quote:

Originally posted by olroy II:
Almost any significant drive train change, and addition of a GV is a major change, is going to change the way things sound. It's easy to get spooked by something unfamiliar.

There's also the possibility that after those gears get worn in, the noise will diminish.

If it is something of a lite nature and you have been called a "nit pick" before (I've been called that and worse) then maybe it's not as bad as you think it is. You are the judge as to what is slight so this is purely subjective.

I would still check out the driveshaft for "out of timing" and to see if there is any signs of a weight that came off. Look carefully and remember that if this turns into a vibration you should get it checked out more indepth. Try the trident tuning fork as this may only be a slight harmonic noise.

See if the Gear Vendor people will check it out themselves - they have more experience with there products. Get them to give you something in writing that says they checked it out.

Let us know what happens - good luck.

I have been installing Gear Vendors for 23 years and I can assure you that they do in fact have a slight whine in OD at about that speed. he nature of the gear sett I imagine. You should not hear the whine in direct drive. Your motorhome must be some quite to hear it though, I have only heard it on the most quiet installations. As far the driveline, 80" is 15" beyond even Gear Vendors maximum length. Correct it immediatley. Unless GV flew a tech over to Camping World, I doubt the installation was "supervised" by anyone. Have everything rechecked by someone with more GV experience. While we are at it, the maximum drivel line operating angle is 3.5 degrees and the minimum is .5 degrees. I hope this is of some help to you. Don't give up on the GV, it is a wonderful piece of equipment.

quote:

Originally posted by billyt53:
I have been installing Gear Vendors for 23 years...

Look"ee" Dave. You've got another person to add to that well rounded list of doctors, lawyers, Indian... (I'm part Cherokee)

quote:

Originally posted by billyt53:
Your motorhome must be some quite to hear it though, I have only heard it on the most quiet installations.

He's got a Barth! Nuff said

I'll add my name to the list of "expertz"

If the drive line were the cause, be it, out of balance, "U" joints clock wrong, "U" joints defective, support bearing(s) defective, bent, deflection angle wrong, the typical symptoms would be a vibration or rumble thru out the coach and very well could be at only certain speeds, but usually get worse as RPM (speed)goes higher. In your case:

The original rear support of the driveline was not changed so the deflection angle of the driveline to the rear carrier should not be off by much, it could be if the slider is ahead or behind the bearing and the input angle to the bearing was changed a lot.

As previously stated by others, I also agree that 80" is way long and unless the driveline were made larger in diameter or lightened, that is to long!

If the "whine" you are describing is of a high frequency then it is gear noise that is getting into the chassis. Whether it is the rear carrier or the GV unit hard to say with out further testing or analysis. However, because the noise wasn't there before the GV unit was installed I would think it is in fact coming from the GV unit. They do make some noise and the fact that it is only in O/D would tend to confirm that is the source of the noise.

Why is it getting into the chassis?

If the GV unit is driven thru a short driveline from the transmission rather then mounted directly to the transmission as they do in some applications then it could be that the GV unit was not mounted to the frame with enough (or any) isolation.

If the GV unit were attached directly to the transmission, the added weight might be enough to compress the rear transmission mount to the point where it is not longer able to isolate related noises. Maybe the mount wasn't replaced and it is old, hard and brittle which would contribute to noise being transfered to the chassis.

As far as noise being at a certain speed, very common, gears have a natural resonance and when the speed of the gear teeth make and brake contact with each other approach the natural resonance frequency the whine will sharply increase. The gear set is being excited with a frequency near or at its natural resonance and will continue as long as those conditions exist.

I don't think you have a serious problem (other then the drive shaft being to long) Getting rid of the whine might be difficult to do. As mentioned I would check the mounting system and the isolators first.

With my SOB, I added a ton of onise proofing and when finished it was very quiet but then I heard all kinds of noises I never heard before. I also had a whine but at and around 55 MPH, it was there before the noise proofing but seemed SOOO much louder after. Went to heavier gear lube in the diff and that would reduce it but would not eliminate it.

HTH

Amen on the rear mount. I change them just for fun on any newly acquired vehicle. Lots of reward for just a little work. Sometimes I find scary things that make it worth worthwhile.

quote:

Originally posted by bill h:
Amen on the rear mount... Lots of reward for just a little work. Sometimes I find scary things that make it...worthwhile.

Ditto, I got a 71 Chevy Nova that needed "expert transmission work". It seems that everytime you went around a right hand turn fast the car would chirp it's tires and stall out.

It was traced back to the vehicle throwing itself into reverse from the transmission sliding to the left and causing the linkage to bind & throw itself into reverse!

$200 for the Nova, labor free, parts cost for a transmission mount. I was 16 years old, first car I ever owned.

Bill NY

I never thought about the rear tranny mount, but hell yeah! That thing is subjected to so much abuse, then we add another 30 or so pounds to it with the GV??? Plus I did not pay attention to your year model, if it has a lock-up torque converter, that only amplifies the whine because the engine harmonics manifest themselves too! Yeah, I do finally have a Barth ! I grew up driving Studebaker automobiles. Our Barth is the Studebaker of the 21st century. Way ahead of it's time...

Hey to billyt53. Finally got around to measuring some things on my Gear Vendors installation. The G/V unit bolts diretly to the back of the T400 tranny. The emergency brake drum attaches directly to the rear of the G/V unit. The rear of the emergency brake drum has a yoke cast into it and therefore is half of the first universal joint. The first drive shaft is attached to the rear of the emergency brake drum via this u-joint and is attached to a second drive shaft via another u-joint. The second drive shaft then is attached to the differential. From the first u-joint to the first support bearing is 60". From the face of the back of the emergency brake drum to the first support bearing is 62". From the rear of the G/V unit to the first support bearing is 65". From the back of the t400 tranny to the first support bearing is 84". There is a support bracket at the rear of the T400 tranny that bolts directly to the top of the G/V unit towards the front of the unit. From that point to the first support bearing is 82". So you could say that from the tranny support to the first support bearing, there is an unsupported weight of 82", made up of the G/V unit, emergency brake drum, and front drive shaft. The back of the front drive shaft sticks out beyond the first support bearing about 6" or so. When they were installing the unit, they took out a short drive shaft and the first support bearing because it was right in the middle of where the G/V unit would be. I questioned the unsupported length but was told it was no problem. Sounds to me like they just didn't want to go to the extra expense of modifying the front drive shaft (which was originally the second of three drive shafts) s to accept a support bearing that would have been located somewhere aft of the emergency brake drum. Yes, the whine is still there, but now I'm more concerned about the length between the tranny support and the first support bearing. Opinions?

quote:

Originally posted by humbojb:
I questioned the unsupported length but was told it was no problem. Sounds to me like they just didn't want to go to the extra expense of modifying the front drive shaft... Yes, the whine is still there, but now I'm more concerned about the length between the tranny support and the first support bearing. Opinions?

Well, you asked! Please re-read the post from 2/22 below is a small section of the posting.

quote:

Originally posted by Bill N.Y. on 2/22/06 at 3:26pm:
My gut is telling me that your driveshaft is too long and the angle of the carrier bearing is off. You need proffesional help that no amount of typing is going to give you.

Seek out a driveshaft maker in your area and pay them to give you a recommendation. Use that info to beat the gear vendor people over the head with.

And this one from Billyt53.

quote:

Originally posted by billyt53 on 3/30/06 12:06 AM:
I have been installing Gear Vendors for 23 years and I can assure you that they do in fact have a slight whine in OD at about that speed... As far the driveline, 80" is 15" beyond even Gear Vendors maximum length. Correct it immediatley.

I wish there was more that we could tell you. I don't believe that your going to figure this out on your own. You need to keep pushing G/V and C/W until satisfaction is had. I wish there was something more we could tell you other then what has been posted.

Bill N.Y.

Bill, as you said, I asked. Where can I get some ammunition as to the maximum length of drive shafts? I am close to Knoxville, Tn., so will look for a drive shaft shop around here. Anyone know of one? Was I right to state the unsupported length as the length between the tranny support and the first carrier support bearing? Thanks again.
Jim

quote:

Originally posted by humbojb:
Where can I get some ammunition as to the maximum length of drive shafts?
Jim

I would go with Billyt53's length as he has been installing these for 23 years... If he doesn't know that 65" is the max length for the gear vendor setup then I don't know who would.

quote:

Originally posted by billyt53:
I have been installing Gear Vendors for 23 years and I can assure you that they do in fact have a slight whine in OD at about that speed... As far the driveline, 80" is 15" beyond even Gear Vendors maximum length. Correct it immediatley.

Call gear vendors and let them know your having a problem on the road. See if they can't direct you to a shop for an additional inspection. You should try to give G/V enough rope to hang themselves. If you don't do it that way you'll eat most of any repairs. Keep track off all there efforts, it will show you gave them a chance and they dropped the ball.

quote:

Originally posted by humbojb:
Where can I get some ammunition

Do it this way, now your cocked and loading up on ammo.

Another vote that the shaft is too long. My contact in the industry has retired to palaces unknown, but this SITE should tell you quite a bit about your length. Keep in mind that your driveshaft rpm is the same as your engine rpm in high gear, and is 70% of that in OD.

Also, my own engine and trans swapping adventures have shown me that careful attention to angles is critical. I have had to use wedges to tilt rear axles and raise or lower rear trans mounts to bring things right. It always paid off.

I agree with Bill N Y, bill h, and billyt53, that an overly-long driveshaft is not a Good Thing. If everything is in perfect balance and alignment, all will be well. But in the Real World, the stars do not align so well, so get GV to admit its mistake.

Another consideration is that big brake drum on the end back there. It now has a longer moment arm, so any imbalance or off-center U joint will have greater effect. Something that was not a problem earlier could be one now.

Exactly my point (though not expressed as well in detail).