Rear end approaching it's demise

[DrewQ45]

How's everyone keeping? Been a while since I posted in the Q forum. I see big things are happening all over. You guys never cease to amaze me. Turbos and all....

My rear end has developed a whine for a few months now...it has grown progressively louder as the miles rack up. At 60mph, it sounds like a muted air raid siren emitting one long tone and is loudest when I remove my foot from the gas.

Today I ran the car on jackstands and my ears were ringing when I crawled out from under it. I pulled the fill plug to make sure it has enough fluid and it does... I changed to full syn about a year or two ago. Guess it was too little too late with 227K on the clock and all. I'm gonna pick up one from the JY soon but wondering which year is best. I'm not sure if 94 plus will have a different gear ratio. Also noticed from a recent post that the cooling fins are gone on the later models. I'm not really interested in 4.08 swop as I don't feel like the results are worth the trouble.

Sooo... for all those who have swopped theirs...

Should I just stick with 90-93?Is it possible to pull without removing exhaust? (looks like It might come out with some manuevering... Part of my exhaust is welded in so only way to remove is to cut it out.)If I cut the exhaust, I'm going to just go with straight pipes

..Drew..

[qship96]

The real challenge you face is that you wont know if the one you pick from the boneyard is much better than yours until you pay for and install it.Sure would suck to go thru all that and end up with another noisy one.

[DrewQ45]

The real challenge you face is that you wont know if the one you pick from the boneyard is much better than yours until you pay for and install it.Sure would suck to go thru all that and end up with another noisy one.

New is not an option unfortunately. I'll buy one with warranty.

[sijoko]

How's everyone keeping? Been a while since I posted in the Q forum. I see big things are happening all over. You guys never cease to amaze me. Turbos and all....

My rear end has developed a whine for a few months now...it has grown progressively louder as the miles rack up. At 60mph, it sounds like a muted air raid siren emitting one long tone and is loudest when I remove my foot from the gas.

Today I ran the car on jackstands and my ears were ringing when I crawled out from under it. I pulled the fill plug to make sure it has enough fluid and it does... I changed to full syn about a year or two ago. Guess it was too little too late with 227K on the clock and all. I'm gonna pick up one from the JY soon but wondering which year is best. I'm not sure if 94 plus will have a different gear ratio. Also noticed from a recent post that the cooling fins are gone on the later models. I'm not really interested in 4.08 swop as I don't feel like the results are worth the trouble.

Sooo... for all those who have swopped theirs...

Should I just stick with 90-93?Is it possible to pull without removing exhaust? (looks like It might come out with some manuevering... Part of my exhaust is welded in so only way to remove is to cut it out.)If I cut the exhaust, I'm going to just go with straight pipes

..Drew..

I had the same problem with my 95 Q Touring. I was in Atlanta at the time and got one from a yard that said it had only 85k miles. I was overjoyed to find one with such low miles. Well, I went thru an ordeal to change it out in my Mom's garage. I had to head back up to NY for classes and got everything done the night before I had to leave.

It should have been time of satisfaction. Instead, problems. The first thing was the TCS light was on. I couldn't figure out why. I double checked all my connections. Everything was good. Finally, I looked at the reluctor gear on the two diffs and I noticed the problem. The one from the JY was from an older Q and the reluctor gear teeth count was different than the one from my 95 Q. So that was bad.

What was even worse was the whining coming from the so-called "low mileage" diff. It was just as bad as the one that came out. I was pissed but I couldn't do anything since I had to leave the next days for my long journey.

So what am I trying to say? If you can get a true "low mileage" unit, go for it. Make sure the ABS reluctor ring pattern matches your current unit.

If you can find a place to rebuild your diff and replace all the bearings and chech the lash, that's the best solution. I recommend UNITRAX since they have done a lot of work on R200 diffs.

[Q45tech]

227k was just the mileage back in 2002 when mine was replaced.

Important to actually visit the carcass and see for yourself the odometer or buy a new $2750 unit from Infiniti.

[lino]

Hey Drew, nice to see you around.

Here's some reading about differentials if you're interested:

http://www.metricmechanic.com/...s.pdf

http://www.horsepowerfreaks.co...300zx

[DrewQ45]

227k was just the mileage back in 2002 when mine was replaced.

Important to actually visit the carcass and see for yourself the odometer or buy a new $2750 unit from Infiniti.

Thanks to all for the advice so far...

I'm sure that the years spent driving with an inbalanced driveshaft helped to do in the diff. I came across a 90' with 110K on the odo. The interior was nice enough to steal the passenger seat and transfer cushions to the driver's.... which I'm in the middle of doing. I'll be pulling the diff out in short order. With the type of mileage on the car, I'm not spending $2750 on anything...too much can break at this point to replace everything with new.

Has anyone pulled out the rear end without messing with the exhaust? Let me know.

Thx.

[lino]

Be sure to share pics of interior seat swap if possible.

Thanks.

[AlabamaDan]

Jeff Williams and I pulled a rear end at the junkyard. The cats had already been cut out so removing the exhaust wasn't a problem, so we did. I can't say if it would be possible to do so without removing it or not. You could drop it down loose all the way and I'd expect that to give you enough leeway.

[3Q Jay]

to your original question, the ratios did not change from 90-96.

you will want a non-tcs unit (one abs sensor on input shaft, vs. 1 on each output shaft).

my 94 (July 1993 build) has the fins,and the 95 (Nov 1994 build) does not.

they are both actives. go figure.

[Denver90Q]

I wonder if anyone rebuilds these to OEM standards?

[Q45tech]

One of our techs spent 8 real hours [all day] rebuilding one. Getting the parts made this a $1450 exercise. Plus removal and install labor!

Unfortunately Bobby became the Master Tech at Troncalli [now Nalley Decatur] years ago.

I'm sure you could arrange for them to do for $2,000+

The warranty is the rub, I'm sure they wiuld recommend a new unit.

[maxnix]

Hence the price of the new unit is not that unreasonable, especially with the dollar sinking faster than the Titanic.
Modified by maxnix at 10:10 AM 2/29/2008

[Q45tech]

Hopefully members see how 2 cents per component [suspension, diff, transmission, etc tire.brake combo ] per mile adds up to 15 cents per mile fast.

Yet they ignore these PENTUP COSTS until something actually breaks.

I guess it is hard to think and cost estimate in the future to really understand cost to own and drive and maintain.

Insurance should be paid quarterly by miles driven [miles exposed].

[DrewQ45]

One of our techs spent 8 real hours [all day] rebuilding one. Getting the parts made this a $1450 exercise. Plus removal and install labor!

Unfortunately Bobby became the Master Tech at Troncalli [now Nalley Decatur] years ago.

I'm sure you could arrange for them to do for $2,000+

The warranty is the rub, I'm sure they wiuld recommend a new unit.

Granted, my car is realiable but I won't be throwing 2K at it at this point. I'm going to try for a relatively low mileage used diff and install it myself. Hard to justify spending the cars entire value on a diff...especially when I have tools, ability and access to parts.

[bullittandy]

Not sure how much is different between the 97+ and earlier models but it took me about 2 hours to pull the differential out of my 97 parts car.

I thought it was pretty easy, the hardest part was getting out from under the car to put the transmission into nuetral, in the driveshaft and get back under the car.

I didn't remove the exhaust on this car but again it was a 97. I needed a breaker bar on two of the drive shaft bolts.

There would be no reason to buy new on your car, clearly you're clever mechanically and as long as you're willing to cinsider your labor "free" then there's no harm in taking a chance on used units.

BTW, where are you getting parts? I'm often at the Pull a Part off Moreland and they ALWAYS have at least 3 early Q's. I've only seen a 97+ once and it was picked clean.

[DrewQ45]

Not sure how much is different between the 97+ and earlier models but it took me about 2 hours to pull the differential out of my 97 parts car.

I thought it was pretty easy, the hardest part was getting out from under the car to put the transmission into nuetral, in the driveshaft and get back under the car.

I didn't remove the exhaust on this car but again it was a 97. I needed a breaker bar on two of the drive shaft bolts.

There would be no reason to buy new on your car, clearly you're clever mechanically and as long as you're willing to cinsider your labor "free" then there's no harm in taking a chance on used units.

BTW, where are you getting parts? I'm often at the Pull a Part off Moreland and they ALWAYS have at least 3 early Q's. I've only seen a 97+ once and it was picked clean.

I was gonna try the Junkyard but I've a got a Mechanic buddy of mine over in Snellville who has a few Qs sitting. One is a low-mileage 91' with front end damage so I might pull it off that. My labor is always free for me. ...The way I look at it, time spent working on the Q could be time spent in front of the TV or lazing around... only much more productive. I've pulled the driveshaft many times and the bolts on the flanges look like they can all be accessed easily. Hardest part will be exhaust which is welded where it should have been clamped by a U-bolt. I've already purchased a cutting disc for my drill. Since I was already considering getting rid of the rear muffler for straight pipes, it'll be the perfect excuse!
Modified by DrewQ45 at 11:52 AM 3/2/2008