Torque arm mount issue - help
08-20-2012, 10:08 PM
#1
10 Second Club
Thread Starter
iTrader: (5)
Join Date: Aug 2012
Location: NW Indiana
Posts: 718
Likes: 0
Received 0 Likes
on
0 Posts
Torque arm mount issue - help My new weekend toy, a 2000 Formula has a clunk that I can feel in my feet through the floor when driving slow. I jacked it up tonight to inspect and couldn't find anything wrong at first...it has all G2 rear suspension including a G2 torque arm. I saw a shiny scrape on the front of the driveshaft upon a closer look. The torque arm mounts to a small crossmember far behind the transmission and appears to be flexing the floor to the point that the driveshaft is hitting the driveshaft loop. Whoever built this car welded in rectangular tubing as subframe connectors. My assumption is that the torque arm mount should also bolt to a triangulated subframe connector to reinforce the sheet metal mounts.
I haven't been able to find any G2 triangulated subframe connectors online so I was wondering if anyone has any experience with a similar issue or any good ideas for a fix. I am wondering if I can weld in reinforcements somehow but wouldn't know how I could triangulate it properly.
Any ideas or recommendations?
I haven't been able to find any G2 triangulated subframe connectors online so I was wondering if anyone has any experience with a similar issue or any good ideas for a fix. I am wondering if I can weld in reinforcements somehow but wouldn't know how I could triangulate it properly.
Any ideas or recommendations?
08-20-2012, 10:40 PM
#4
10 Second Club
Thread Starter
iTrader: (5)
Join Date: Aug 2012
Location: NW Indiana
Posts: 718
Likes: 0
Received 0 Likes
on
0 Posts
Its an Energy Suspension mount and solid as a rock...I am pretty confident it's floor flex - the sheet metal mounts even appear to show beginning stages of cracks - you can't see it in the pics but that metal is definitely stressed. I really think it's happening more on deceleration and slow moving across a parking lot. It never makes a noise on acceleration.
08-21-2012, 06:21 PM
#6
Your G2 appears to be identical to a Sphon tunnel mount torque arm. I have a Sphon (same model) in my car. It appears to be the same as yours. See link below.
The torque arm is supposed to swivel on the tunnel mount. The fact that it swivels (move back and forth) relieves stress on the tunnel mount itself where it mounts to the brackets on the bottomside of the floor.
Follow Spohn's instructiona when tightening the two self locking nuts on the bolts that hold the torque arm on the tunnel mount bracket. The are NOT to be tightened so much that they restrict movement.
The rear of the torque arm that mounts to the rear end has two bolts to hold it in place. The two bolts must be loosened in order to set pinion angle. After pinion angle is set they should be tightened so much that they won't allow the rear of the torque arm move in the bracket that attaches to the rear end. Doing so maintains a static pinion angle.
It's possible that whoever set pinion angle didn't loosen these two bolts and instead just adjusted the adjustment nut when setting the pinion angle which for sure would put additional stress on the front mount.
It looks as if two of the bolts that hold the front tunnel mount to the floor are longer than required and as a result washers added have been added in order to stop the longer bolts from being screwed into the floor. Get the correct length bolts and get rid of the extra washers.
There should be a thin piece of rubber between the tunnel mount brackets and the floor. Any thin piece of rubber (even floor mats) will aid in reducing noise that can resonate up through the shift console.
I would remove the torque arm and examine the swivel points on the front where they attach to the tunnel mount bracket. You are going to have to anyway because the driveshaft will have to be replaced IMO because of the circular cuts in the shaft. It's a failure waiting to happen.
I suspect you will be able to get parts from Spohn if the poly joints are worn out on the torque arm.
I removed the poly joints and replaced with Sphon's delrin spherical rod ends. They are quieter and articulate causing less bind when the torque arms move for and aft and twists when the rearend move up and down on either side.
You will probably always here the clunk as the torque arm loads and unloads when accelerating or when braking at stoplights with this torque arm design.
You will probably have to weld the stress cracks in the floor of the car. The cracks are probably moving just enough to allow the driveshaft to hit and touch the top of the driveshaft loop.
How are your motor mounts? Are they in good condition or worn out.
BTW - you don't have to have a loop unless you drag race the car. It's a safety precaution for the street. Or you can cut the loop off and get a separate bracket for a loop if the loop doesn't provide enough clearance.
When you have the TA off you might want to fabricate a flat piece of metal to the two tubes on the tunnel mount. Looks as if they are nearly worn through. Mine is starting to get the same way. I had to raise my car in the front in order to maintain enough clearnace for this type of tunnel mount. As a result my Sam Strano lowering springs stay in the box they came in.
Note: I have a PST 3.5 inch alum driveshaft and although there is less clearance in the driveshaft loop than for a stock 3 inch, there is still enough clearance to allow for the driveshaft to raise and lower in the loop as the car loads and unloads as it accellerates.
See pic in my link below.
http://www.flickr.com/photos/1835930...7623345499537/
http://www.flickr.com/photos/1835930...7623345499537/
hth
The torque arm is supposed to swivel on the tunnel mount. The fact that it swivels (move back and forth) relieves stress on the tunnel mount itself where it mounts to the brackets on the bottomside of the floor.
Follow Spohn's instructiona when tightening the two self locking nuts on the bolts that hold the torque arm on the tunnel mount bracket. The are NOT to be tightened so much that they restrict movement.
The rear of the torque arm that mounts to the rear end has two bolts to hold it in place. The two bolts must be loosened in order to set pinion angle. After pinion angle is set they should be tightened so much that they won't allow the rear of the torque arm move in the bracket that attaches to the rear end. Doing so maintains a static pinion angle.
It's possible that whoever set pinion angle didn't loosen these two bolts and instead just adjusted the adjustment nut when setting the pinion angle which for sure would put additional stress on the front mount.
It looks as if two of the bolts that hold the front tunnel mount to the floor are longer than required and as a result washers added have been added in order to stop the longer bolts from being screwed into the floor. Get the correct length bolts and get rid of the extra washers.
There should be a thin piece of rubber between the tunnel mount brackets and the floor. Any thin piece of rubber (even floor mats) will aid in reducing noise that can resonate up through the shift console.
I would remove the torque arm and examine the swivel points on the front where they attach to the tunnel mount bracket. You are going to have to anyway because the driveshaft will have to be replaced IMO because of the circular cuts in the shaft. It's a failure waiting to happen.
I suspect you will be able to get parts from Spohn if the poly joints are worn out on the torque arm.
I removed the poly joints and replaced with Sphon's delrin spherical rod ends. They are quieter and articulate causing less bind when the torque arms move for and aft and twists when the rearend move up and down on either side.
You will probably always here the clunk as the torque arm loads and unloads when accelerating or when braking at stoplights with this torque arm design.
You will probably have to weld the stress cracks in the floor of the car. The cracks are probably moving just enough to allow the driveshaft to hit and touch the top of the driveshaft loop.
How are your motor mounts? Are they in good condition or worn out.
BTW - you don't have to have a loop unless you drag race the car. It's a safety precaution for the street. Or you can cut the loop off and get a separate bracket for a loop if the loop doesn't provide enough clearance.
When you have the TA off you might want to fabricate a flat piece of metal to the two tubes on the tunnel mount. Looks as if they are nearly worn through. Mine is starting to get the same way. I had to raise my car in the front in order to maintain enough clearnace for this type of tunnel mount. As a result my Sam Strano lowering springs stay in the box they came in.
Note: I have a PST 3.5 inch alum driveshaft and although there is less clearance in the driveshaft loop than for a stock 3 inch, there is still enough clearance to allow for the driveshaft to raise and lower in the loop as the car loads and unloads as it accellerates.
See pic in my link below.
http://www.flickr.com/photos/1835930...7623345499537/
http://www.flickr.com/photos/1835930...7623345499537/
hth
Trending Topics
08-21-2012, 07:41 PM
#8
10 Second Club
Thread Starter
iTrader: (5)
Join Date: Aug 2012
Location: NW Indiana
Posts: 718
Likes: 0
Received 0 Likes
on
0 Posts
Thanks a million dlandsvz28!!! I am an old muscle car guy and due to circumstances out of my control have found myself in the LS body world - I am really glad it happened! lol These LS fbodies are awesome cars - my son has a 98 z28 and I have an 00 ram air formula.
I see that you do not have the triangulated subframe connectors so must not think they are necessary? I was thinking that they may be part of the solution to the stressed floor issue.
Once again thanks for the explanation. I will get to work. Your z28 is a fabulous car by the way...AND CLEAN!!!
I see that you do not have the triangulated subframe connectors so must not think they are necessary? I was thinking that they may be part of the solution to the stressed floor issue.
Once again thanks for the explanation. I will get to work. Your z28 is a fabulous car by the way...AND CLEAN!!!
08-21-2012, 09:16 PM
#9
You are welcome and hope that my explanation helped a bit.
You can download all of the Sphon instructions from their site which probably explain how the TA works better than mine.
I do have subframe connectors. They are BMR and run the down the inside of each frame rail from the front jack point to just ahead of the rear lower control arms.
They for sure stiffen the chassis. When I jack the car on one side the other side will lift off the ground also. As a result I have to be very careful when setting jackstands under the car. They can get loose if the car is not jacked evenly on both sides front or rear.
Just a heads up - be safe.
I am an oldie too - 65 but closer to 66.
You can download all of the Sphon instructions from their site which probably explain how the TA works better than mine.
I do have subframe connectors. They are BMR and run the down the inside of each frame rail from the front jack point to just ahead of the rear lower control arms.
They for sure stiffen the chassis. When I jack the car on one side the other side will lift off the ground also. As a result I have to be very careful when setting jackstands under the car. They can get loose if the car is not jacked evenly on both sides front or rear.
Just a heads up - be safe.
I am an oldie too - 65 but closer to 66.
Last edited by dlandsvZ28; 08-22-2012 at 06:31 PM.
08-22-2012, 02:14 PM
#10
10 Second Club
Thread Starter
iTrader: (5)
Join Date: Aug 2012
Location: NW Indiana
Posts: 718
Likes: 0
Received 0 Likes
on
0 Posts
My old is 43 - but closer to 44. LOL I am very educated and experienced with old chevy muscle cars but these 4th gens are new to me and my son. Lovin' them though.
I have subframe connectors also and my car does the same thing when jacking up. Scared me silly the first time it almost slipped of stands. I was thinking maybe the triangulated connectors were a requirement when using this type of torque arm but I guess not since yours is working fine. I will remove the arm and crossmember thursday evening to clean/inspect everything and fire up the welder. I am hoping I can repair the floor without removing seats and carpet but I have a feeling I may have to structurally support that tunnel mount area somehow. This is going to turn into a larger project then I had anticipated - When I acquired this car I thought for sure the thumping was noise was just the rubber front torque arm mount. argh...not that simple. I will keep you posted with my progress.
I also have a leaking pinion seal on that moser 12 bolt so I am going to replace the crush sleeve, fluid and seal while I am under there. Gears appear to be shiny on the edges of teeth - I thought they'd be shiny in the middle. Is this normal?
I have subframe connectors also and my car does the same thing when jacking up. Scared me silly the first time it almost slipped of stands. I was thinking maybe the triangulated connectors were a requirement when using this type of torque arm but I guess not since yours is working fine. I will remove the arm and crossmember thursday evening to clean/inspect everything and fire up the welder. I am hoping I can repair the floor without removing seats and carpet but I have a feeling I may have to structurally support that tunnel mount area somehow. This is going to turn into a larger project then I had anticipated - When I acquired this car I thought for sure the thumping was noise was just the rubber front torque arm mount. argh...not that simple. I will keep you posted with my progress.
I also have a leaking pinion seal on that moser 12 bolt so I am going to replace the crush sleeve, fluid and seal while I am under there. Gears appear to be shiny on the edges of teeth - I thought they'd be shiny in the middle. Is this normal?
08-22-2012, 08:47 PM
#11
This is what the tunnel mounts look like sans undercoating.
http://www.flickr.com/photos/1835930...7623345499537/
When I first mounted the tunnel mount bracket I thought too that the bolts holding the ta tunnel mount bracket to the floor were 'kinda' small for their purpose. But my bracket has been on since 2004, so one would think that if there were going to be any stress cracks, they would be visible by now.
There is however, a tiny stress crack on the tailshaft of my A4 tranny which is why ta tunnel mount brackets were created in the first place - to keep the tailshaft from breaking because of the stock ta mounting on the tailshaft of the transmission.
But my car has never been exposed to a trans brake or seen track duty where the stress put on the frame and ta mount is much much greater than what my car has been exposed too.
Even so, if this location for the ta tunnel mount bracket wasn't considered adequate for most applications, I think by now - with at least 8 or 9 years of history - there would be a number of posts about stress fractures. Nor would the sponsors here continue to sell or promote the tunnel mount as the preferred mounting location over the transmission mount location.
This is just speculation, but I suspect that perhaps the bracket wasn't installed correctly, the attaching bolts worked loose, and the loose or missing bolts caused the stress cracks.
The ta tunnel mount bracket attaching bolts by design are a specific length. Too short and they will barely thread into the welded nuts on the floor brackets, or too long and they will screw into the floor of the car. Since washers have been added to account for extra length on two of the bolts we know the original bolts are long gone. Hopefully the attaching nuts aren't crossthreaded as well.
Sorry about all of the undercoating. You got a big job ahead of you before you can start welding.
Be aware that when you remount your ta bracket to the rear end housing (assuming you have a 12 bolt) that the bolts are too short and can work loose. And the top two are very difficult to get tight. I recall I had to lower the rearend to get enough room to get a decent sized torque bar to lock them down. Some wire tie the bolt heads to keep the bolts from backing out.
As for your Moser. I know very little about gear setup but there are two or three pros on the 'gears and axles' forum who appear to know what they are talking.
I sold my Moser 12 bolt and reinstalled my 10 bolt. I got tired of the whine plus I wanted to lower the car.
https://ls1tech.com/forums/gears-axl...installed.html
http://www.flickr.com/photos/1835930...7623345499537/
When I first mounted the tunnel mount bracket I thought too that the bolts holding the ta tunnel mount bracket to the floor were 'kinda' small for their purpose. But my bracket has been on since 2004, so one would think that if there were going to be any stress cracks, they would be visible by now.
There is however, a tiny stress crack on the tailshaft of my A4 tranny which is why ta tunnel mount brackets were created in the first place - to keep the tailshaft from breaking because of the stock ta mounting on the tailshaft of the transmission.
But my car has never been exposed to a trans brake or seen track duty where the stress put on the frame and ta mount is much much greater than what my car has been exposed too.
Even so, if this location for the ta tunnel mount bracket wasn't considered adequate for most applications, I think by now - with at least 8 or 9 years of history - there would be a number of posts about stress fractures. Nor would the sponsors here continue to sell or promote the tunnel mount as the preferred mounting location over the transmission mount location.
This is just speculation, but I suspect that perhaps the bracket wasn't installed correctly, the attaching bolts worked loose, and the loose or missing bolts caused the stress cracks.
The ta tunnel mount bracket attaching bolts by design are a specific length. Too short and they will barely thread into the welded nuts on the floor brackets, or too long and they will screw into the floor of the car. Since washers have been added to account for extra length on two of the bolts we know the original bolts are long gone. Hopefully the attaching nuts aren't crossthreaded as well.
Sorry about all of the undercoating. You got a big job ahead of you before you can start welding.
Be aware that when you remount your ta bracket to the rear end housing (assuming you have a 12 bolt) that the bolts are too short and can work loose. And the top two are very difficult to get tight. I recall I had to lower the rearend to get enough room to get a decent sized torque bar to lock them down. Some wire tie the bolt heads to keep the bolts from backing out.
As for your Moser. I know very little about gear setup but there are two or three pros on the 'gears and axles' forum who appear to know what they are talking.
I sold my Moser 12 bolt and reinstalled my 10 bolt. I got tired of the whine plus I wanted to lower the car.
https://ls1tech.com/forums/gears-axl...installed.html
Last edited by dlandsvZ28; 08-22-2012 at 08:53 PM.
08-24-2012, 11:10 PM
#12
10 Second Club
Thread Starter
iTrader: (5)
Join Date: Aug 2012
Location: NW Indiana
Posts: 718
Likes: 0
Received 0 Likes
on
0 Posts
Well, dug into the undercoating. Someone already repaired the floor and that is why the undercoating was there. It really doesn't look terrible so I reworked the drivers side since they had it off a little. I also removed the driveshaft loop. The driveshaft was hitting the loop on deceleration but is not damaged - those marks aren't bad - appear to be just through surface paint. I will most likely replace my subframe connectors with the triangulated style this winter and install these straight ones on my sons camaro just to firm up the mounting points. That will ease my mind about the mounting points being repaired at one time.
I replaced the crush sleeve and pinion seal in the rear end. The gear whine is MUCH better now and the seal is dry after an 80 mile cruise. This 12 bolt still whines a little at highway speed and is quiet on deceleration but I hear that is quite common with these high performance gear sets.
I replaced the crush sleeve and pinion seal in the rear end. The gear whine is MUCH better now and the seal is dry after an 80 mile cruise. This 12 bolt still whines a little at highway speed and is quiet on deceleration but I hear that is quite common with these high performance gear sets.
08-25-2012, 09:33 AM
#13
I'll bet the whine although generated from the rearend, is amplified because of the style torque arm you have.
I too have been complaining about whine from both my Moser and stock rear end. I was able to find a post I made way back in 2004 just after installing the Spohn PN 405 torque arm. No whine with the stock transmission ta, but as soon as I installed the Spohn PN 405, I could hear whine.
Both UMI and BMR admit that we will get whine with a tunnel mount ta.
I have found that I can reduce whine the closer I get to setting pinion angle to almost zero.
There are self locking nuts on the swivel joints (rotator) on the tunnel mount. If the self locking nuts are too loose - you get the thump sound on accel or decel. Set them too tight and you get more whine. The top nut is torqued to 100 lbs and the bottom front nut is torqued to 50 lbs per Spohn instructions.
A poly mount - tunnel mount ta transmits less noise than the swivel (rotator) mount on the Spohn 405.
http://www.spohn.net/shop/1998-2002-...ersY-Pipe.html
hth
I too have been complaining about whine from both my Moser and stock rear end. I was able to find a post I made way back in 2004 just after installing the Spohn PN 405 torque arm. No whine with the stock transmission ta, but as soon as I installed the Spohn PN 405, I could hear whine.
Both UMI and BMR admit that we will get whine with a tunnel mount ta.
I have found that I can reduce whine the closer I get to setting pinion angle to almost zero.
There are self locking nuts on the swivel joints (rotator) on the tunnel mount. If the self locking nuts are too loose - you get the thump sound on accel or decel. Set them too tight and you get more whine. The top nut is torqued to 100 lbs and the bottom front nut is torqued to 50 lbs per Spohn instructions.
A poly mount - tunnel mount ta transmits less noise than the swivel (rotator) mount on the Spohn 405.
http://www.spohn.net/shop/1998-2002-...ersY-Pipe.html
hth
