American Expedition Vehicles Tummy Tucker – TJ Rubicon models - Manual (Page 8)

Installation Instructions: Tummy Tucker™ – TJ Rubicon models
Nth30116 v4.doc page 8 of 13 www.aev-conversions.com
Fig. 13
NOTE: Frame-TT hole alignment: Wrangler frame rails are naturally twisted inward at the bottom due
to the weight of the body pushing down at the outboard mounts – this causes the holes for the skid to
shift closer together than they were intended. The TT is designed to original Jeep CAD dimensions –
and so will hold the frame rails in place and keep your body mounts from sagging, but during
installation, it may appear that the skid is slightly too wide – this is normal.
NOTE: We recommend applying anti-seize compound to the conical shoulder of the bolts (not just the
threads) to make them easier to remove later. Without this, the bolts can ‘bite into’ the powdercoat in
the countersunk holes of the TT and become difficult to remove.
To make it easiest to get all six bolts started, do not set any of the bolts into their countersinks until they
are all started – then snug them up with a wrench. After the clearance check below, torque to 50 ft-lbs.
Step 12: Clearance Checks and Adjustments. Now that the TT is bolted up, you can determine if
adjustments are necessary by letting the jack under the t/case output down until the full weight of the
powertrain is resting on the new isolators. The most important clearance is above and below the t-case
front output because this area moves the most under load. By viewing through the t-case drain hole at
the left-rear of the TT, observe the amount of clearance between the lowest point of the t-case and the
TT – you may use pieces of steel, etc. of known thickness to gage the gap. Due to variations between
vehicles, a few installations may need to ‘shim’ the isolators to keep the transfer case from resting or
bouncing on the TT. Several 3/8” hole x 1.5” diameter ‘fender’ washers were supplied for this purpose
and must be used in pairs on top of each isolator. If you need to add shims, you will probably have to
lower the TT skid to do this easily. You will gain a little more clearance than the thickness of washers
you add – each pair of .090” thick washers will generate about +1/8” (.125”) of additional gap.
Proper installation of your TT will have at least ¼” of space under the front output, and about 3/8”
above it to the floor. If the sum of upper and lower clearance is less than 5/8”, you need to either
clearance the floor (adding or increasing the ‘dimple’ size), or space the TT down at the frame using six
½” washers of equal thickness. If there is 5/8” total clearance, but less than ¼” of it is below the t/case,
you need to add shims above the isolators. If there is 5/8” total clearance, but more than ¼” of it is below
the t/case, then you need to remove shims; if no shims where used, then the floor must be dimpled more
(or the TT skid can be shimmed down at the frame, plus additional fender washers at the isolators).
Please refer back to the table and notes provided in step 4.
At this point you should also check for adequate clearances all the way around the transmission,
transfer case, and exhaust/catalytic converter. Generally there should be at least ¼” of space at all close
gaps between the floor or the TT and these components – if not, the appendix may provide
help/solutions.
Step 13: Bolt Locker Pump/Bracket Assembly to TT. ‘Unhook’ the locker pumps from the fuel line
bundle on the driver’s frame rail and lower the bracket into place on the TT. The rear end flange that you
straightened out in step 6a should slide over the two studs on the main cross rib of the TT. Once this is
done, you should be able to align the elongated
front bracket hole with the countersunk hole in the
TT (the hole about 1.5” back from the front of the
TT and just outboard of the front driveshaft cutout.)
Once this hole is aligned, insert the one additional
(5
th
) 5/16” flathead bolt from below the TT and
through the locker pump bracket hole. Secure the
locker pumps with the three nylock 5/16” nuts
supplied. Note: The flanges on the locker pump
bracket that had been used to hang it should now
be situated close to – but not touching – the fuel
lines. If they are touching, you may bend the
flanges slightly for clearance. If there is too much