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Discussion Starter · #1 ·
My '02 V6 5sp 'bird is my daily driver. I live in a section of Philly full of potholes so I needed to address the transmission mount setup after it broke a few times. Everyone knows the stock mount rips easily. The last straw was actually when my torque arm bracket broke loose from the tailshaft on vacation. The bolt popped out, taking threads with it, and a machine shop tapped it out bigger by lowering the trans a little to get access. I drove for several months until Eric at BMR helped me come up with this solution. That repair held.

The goal is to get the TQA (torque arm) off the tailshaft. Other companies make relocation brackets but nobody makes one for a V6. Eric was willing to put the time in on the phone and through numerous emails. What worked was using BMR's "rear perched" TCC010 (with the straight bar) and extending the mount position forward with a 6" tongue of 3/16 steel, switching to a shorter transmission mount - EnSusp 3.1158 - and isolating everything with G1356354 from Zoro.com. It's orange, 1/8" silicone rubber that withstands -60 to 400 Fahrenheit, with a durometer of 60A and tensile strength of 500PSi. You can chuck your factory crossmember and puck shaped mount if this solution works for you. It takes some minor modification and I'm the only one I know to test this so far, so try it at your own risk and be smart about it.

Here's the details:
1. Chevy confirms that the V6s use the same trans crossmember for both auto and manual trans, in 4th gen F-bodies.

2. You can use an Energy Suspension 3.1142 universal trans mount to replace the stock mount and keep your crossmember, but it's hard as a rock and transfers engine noise to the frame.

3. You can quiet that noise by putting a layer of silicone rubber between the xmember and the frame, the xmember and the mount, and the mount and the trans. If you use the shorter EnSusp 3.1158 you've got more room for rubber. (Get out your tape measure!) If you don't want to get your TQA off the tailshaft, you can stop here. Easy solution to ripping stock trans mounts. While you have your stock xmember out, widen the center hole a little.

4. V6s have better ground clearence due to slimmer/single exhaust. The TCC006 Torque Arm Crossmember (TQA Reloc Xmember) for the T56 trans hangs too low for parking garage ramps. It dips down in a "U" shape, whereas the bar on the TCC010 goes straight across. Your V6's smaller transmission will fit above the TCC010.

5. The perch for the trans mount on the TCC010 TQA Reloc Xmember is on the rear. You wish it was on the front. Make friends with someone in a metal shop. You need a 2.5" x 6" tongue of 3/16" steel with holes drilled 3/4" from each end. Slot them out a little to give yourself wiggle room.

6. If you want to be able to go over a speed bump, cut the bottom corner off the fin that the TQA mounts to. The middle holes are stock height; upper holes bring the rear wheels in and reduce traction (good for drifting); lower holes push the wheels out and increase traction (good for snow). You don't need those lower holes to get to work or the grocery store; and if you drive this thing in the snow, get snow tires. Draw a line from the bottom of the fin at the bar - WITHOUT DISTURBING THE WELD - to the top of the hole BELOW the lowest hole you need for mounting the TQA retainer bracket. Cut that corner off.

7. You'll notice the perch sticks up over the bar of the xmember, leaving just enough room to slip the steel tongue under it. Fasten it on with the biggest grade 8 hardened bolt you can fit. Nut faces down so if it spins off you'll still have the bolt. Carry a spare. Put it on tight. Use a lock washer or second nut to lock it on tight. I've never had a problem and it's been on for a year.

8. It's important to slip a rubber shim UNDER that steel tongue; find a scrap of something thin, the Zoro stuff won't fit. Double it up on one side, the bar has a slight curve. This cuts down on the "diving board" feel.

9. Put Zoro rubber between the following metal to metal contact areas: xmember to car body, tongue to trans mount, trans mount to trans. The Energy Suspension engineer told me NOT to throw out the metal "spacer" as it is a PRE-LOAD PLATE for between the mount and the trans. I thanked him for the info and replaced it with an extra layer of rubber anyway. The 3.1158 is only 1-5/8" tall, allowing room for three strips of rubber between it and the transmission. It makes the trans mount feel more like stock, but you might not want that on the track. I also like to put rubber under washers under the bolt heads, but you have to be more careful doing that.

10. CHECK TORQUE BY FEEL, NOT BY SPEC, and CHECK IT AGAIN NEXT WEEK and NEXT MONTH! The rubber will throw off your readings, so you gotta guess. DO NOT PUT RUBBER BETWEEN PERCH AND TONGUE it won't help and might rip apart easily. Be sure to measure layers and watch what you are doing to the pinion angle. Ideally your tailshaft should sit about 1/8" lower than it used to, improving propeller shaft angles and efficiency.

11. You will now have to fix your sagging shifter boot and make it perfect, or it will get in the way of 2nd gear. You can get a metal boot retainer clip from some guy on eBay and use a hose clamp to fasten the boot top to the shift knob, which solves that problem cheaply.

12. When you take off the original TQA mount hardware from the tailshaft, you'll lose a through-bolt. I made one out of threaded rod because it was available, but a real bolt is a better option. Have a few sizes and a pile of washers and nuts handy. You'll also have to adjust the position of the vibration damper while you're at it; you can move it with a pry bar.

13. Have spare bolts, nuts, washers, and Zoro rubber. Make two tongues. Drive carefully and check torque till you're certain everything is safe and solid. Keep your stock equipment. Don't blame me if you screw it up! I can think of several improvements on this idea, but what I've described has worked for over a year on my car with no issues.

14. If your trans came out while you were at it, put Zoro rubber between the shifter housing and the body. There's a guy on eBay who cuts them for you if you want, I think his site is Stang Shifter or something.
 

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1994 Firebird Formula 381ci LT1 / TH400+GV O/D
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Interesting. Roads must be pretty bad.

What do you mean in Item #6 about pushing the wheels "out" or "in"? I understand the concept of "instant center". It's important in determining how the tires get loaded on a very hard launch. But raising or lowering the front of the torque arm also changes the pinion angle on a non-adjustable torque arm. What part of the wheel moves "in" and "out" when this happens? Have you verified that with the changes to the trans support height, and the choice of mounting holes for the front bushing, that the pinion angle is still within spec?
 

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Great writeup, just a little hard to follow without being under the car to identify what your talking about. lol
 

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Discussion Starter · #4 ·
Interesting. Roads must be pretty bad.

What do you mean in Item #6 about pushing the wheels "out" or "in"? I understand the concept of "instant center". It's important in determining how the tires get loaded on a very hard launch. But raising or lowering the front of the torque arm also changes the pinion angle on a non-adjustable torque arm. What part of the wheel moves "in" and "out" when this happens? Have you verified that with the changes to the trans support height, and the choice of mounting holes for the front bushing, that the pinion angle is still within spec?
I mean the wheels kinda go out towards the rear bumper or in towards the center of the vehicle. I can't tell you what setting is right for your driving style but I can say that BMR thought about the pinion angle when they designed the adjustment range. Personally I wouldn't stray far from the middle holes without good reason and without observing the change in pinion angle; but then again I'm after a close to stock feel.

Yeah the roads are pretty bad here!
 

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1994 Firebird Formula 381ci LT1 / TH400+GV O/D
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The wheels on a solid rear axle can't really move in (toe in) or out (toe out). So I still don't know what you mean. Or are you saying the wheels (with the entire rear axle) move forward or backwards as the arc of the rear lower control arms changes the distance between the chassis mount for the LCA and the centerline of the axle?
 
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