Another noise thread by a newbie....:)

[berger]

Hey Guys.

Happy Victoria Day Weekend!

I wanted to reply on the thread, viewtopic.php?f=4&t=4807&hilit=noise+whine...but it was locked...

I have read as much as I can about gear whine etc, and I am used to that, but there is an occasional noise that pops up in 5th gear and at speeds of 90-100KPH. It is not present in any other gear or below those speeds. This noise has been around since I drove the truck home from Pinzgauer Canada, but it seems to be occurring more often (possibly because it is being driven). It is hard to describe, but the first thing that came to my mind was landing gear coming down and tires hitting the tarmac, but sustained...then drops off, then returns. When it first occurs, and I let off on the gas, it goes away, then returns intermittently with acceleration. I have changed all the oil in the wheels, tranny, T-case, front diff, except for the rear diff, as the plug is almost stripped. I am leaking in the rear wheel drives, and it may have been low. The noise isn't screeching, and it only annoys me in that I want to know what it is.

I have read about the clutch and throwout bearings, but I haven't tested depressing the clutch at speed to see if it goes away yet. Any ideas? Is it normal? It does seem to come from the rear, but that is hard to nail down in a Pinz.

[4x4Pinz]

while maintaining a set speed (at which the noise is occurring) and driving on a straight line, have you engaged you transfer case (green lever). Does the noise go away when you do this?

[berger]

while maintaining a set speed (at which the noise is occurring) and driving on a straight line, have you engaged you transfer case (green lever). Does the noise go away when you do this?

No, I never tried that. I was concerned about throwing it into 4x4 while at 55mph. I will give that a shot.

[4x4Pinz]

It is just a way to eliminate a drive train noise that is common in the Pinz. It is not recommended you do it for long periods of time but it as long as you are traveling straight it should not put any undo strain on the drive system.

[undysworld]

I believe the process of engaging the front axle while driving is used to determine if the truck has an out-of-balance internal front axle drive shaft. I've only experienced this on one truck, and mine doesn't do it (perhaps due to the shorter internal shaft on a 712). It was a vibration at higher speeds, but I don't recall that it was particularly noisy.

There can be a fair amount of gear whine from a Pinz though. It likely gets worse as things wear with age.

But if you are concerned about noise from the rear, and you haven't checked the fluids there, I'm not sure that I'd be doing much (any) driving. If you have leaks from the differential into the wheel drive units, you may well be running low on diff lube. While repairing such leaks requires removal and splitting of the differential, it's cheaper than simply replacing the differential in case you destroy it. Either way requires removal and reinstallation of the diff.

If you haven't even tried to engage the clutch when this problem is occurring to see if the noise changes, why not? Especially if you are wondering about the throw-out bearing. Without even knowing whether it has any effect on your noise, you're sort of asking us to just guess.

A little more effort and info from your end might help others to help you better.

[berger]

I believe the process of engaging the front axle while driving is used to determine if the truck has an out-of-balance internal front axle drive shaft. I've only experienced this on one truck, and mine doesn't do it (perhaps due to the shorter internal shaft on a 712). It was a vibration at higher speeds, but I don't recall that it was particularly noisy.

There can be a fair amount of gear whine from a Pinz though. It likely gets worse as things wear with age.

But if you are concerned about noise from the rear, and you haven't checked the fluids there, I'm not sure that I'd be doing much (any) driving. If you have leaks from the differential into the wheel drive units, you may well be running low on diff lube. While repairing such leaks requires removal and splitting of the differential, it's cheaper than simply replacing the differential in case you destroy it. Either way requires removal and reinstallation of the diff.

If you haven't even tried to engage the clutch when this problem is occurring to see if the noise changes, why not? Especially if you are wondering about the throw-out bearing. Without even knowing whether it has any effect on your noise, you're sort of asking us to just guess.

A little more effort and info from your end might help others to help you better.

Ya, I don't get vibration at all from the drive shaft...or nothing an old truck wouldn't deliver anyway or I can feel. I don't believe I have serious leaks from the diff into the wheel drives (I do see a discoloured boot though), as the fluid isn't overflowing in the wheel drives, and I am checking the leaks after every drive. Not a whole lot of loss, just enough to get my rims a little slick.

I haven't engaged the clutch yet because I didn't think it was related, and I am not sure it is. I am just guessing after reading a few posts here and elsewhere...after I returned home from hearing the sustained noise and starting this thread. I will definitely try that, and few suggestions people have made offline. Without anyone "in the know" here to listen to what I am hearing, it is all guess work anyway, isn't it? Offering suggestions, reading old posts, and investigating based on aid other owners provide.
The noises in a Pinz can be daunting, but I ride a Russian motorcycle, so I am used to that.

Effort? I think I have put quite a lot of effort going over this truck and finding things the "experts" at Pinzgauer Canada didn't find . I know that isn't a popular sentiment with some here, but it is what it is.

[undysworld]

Effort?

I haven't tested depressing the clutch at speed to see if it goes away yet.

I guess what I meant by "effort" was, if you are even wondering if depressing the clutch makes it go away, then go for a drive and depress the clutch and then let us know what happened, if you still have questions about it. That gives us info we might be able to use in suggesting things to try.

I don't believe I have serious leaks from the diff

I have changed all the oil ... ...except for the rear diff, as the plug is almost stripped.

It does seem to come from the rear

This all concerns me, if you don't really know whether you've got fluid in the rear diff. Some small leakage into a boot is not a big deal, but losing all your diff fluid into your wheel drives would be. If the diff is empty, then you won't be seeing leakage into the wheel drives. If the noise is really coming from the rear end, the rear diff is the first thing I'd be attending to. If the plug is almost stripped, then it needs to be removed and replaced with a new plug. By the way, which of the three rear differential plugs is stripped: the drain, the fill, or the check plug? If it's just the fill plug, can you open the check plug and at least look in there?

The less clues you give, the more it's all just guesswork on anybody else's part. These trucks do seem to get noisier as the gear train wears, for whatever reason/s. They are noisy, at a minimum, even when they are working right. I don't know how far you are from the "experts" at Pinz Canada, but have you discussed things with them at all? They might have some suggestions for you. (?)

[Jimm391730]

Get a cheap 3/8" to 1/2" socket adapter, grind the end flat (so that it has very square edges on the end), and hammer it into the bunged up plug; then use a 1/2" breaker bar to unscrew the plug. Check oil level. Replace with a new plug (get a spare or two while you are at it).

[krick3tt]

Oh yeah...get new copper washers too.

[berger]

This all concerns me, if you don't really know whether you've got fluid in the rear diff. Some small leakage into a boot is not a big deal, but losing all your diff fluid into your wheel drives would be. If the diff is empty, then you won't be seeing leakage into the wheel drives. If the noise is really coming from the rear end, the rear diff is the first thing I'd be attending to. If the plug is almost stripped, then it needs to be removed and replaced with a new plug. By the way, which of the three rear differential plugs is stripped: the drain, the fill, or the check plug? If it's just the fill plug, can you open the check plug and at least look in there?

The less clues you give, the more it's all just guesswork on anybody else's part. These trucks do seem to get noisier as the gear train wears, for whatever reason/s. They are noisy, at a minimum, even when they are working right. I don't know how far you are from the "experts" at Pinz Canada, but have you discussed things with them at all? They might have some suggestions for you. (?)

If I go by the front diff, which does have a slight leak into a boot, it still had its fluid, so I am assuming the rear is still full. I know, don't assume.... . The drain plug is the one buggered. I did get the other two open, and I felt fluid when I inserted my finger into the check hole, but I cannot confirm it is full. I am going to try a 11MM hex because the 10mm won't fit and I don't want to round it out. I am going to order some replacements shortly...and some copper crush washers.

Since I don't have much faith in Pinzgauer Canada at this point, and I know I am going to have to do all the work myself anyway, I figured I would keep bugging you guys...

[berger]

Get a cheap 3/8" to 1/2" socket adapter, grind the end flat (so that it has very square edges on the end), and hammer it into the bunged up plug; then use a 1/2" breaker bar to unscrew the plug. Check oil level. Replace with a new plug (get a spare or two while you are at it).

Excellent idea!

[berger]

I took the truck into work today so that I could diagnose the noise and try out everyone's suggestions.....no noise . My drive in covers secondary roads where I can hit 100KPH. The only change I made was to drain and replenish the fluid in the rear wheel drives. I only did this because I went through some water and I wanted to check any ingestion and the level. Now, when I first heard this noise (driving home from PC) I never had a leak in the wheel drives, so I am not sure that is it. Perhaps it only appears after sustained plus 95KPH driving....

[berger]

Again...trip into work and no repeat of noise. I have also noticed that my rear leaks have stopped, as I was told they might. I know the seals will still need to be replaced, but I at least I am not slinging oil.

[Haf-e]

Or its now completely out of oil...

Checking the level is a pretty quick project - you should do it before any more driving.

[berger]

Or its now completely out of oil...

Checking the level is a pretty quick project - you should do it before any more driving.

I am, and it is fine. I keep the ratchet ready to go in my glove compartment... Even when it was leaking, it only ever dripped an eighth of the oil before it seemed to stop.