down and overheat and you often see the fluid change color. In the trouble shooting section of the rear axle under heat it says: insufficient gear backlash, excessive preload, insufficient oil.
This is why i highly doubt it is contaminates because my car will hold still on small hills.

If your pinion depth is out and there's 1/2" of play where's it binding? It ought to be clunking and loose. What's binding?

Measured at the DS, i looked the procedure up in the service manual. Jack up the rear of the car, put in neutral, apply parking brake. Manually turn the D.S. C.W. as far as it will go and make mating marks on the companion flange dust cover and diff. carrier. Manually turn the D.S. CCW as mar as it will go and measure the movement. (LIMIT- 5mm) EDIT** just measured and its about 1/4"-5/16" play.

The only things that can go bad in a rear diff are gear damage or worn bearings. Neither issue would cause vibrations. They would cause noise, like clunking and grinding, but not vibrations. Vibrations are caused from something being out of balance.

I read that thread and that is probably what I'm hearing. More can happen then just gear damage and bearings although those might be the final result of what breaks and THEN you notice somethings wrong. Shims can wear so your preload is gone, the spacer can wear giving you incorrect drive pinion preload backlash and a weird gear tooth pattern.

Rear tire skipping is an INDICATION of center diff trouble. No rear tire skipping does not mean no center diff trouble. My welded center diff does not skip when I have my fat, sticky, autocross tires on. Only my streets.

Just wanted to clear that up before someone asked.

The BACKLASH was 1/2"??? How did you measure that?
On what is there 1/2" of rotational play?? Tires? Ring Gear? Pinion Gear? Driveshaft?

Driveshaft - dust cover & differential carrier.

Read this entire post....

Read that, very interesting and probably the sound I'm accompanied with.

DISCLAIMER: All my thoughts and opinions are based solely on the information provided and as I imagine your presentation. Consequently, an accurate internet diagnosis is nearly impossible!

You and me both, they don't teach you in school how to diagnosis a car over the internet.
If anything they draw a wiring diagram and give you symptoms, asking for the problem.
I just like to post my problems so other people can learn from them, or maybe they can help point me in the right direction or investigate something i may have overlooked.

**UPDATE** I found my back left caliper slides frozen and holding the wheel, which explains holding on hills. This would also give a constant differential action and could cause the gear oil to breakdown.