American Expedition Vehicles Tummy Tucker – TJ Rubicon models - Manual (Page 11)

Installation Instructions: Tummy Tucker™ – TJ Rubicon models
Nth30116 v4.doc page 11 of 13 www.aev-conversions.com
Caution: Debris Accumulation on top of TT. The TT does not have any large clearance or
drainage holes on the bottom surface to eliminate the possibility of snagging a rock, etc. in such
holes. On the other hand, the lack of holes and the reduced clearances around the transmission,
transfer case, and exhaust, makes it easier for rocks, twigs, etc. to accumulate on top of the skid
plate and not fall out on their own. Flammable items such as grass and twigs should be kept out of
contact with the hot exhaust or there will be risk of fire – you should clear the TT after each off-road
outing to avoid danger!
Also, (especially on manual transmissions), rocks or other hard items may get lodged under
the transmission adapter bracket – where they will effectively eliminate the isolation proved by the
dual mounts (you may notice more vibration), and if left uncleared this could cause the mounts to
deteriorate. Every effort has been made to prevent this from happening, but you should check for
rocks and clear them if found.
powertrain and the TT or body floor. Find the contact and correct as necessary with shims, more floor
mods, etc. (see appendix). Contact during certain rough conditions may occur and is generally not
detrimental – you can test for some things by doing hard launches (t-case may touch floor), and
compression braking (t-case may touch TT) – if the contact is detectable, it may be desirable to increase
the appropriate clearance area. You can also test drive over washboard, but the contact will be hard to
hear – if you provided the proper ¼+” clearances, you will rarely hit and not damage anything.
Next, confirm that the t-case shift linkage still functions properly – that you can get into and out of
both 2-High and 4-Low. If not, the linkage may need readjustment. See the appendix section for
solutions to possible issues that have been found in rare cases.
Note: if you have an automatic and hear 3-4 ‘thumps’ during a hard launch, you don’t have enough
clearance at the dimple. Automatic TJ’s require more clearance due to the torque ‘pulses’ created by the
torque converter. If you already have made the dimple as large as possible (tires were off the ground),
you may need to shim the TT skid down at the frame rails using six ½” washers (about 1/8” thick) – this
can be done without removing the skid (do one side at a time) and should eliminate the issue.
TT on ’03 Rubicon automatic with optional auto trans skid