How to Install the Ford Transit 16-Gallon Undercarriage Water Tank (Passenger Side) | Full Install Guide

Last updated: October 1, 2026

Overview

GoCode's TR-UC-16 tank mounts to your Transit's frame rail using drilled-and-rivnutted brackets, adding 16 gallons of undercarriage water storage without giving up interior space. This guide walks through drilling, priming, and bolting the tank onto the passenger side using the factory muffler bolt as your reference point.

Before You Start

  • Vehicle: Ford Transit

  • Kit: GoCode TR-UC-16

  • Mounting location: Undercarriage, passenger side under the slider door

  • Estimated installation time: ~2 hours

Tools & Materials

  • Tape measure, marker

  • Center punch (optional)

  • Drill

  • Stepper bit, or a series of progressively larger bits, up to 17/32"

  • Rivnut tool (pneumatic or manual)

  • Metal primer (to treat the drilled holes and prevent rust)

  • 9/16" & 1/2" socket

  • What's included with tank purchase: three mounting straps, 3/8" bolts, 3/8" rivnuts, and Loctite

Installation Instructions

  1. Identify the frame rail mounting holes. Using a 1/2" socket, remove the bolt fastening the muffler in place — set it aside, you'll reuse it to mount the first bracket. From there, measure 12-3/4" and 22-1/8" toward the rear of the van, and mark the hexagon-shaped holes at each measurement to be drilled out for rivnuts.

  2. Mark matching placement on the side wall. Hold a bracket straddled between the frame rail and the van's side wall, aligned with the muffler bolt and held perpendicular to the rail, then mark the side wall. Using that first side wall mark as your control point, measure and mark 12-3/4" and 22-1/8" again for the remaining brackets.

  3. Drill out every marked hole to 17/32". Use a stepper bit or a series of progressively larger bits. A punch helps keep the bit aligned on the side wall, and checking your hole size against a rivnut as you go is worth doing, especially with a stepper bit.

  4. Clean up. Sweep away any metal shavings from under the van before moving on.

  5. Prime and install the rivnuts. Treat the exposed, drilled metal with primer to prevent rust, then install a rivnut in each hole with your rivnut tool.

  6. Mount the tank. Lift the tank into place and thread the provided 3/8" bolts, plus the reused muffler bolt, through the mounting brackets and into the rivnuts. Don't tighten anything until every bolt has been started, and use Loctite on all of them. Finish with a 1/2" socket on the muffler bolt and a 9/16" socket on the rest, tightening everything down — then you're ready to plumb.

Transit Undercarriage Tank Installation Video (Passenger Side)

Watch the install below, or follow the written steps above.

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