Installing the Steve Spohn Adjustable Torque Arm
Updated: February, 2002
I've installed the Steve Spohn suspension onto the Trans
Am back in 2000. It really made a huge difference in terms of traction! If you
have ever listened to my sound byte called "zero to
65", you will hear a VERY slow shift to second gear. Now, this isnt a
slow shift: It's wheelspin. After I finished the modifications to the L69 305,
(affectionately nicknamed the "feeble305"), I found that the 5800 RPM
shift to second gear would spin the tires so badly that the speedometer would
bury itself, then stabilize at 60 MPH and begin climbing from there. I found
that the installation of the torque arm BY ITSELF is not the straight path to
traction. You must also include upgraded lower control arms and a panhard rod.
These two parts installations are not covered in this install page. I only cover
the torque arm here.
Now, Are you considering the installation of one of these torque
arms yourself? If so, here's some pictures and tips on how to do it. The
total installation time took about 3.5 hours due to a couple of unforseen
problems. If you read to the end, then you ought to be able miss these
problems for an easy, trouble-free installation. Don't forget: If you are
considering the order of one of these pieces, dont buy it first. Buy Steve's
lower control arms, his panhard rod, weld-in mounting brackets, and THEN the
torque arm. If I would to do it a second time, I would order it all at once.
Also note: The torque arm shown
here is an early design, built when it was just Steve and his dad in the shop.
He has been very responsive to customer feedback (such as this page), and has
greatly improved the fitment and design of the torque arm. Long-tube Hooker
header owners beware: This design is not (at present) compatable with long-tubes
that are installed to Y-pipes and Mufflex systems. At least, I dont think it is!
Call Steve Spohn for the latest details.
|Steve's adjustable torque arm relocates
the torque arm mount off the transmission tailshaft and onto the transmission
crossmember. This reduces forces from the axle onto the transmission tailshaft.
I have dents in my transmission tunnel where the tailshaft smacked into
the tunnel when the OEM mount broke.
1) Notice the ramps. I jacked the car up,
put it on jackstands, then jacked it up some more. I then slid the ramps
under the front tires, and jacked up the rear. I measured the fenderwell
height to the floor and matched it in the rear. I think the fenderwell
is 36-inches up. Normal ride height is 27 inches. Be careful with ramps:
When you jack up the rear-end, be sure the car doesn't slide down the ramps
and through the garage door! In retrospect, I should have turned them around.
2) The yellow jackstands support the transmission.
This lets me remove the crossmember. There is a 2 x 4 between the jackstands
and it supports the oil pan.
|Steve's design is nice; although my safety
loop had this hex bolt that is used as a rivet: It was tall enough that
it hit the bracket when the rod-end is positioned straight-up. I got me
a nice sharp bastard file and filed it down to fit. I also could hear the
"clack! clack!" of the safety loop on the bracket, and I worried that it
would be noisy under the car. Thus, I got me some 1/16" mylar-backed closed-cell
neoprene with adhesive and stuck it to the inside of the bracket. Steve
has since revised his design and opened up this bracket to remove any interference.
|One difficulty I ran into was the old
torque arm bolts: they couldn't slide out the top withut running into the
floorpann of the car. A jack with a 4X4 block was perfect: I raised the
chassis temporarily in order to slide the bolts out. I left the body raised
until I had the new torque arm in place. Once I slid the bolts through
the holes, I removed the jack to restore proper height. One note: I have
four jackstands, and a hydraulic scissor jack. I used them all on this
project. I also have an Ingersoll-Rand impact gun: It made removal of the
torque arm bolts a piece of cake.
I ran into problems with the safety loop crunching
into the speedometer cable. I was scratching my head as to what to do at
this point. I even considered slotting the crossmember holes, as well as
the transmission mount. In the end, inspiration struck while drinking a
cup of stale coffee the next afternoon at work: Back out the rod end! There's
no reason why you can't simply back out the rod end until it just touches
the safety loop. This effectively relocates the safety loop rearwards in
relation to the crossmember mounting points. It worked. I now have .125"
clearance. It's still tight, but plenty of clearance.
Steve has since changed his crossmember
design to alleviate this potential problem.
|You'll want to remove that old torque
arm bracket. I found that the easiest thing to do was take the top mounting
bolt and reattach the nut & screw it down, rather than try to tip the
whole transmission out of the tunnel. In addition, one of the bolts is
riveted to the torque arm bracket. I couldn't get it out without tipping
the transmission a lot, so I got out my cutoff wheel and chopped the bolt
in half. I replace the bolt with a 4-inch 3/8 Stainless bolt, and a lock
nut. The bolts are required to hold the catylitic converter hangar in place.
Mike Metzler has an alternate method that he
claims is even easier:
There is a much easier way to
remove the torque arm mount than what is in your article. The method I use is
to remove the driveshaft (piece of cake), then remove the tailshaft housing (4
bolts, another piece of cake). You will lose a small amount of tranny fluid,
so have a pan ready. Once the tailshaft is off, you can easily get the bolts
out of the mount.
That would also be a good time to elongate the holes in the bracket for the
CAT. By making the holes a little larger there and on the part of the bracket
that bolts to the cat, you can gain up to a 1/4 inch of clearance between the
cat and your subframe connectors.
|Steve Spohn has a nice web site. He's
very accessable and has his own tech forum. If you need suspension upgrades,
|Some other observations: Removal of the
original torque arm can be made easier if you first loosen up the bolts
on the differential. These are, I think, 13/16". You'll need the boxed-end
wrench at the top, and an impact wrench or big breaker bar on bottom.
Next, you'll need a 15MM boxed-end wrench,
a 15MM socket and half-inch drive ratchet. There are two nuts at the top
of the mounting bracket that you must remove in order to open the clam-shell.
Pivot the transmission downwards out of the tunnel a little bit to gain
access to these bolts. Be careful not to go too far and bust off your distributor
or oil sending unit...
Finally, don't forget to buy a new transmission
mount. I replaced mine in 1993 with a new OEM dealership mount, and it
was really cracked up six years later. I bought an Energy suspension polyeurethane
mount from Summit Racing Equipment for $22 or so... I got a nice bright
red one for the heck of it. I was worried about the height of the transmission
tailshaft, and the fact that it was sitting higher than the original installation.
My torque converter rattles on the subframe connector now. I was a little
concerned that perhaps the tailshaft/driveshaft angle was incorrect, with
the new crossmember. Well, I checked it, and found that the angle was half-a-degree
or less. Perfect! I guess my old transmission mount must have sagged
over the years, and the use of the Spohn crossmember and Energy Suspension
poly mount corrected the angle.
I'll leave the alignment tips to Steve
Spohn. He provides several pages of documentation on how to measure the
relative angles between the driveshaft and the pinion. As it turns out,
the angle of the car body with respect to gravity is not as important as
I thought it was. The most important detail is that the rear axle be at
proper ride height. This means that you'll want the weight bias to be as
if the car was parked on pavement. In other words, weight on the front
tires. Don't put the car on jackstands on the front subframe. It will uncompress
the rear springs and mess up your angles.
My adjustable torque arm was pre-adjusted,
I guess. I wanted 1.5 degrees of negative pinion angle, and the torque
arm as delivered hit right between 1.5 and 2 degrees. I played around with
it for laughs, but returned it to the original setting.
|Adjusting the torque arm using the angle finder.
Place the angle finder on the flat portion of the torque arm, and record
the angle. I've since modified my procedure to read the angle directly
from the Universal joint bearing cap face. I glued a flat machinists magnet
to a piece of flat bar stock, upon which the angle finder is mounted. The
3/4" magnet is then fixed to the pinion end of the universal joint, and
the angle recorded. It is a more direct measurement, but yields the same
results. At least to the accuracy of this angle finder, which is +-0.5
|Measurement on the driveshaft.
This measurement is a bit more suspect because we try to attach a flat
magnet to a cylindrical object. Again, by reading directly at the U-joint,
the accuracy is not in question, assuming the bearing cap end is true.
Mine yielded the same results.
If you have
comments or suggestions, just email
|There's more hobbyist stuff available
at Dan's Third-gen hobbyist page.