Problem Found, or Created During DS Install

[91Notch]

All gears are going to have a little acceptable whine at certain speed and certain gears. These cars I have seen tend to be heard more than others. It all depends on how much sound deadning material the manufacture uses in the vehicle. Just another little bit more information cause I have seen the gear whine issue come up in the last couple posts.

 

[MrClean]

All gears are going to have a little acceptable whine at certain speed and certain gears. These cars I have seen tend to be heard more than others. It all depends on how much sound deadning material the manufacture uses in the vehicle. Just another little bit more information cause I have seen the gear whine issue come up in the last couple posts.

Thanks, that's what I thought. Again, welcome to the board!

 

[spyder7724]

Thanks, that's what I thought. Again, welcome to the board!

I've been told by the FRPP reps that the production cars use a special lapping process on the gears to help with noise and harmonics. I just wonder if thats done on the drive and coast sides of the teeth or just the drive side.
That would explain why theres no problem when loaded and only happens when coasting.
when I install gears I always check both patterns(drive and coast) to make sure they both fall within the acceptable range along with pinion preload/depth and backlash checks at different ring gear positions. I found that on my car the backlash would change as the ring gear was rotated. It did this with 3 sets of gears and there was no runout so I know the ring gear was seated on the carrier properly so it must be the position of the ring gear on the carrier which would mean a machining error from Fomoco.
found this and thought it was neat and it explains it in a really simple way.
http://www.drivetrain.com/ringpinioninstal.html

 

[MrClean]

Thanks Ron, that was a great post! Do you (or anyone else) happen to know what rear end the GT500 runs? Maybe an OEM GT500 axle/rear end might be a cheaper alternative to a Currie 9"...or maybe the price difference wouldn't warrant not going with the Currie...

 

[spyder7724]

Thanks Ron, that was a great post! Do you (or anyone else) happen to know what rear end the GT500 runs? Maybe an OEM GT500 axle/rear end might be a cheaper alternative to a Currie 9"...or maybe the price difference wouldn't warrant not going with the Currie...

far as i know it's an 8.8 with the same type traction lock differential as our cars but it may have the carbon clutches like the 03-04 cobra's had other than that probably no changes.
I haven't had one here to check out yet so I can't say for sure.

 

[Johnmichael]

Doing some research on other owners having similar issues, I came across some interesting quotes:

I would have the run-out (not the backlash)checked on the gear while its bolted to the carrier...should be .004 or less. I think there is an issue with the latest batch of traction loks being out of round.....

Spyder alluded to this possibility.

You should check the pattern AND the backlash any time the carrier is removed and replaced for any reason. In the case of a known problem child unit, you should check it before tearing it apart as part of a thorough analysis. It is too easy for the techs to fall into the habit of simply removing the carrier and pinion, use the original shims in the original locations, throw it back together and forget it. In many cases you can get by with this. That is why they start shortcutting and not checking backlash and pattern. I have gotten in a hurry getting ready for a Saturday night and done this before myself, but ONLY on my OWN car, not someone else's.

I have said all this before and maybe even on this thread. If it comes apart, pattern and backlash should be checked, PERIOD. Not checking them is cheating the customer, PERIOD. There are many certified techs that do less than satisfactory work. I am certified in all sections with a Master certification, and certification is fine, but common sense and more importantly the desire to do a good job is the most important thing.

To the best of my recollection, I don't believe Dave checked the pattern on the reinstall. I do not know if he checked it the first time, but according to this quote, it should be rechecked when the carrier came out the second time.

Being a lincoln mercury tech i find this thread disturbing. I don't work on mustangs but i do rebuild rears on all the 8.8 lincoln mercurys.They all have the same whine that mustangs have with the exception that every 1 we rebuild works out fine. I'm thinking the problem is with the gear sets you might be using. We only use ford oem gears which requires a special pinion depth tool for only ford oem gears.

I thought this one was interesting since the gears I supplied Dave with were OEM 3.73 gears, and unfortunately, I did not see him check the pinion depth on the second install.

I've finally gotten to the point that I'm happy with my car again. It's been a LONG and frustrating struggle...The vibe that appeared after one of the gear fixes is finally gone after 3 different driveshaft replacements. The hum turned out to be mostly tire noise from uneven tire wear, which was caused apparently by a defective drivers side rear axle. They put microphones near each wheel somehow to figure that out. Replaced the axle, and boom - the woob woob sound was greatly reduced (although not eliminated)

I added this one because it (defective axle) may be the cause of the minor vibe I had prior to the gear install.

Looking back, I wish I had taken care of the minor vibe before taking the car to Dave. I also wish that Dave would have undertaken all of the recommended procedures/measurements the first time, so he and I would not have this extra work/expense, or be looking at his workmanship as the cause of the extra vibration.

 

[MrClean]

That's an interesting post my friend: last night I jacked the car up on the rear side jack points, using 2 floor jacks, to where the tires just cam,e off the ground (I wanted to unload the suspension and axle) and got underneath, then I had my wife hold on to the spokes of the wheels, and lift/realease, lift/realease, etc. Well, there's a little play in there. The wheel/axle (not the axle housing, mind you) have a minute amount of vertical (and obviously also front to back) play. In addition, holding on to the spokes and pushing in/pulling out also revealed about the same amount of play.

Could this be the source of the hum? Note that under load in 4rth (positive or negative), my hum is not noticeable, but in neutral it is....maybe under load the axle is being pushed fwd/or backwards and therefore the vibration isn't present, but w/o the load, it is free to play...to vibrate. In 5th gear the hum is there under load (this is all at 105 and higher). This is the more likely scenario.

However, if the rear end isn't the source, the other less likely alternative I've thought about is that under load the DS is stressed/torqued and therefore more rigid or less likely to bow, than when rotating at 5000 rpm w/o load.

Questions:

Ron, do you have the data for what the critical speed is for the Spydershaft?

Johnmichael, the one quote where the person changed out 3 driveshafts is unclear...was the problem the DS or the rear end? What DS' did he swap out?

 

[Johnmichael]

Marc, here's the link to the thread: http://www.mustangforums.com/m_2020118/mpage_1/key_/tm.htm

 

[spyder7724]

That's an interesting post my friend: last night I jacked the car up on the rear side jack points, using 2 floor jacks, to where the tires just cam,e off the ground (I wanted to unload the suspension and axle) and got underneath, then I had my wife hold on to the spokes of the wheels, and lift/realease, lift/realease, etc. Well, there's a little play in there. The wheel/axle (not the axle housing, mind you) have a minute amount of vertical (and obviously also front to back) play. In addition, holding on to the spokes and pushing in/pulling out also revealed about the same amount of play.

Could this be the source of the hum? Note that under load in 4rth (positive or negative), my hum is not noticeable, but in neutral it is....maybe under load the axle is being pushed fwd/or backwards and therefore the vibration isn't present, but w/o the load, it is free to play...to vibrate. In 5th gear the hum is there under load (this is all at 105 and higher). This is the more likely scenario.

However, if the rear end isn't the source, the other less likely alternative I've thought about is that under load the DS is stressed/torqued and therefore more rigid or less likely to bow, than when rotating at 5000 rpm w/o load.

Questions:

Ron, do you have the data for what the critical speed is for the Spydershaft?

Johnmichael, the one quote where the person changed out 3 driveshafts is unclear...was the problem the DS or the rear end? What DS' did he swap out?

I'll try to get that info from dana spicer(they are the oem supplier for ford). soon they are going to be manufacturing the shafts to my specs using all the same components so i'll have access to all the design and engineering info from them. Ford is running out of new cores so I'm going to have to make a very large investment and get really serious so I can sell the things in the hundreds to places like summit and jegs.

 

[Buzzystang]

In addition, holding on to the spokes and pushing in/pulling out also revealed about the same amount of play.

Could this be the source of the hum?

Dammit Clean would you quit copying me? I noticed this on my last self tire rotation (two weeks ago) - part of the reason I'm demodding and going into the dealer next month. Just want it looked at and make sure it's okay in there. I noticed about an 1/8" horizontal play when pulling in/out on the rear axles, both sides. Wonder if that's normal for an LSD? Didn't notice any vertical play...

I'm going to have to make a very large investment and get really serious so I can sell the things in the hundreds to places like summit and jegs.

What's the price point looking like??? :greed:

 

[MrClean]

I'll try to get that info from dana spicer(they are the oem supplier for ford). soon they are going to be manufacturing the shafts to my specs using all the same components so i'll have access to all the design and engineering info from them. Ford is running out of new cores so I'm going to have to make a very large investment and get really serious so I can sell the things in the hundreds to places like summit and jegs.

Dude, I'm genuinely excited for you!

Will they be exactly that same as they are now, or different? Will they still use a different than OEM pinion flange?

 

[MrClean]

Dammit Clean would you quit copying me? I noticed this on my last self tire rotation (two weeks ago) - part of the reason I'm demodding and going into the dealer next month. Just want it looked at and make sure it's okay in there. I noticed about an 1/8" horizontal play when pulling in/out on the rear axles, both sides. Wonder if that's normal for an LSD? Didn't notice any vertical play...

Let me know how it goes...I kinda think the play is just something we'll have to live with...but if I'm wrong and you get the axle/rear end replaced, or something...I wanna know. I myself already told the service mgr about the Pyder so I'm not gonna bother going back to stock/OEM rear sway bar, panhard rod, UCA or DS...but when I take it to him I'll show him how the PF and TF are parallel, just so he understands the install isn't the problem. This guys warranty philosophy is that if the part you installed breaks another part, that 2nd part isn't covered, but if there's no evidence that the mod caused the failure, then the mod didn't cause the failure....in any case, let me know how it goes please, Buzzystang

 

[Johnmichael]

Dave, I found a possible reason for the loss of preload. See underlined:

Preload Shim Design: Clean the shims completely so that there are no particles that may cause a false preload reading or cause the shim stack to change thickness over time as the vehicle is driven. Slide the shim pack over the pinion shaft to the shelf. Use the original shims on the first assembly or add 0.003" to the original preload shims to make up for the bearings settling into the housing. Tighten the pinion nut to approximately 250 (EDIT: 150) foot pounds. Go slowly so as not to damage the bearing if the preload shim stack is not thick enough. Use an inch-pound torque wrench to check the preload. If the preload is too loose then remove shims so that the bearings will be tighter against the races and increase the preload. If the preload is too tight then remove the pinion gear and add shims so that the bearings will not be as tight against the races.

This is why it took you so much torquing on the pinion nut to get to the desired preload of 20in/lbs (I read it should be 25 actually). Instead of over torquing the pinion nut to reach the desired preload, you should have removed a shim(s) to reach the desired preload.

Please let me know your thoughts on this. Thanks.

 

[91Notch]

To the best of my recollection, I don't believe Dave checked the pattern on the reinstall. I do not know if he checked it the first time, but according to this quote, it should be rechecked when the carrier came out the second time.

I thought this one was interesting since the gears I supplied Dave with were OEM 3.73 gears, and unfortunately, I did not see him check the pinion depth on the second install.

I also wish that Dave would have undertaken all of the recommended procedures/measurements the first time, so he and I would not have this extra work/expense, or be looking at his workmanship as the cause of the extra vibration.

I didn't check the pattern because from your driving the vehicle it naturally put a pattern in the gear for me. It was those shiny marks on the pinion and ring gears. I looked at it and it looked good. I didn't check the pinion depth because we didn't change anything from the last time, I reused the same shim on the pinion. I know pinion depth is good because of the gear pattern.

 

[91Notch]

Dave, I found a possible reason for the loss of preload. See underlined:

This is why it took you so much torquing on the pinion nut to get to the desired preload of 20in/lbs (I read it should be 25 actually). Instead of over torquing the pinion nut to reach the desired preload, you should have removed a shim(s) to reach the desired preload.

Please let me know your thoughts on this. Thanks.

Ford spec for the pinion bearing preload is between 16 - 29 inch pounds so according to Fords manual I am within there acceptable range with 20 in lbs. And thats how I have always set them with no problems. I have now called 2 other customers of mine with s197's and asked if they where experiencing any type of vibration and they are all telling me no. If you want bring me the car and leave it with me for a couple days. Bring the stock drive shaft just in case and I will spend the whole month on this if I have to. I have never had a gear make a vibration on me.

 

[MrClean]

Ford spec for the pinion bearing preload is between 16 - 29 inch pounds so according to Fords manual I am within there acceptable range with 20 in lbs. And thats how I have always set them with no problems. I have now called 2 other customers of mine with s197's and asked if they where experiencing any type of vibration and they are all telling me no. If you want bring me the car and leave it with me for a couple days. Bring the stock drive shaft just in case and I will spend the whole month on this if I have to. I have never had a gear make a vibration on me.

With that kind of customer support, man I wish I were in St Pete!

 

[91Notch]

With that kind of customer support, man I wish I were in St Pete!

Thank you. I am this way for many reasons. I use to turn wrench's at a dealership and attended many management meetings. They say for every 1 unhappy customer he will go tell on average of 10 of his friends. Of those 10 on average 5 of them will tell there friends. So by the numbers that's a total of approx 15 customers I may lose. I am not only here to make money I am here to make my customers happy.

 

[Johnmichael]

Thanks for returning, Dave. I'm gonna toss around some questions to see if we can eliminate, or discover some things before I think about bringing it back to you. BTW, I greatly appreciate your willingness to take another look at the car. No matter what happens, I know you tried your best to make it right if it's an install issue, and that's all I could ask.

Wouldn't the gear walk after the first install effect the pattern? According to some of the quotes I posted here, the pinion depth should be rechecked whenever the carrier is removed.

What about the quote about the special depth tool needed for checking Ford OEM gears? You mentioned not knowing what brand gear I brought you, so it's safe to say you didn't use that tool, correct?

What about the quote about removing shims if the preload is too loose? Wouldn't this procedure work better instead of torquing the pinion nut till it reached the proper preload? When you torque a pinion nut too much couldn't it crush the crush sleeve too far, and wouldn't that cause a problem? I ask this because we didn't check the torque on the pinion nut after setting the preload to 20 in/lbs. As for the preload range, I read it should be 15 w/ old bearings, 25 w/new bearing. Whether that's true, I don't know.

The stock DS is trashed, so bringing it is out of the question. I cannot see how the Spyder DS would come into play since the bad vibration started before I put it on. The fact that it got rid of some of the vibration when I put it on, and that it all went away at the beginning of the trip back home after the second gear install would lead me to think it's not a DS related issue.

I'm going to check some other possible vibration causes things this coming week such as wheel balance and suspension bushings. Hopefully I'll find something there that may be contributing to the vibration.

 

[91Notch]

Thanks for returning, Dave. I'm gonna toss around some questions to see if we can eliminate, or discover some things before I think about bringing it back to you. BTW, I greatly appreciate your willingness to take another look at the car. No matter what happens, I know you tried your best to make it right if it's an install issue, and that's all I could ask.

Wouldn't the gear walk after the first install effect the pattern? According to some of the quotes I posted here, the pinion depth should be rechecked whenever the carrier is removed.

What about the quote about the special depth tool needed for checking Ford OEM gears? You mentioned not knowing what brand gear I brought you, so it's safe to say you didn't use that tool, correct?

What about the quote about removing shims if the preload is too loose? Wouldn't this procedure work better instead of torquing the pinion nut till it reached the proper preload? When you torque a pinion nut too much couldn't it crush the crush sleeve too far, and wouldn't that cause a problem? I ask this because we didn't check the torque on the pinion nut after setting the preload to 20 in/lbs. As for the preload range, I read it should be 15 w/ old bearings, 25 w/new bearing. Whether that's true, I don't know.

The stock DS is trashed, so bringing it is out of the question. I cannot see how the Spyder DS would come into play since the bad vibration started before I put it on. The fact that it got rid of some of the vibration when I put it on, and that it all went away at the beginning of the trip back home after the second gear install would lead me to think it's not a DS related issue.

I'm going to check some other possible vibration causes things this coming week such as wheel balance and suspension bushings. Hopefully I'll find something there that may be contributing to the vibration.

Pinion depth is determind by the housing, not the gear it self. I always take the old shim off the old gear and install it on the new one. It always works out the same. So the tool is a universal tool for all 8.8 Fords. Unless your gear was machined totally wrong it works out to use the same shim as the old one. Plus pinion depth will cause a horrible whine, not a vibration. Here's how to do it:

1. NOTE: Apply only a light oil film on the drive pinion bearings before assembling the tools. Assemble and position the special tools.

1. NOTE: This step duplicates final drive pinion bearing preload. Tighten the special tool.

• • Tighten to 2.2 Nm (60 inch lbs.) .

1. NOTE: The special tool must be offset to obtain an accurate reading. Rotate the special tool several half-turns to make sure of correct seating of the drive pinion bearings and position the special tool.

1. Install the special tool.

1. Position the special tool.
2. Install the differential bearing caps.
3. Install the 4 differential bearing cap bolts.

• • Tighten to 105 Nm (77 ft. lbs.) .

1. NOTE: Drive pinion bearing adjustment shims must be flat and clean. NOTE: A slight drag should be felt for correct drive pinion bearing adjustment shim selection. Do not attempt to force the drive pinion bearing adjustment shim between the gauge block and the gauge tube. This will minimize selection of a drive pinion bearing adjustment shim thicker than required, which results in a deep tooth contact in final assembly of integral axle assemblies. Use a drive pinion bearing adjustment shim as a gauge for drive pinion bearing adjustment shim selection.

• • After the correct drive pinion bearing adjustment shim thickness has been determined, remove all of the special tools.

Yes the gear pattern changed when you lost the preload (made it go deeper) but I could see where the pinion depth originally started and by looking at that starting point is where I made the decision that it was ok.+

Here are the Ford specs right out of the manual. I don't know where your getting your specs from but here are the specs I go by:

Notes

Notes

And for how I set the preload that is how I always do it and never have problems.

 

[MrClean]

Man, this a wealth of info....KIMMER/HAWG/94TBIRD/DON_W can we merge/append this thread to the Spyder DS install sticky?