Whining noise from rear

[jdbs3]

1990 Vanagon, original transmission, ~140K miles

Just had the rear wheel bearing replaced by my independent (VW knowledgeable) mechanic. With the axles removed, he also cleaned the CV joints, and replaced the transmission drive flange seals that were leaking and the drive flange cap seal. He also topped off the transmission fluid.

Now (possibly coincidentally) I am hearing a steady whining noise coming from the rear of the van. I think it is present in all gears, but best heard once the van is cruising in 4th gear.

I had my mechanic listen to it. He felt it was coming from the gear box and was the differential bearings. He also noted that this was a typical sound for van transmissions as they age, and that it was not a problem or sign that the transmission was going bad.

However, I don't recall ever hearing this type of noise on either my original 1984 water box, and, prior to the wheel bearing work, this one.

I realize you can't diagnose a sound from this write-up, but assume it is a noise coming from the gear box, do you agree with my mechanics comments?

Is there possibly something else I should have him check out?

Not much to go on, but hopefully someone will have some insight into this.

Thanks

[raoul mitgong]

Do you have kids?
-d
_________________
84 Westy with a 2.1 (Groover)
86 Tintop Syncro (Crow)
86 Tintop Syncro to Westy project (Tom Servo)
91 Westy (Only the top 12 inches of this van (a burn victim))

[jberger]

It is possible that your mechanic did not reinstall the differential carrier bearing adjusters correctly when he replaced the seals. That would definitely change the preload and backlash of the pinion\ring gears.. Perhaps ask him to recount how he removed and reinstalled these.

[insyncro]

A worn ring and pinion will make that sound under load and lessen with your foot off the pedal.

R&Ps are one of the most expensive parts of the transmission.

Noise means it is time to start saving for a rebuild with new parts.

[Zeitgeist 13]

Pinion bearing
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'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
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y u rune klassik?

[jdbs3]

Thanks for the input. An update …

Manual transmission.

It is more like a whirling (rotational) sound, only heard when the van is in motion, and best heard after the van is at cursing speed (4th gear).

While cruising and I put the van in neutral, the noise is still there.

It increases in pitch with speed, and decreases in pitch when slowing down.

[danfromsyr]

my brother once told me he had an odd noise only on turns leaving my house late one night.
when he got to his place my cat popped it's head up behind the back seat.
he drove it back, I told him he coulda kept her the night..

[jberger]

[jdbs3]

jberger,

[jberger]

There would be no external way to verify that it was corrected, or if that is even the problem. Only the shop\tech knows how he did the repair. In order to change the inner and outer seals on the adjuster, they have to be removed. If I was doing this job I would use a chisel to mark both the magnesium case and the aluminum adjuster. I would also use a depth micrometer to measure the inset of the adjuster and scribe it on the aluminum as well. This way I can visually verify that my marks line up and on the proper revolution. It is a fairly easy task.. unless you don't measure and mark first.

[Sodo]

[jdbs3]

An update …

I had watch my mechanic do all of this work; I’ve a good recall of what was done, but, not being a mechanic, don’t necessarily know all the part names, etc. that were touched/replaced. But with the part numbers, Bentley and another diagram on getvwparts.com, I was able to recall and see what was replaced.

I also stopped by to talk with my mechanic this afternoon. He noted that he did not take out or move the differential carrier bearing adjuster rings. One of them moved slightly when installing parts. He readjusted it based on the existing dirt marks. Looking at Bentley, I agree, he did not touch the adjusting rings.

The 2 parts that were replaced replaced were:

- 091 301 189 - Drive Axle Flange Seal that seals the drive axle flange on the transaxle. Looking at Bentley and a diagram on getvwparts.com, this is the seal that sits between the untouched adjusting ring and the lock ring for the adjuster, aka drive axle flange plastic cover, part #: 091 301 197.

- 002 517 289A Drive Axle Flange Cap

So it was not the adjusters that caused this problem.

Possibly insyncro is correct - a worn ring and pinion. It is just strange that the day before the shop work, there was no noise; the day after there is the whirring noise. Arg! I’m open to any other theories on the timing of this noise.

The plan going forward is to:

1. Change the transmission fluid with Redline MT 90; check for containments in the old fluid. The last time it was changed was in Nov-02 at about 98K miles, or ~40K miles ago (a best guess estimate).

2. While the van is up on the lift, check to see if there is any excessive play in the bearings behind the drive flange.

If the noise is still there, then since it is coincident with the turning of the wheels, and not the gear shaft, my mechanic said it would be either the pinion bearing or carrier bearing. While there is no way of knowing which, nor how long it will last, my mechanic felt it could be as much as another 30 – 40K miles. Given my yearly driving, that could be another 10 years.

A few questions:

- Is Redline MT-90 75W90 GL-4 the best synthetic to use?

- Any comments or questions on my update? Or any other theories on the timing of this noise?

- Any other suggestions on what I should have my mechanic do? I like to be as knowledgeable as I can when I have work done on the van.

Thanks

btw - My mechanic has worked on VW's, since at least 1993; he worked for a number of years at a VW dealership before starting his own business working on VWs, etc. I've watched every bit of work he has done on the van in the last 11 years. He is a very competent mechanic and very thorough in his approach.

Sodo, jberger, I'd be interested in your comments after reading this update.

thanks

[insyncro]

You can inspect the R&P by removing the bellhousing...OR if you have a digital boroscope you can drain the fluid and snake it up into the area behind the bellhousing without removing it.

Removing the bhousing gives a much better view, but if the R&P is bad, it will show it to a trained eye.

Just trying to help.
I know most don't have fancy tools.

Others have pointed the finger at bearings.
They could also be a problem.

Bottom line, opening up the trans will be the best bet to explore it further and than remedy what is found.

Sorry for the not so great news, again, trying to help the situation.

[jberger]

[insyncro]

[Sodo]

[jdbs3]

Thank you again to all for your excellent feedback. Hopefully, others can benefit from this ongoing dialogue. And apologies for the length of my reply. I’m trying to assure I provide as much information as possible.

I’ve spent the last few days reading Bentley, reading notes files, and watching youtube, trying to learn as much as I can. Please correct me if any of the following is incorrect or makes no sense.

Thanks!