The Turtle V – Update #4 – Drivetrain, Suspension & Fuel – 2019

June 7, 2019

Traffic was light in Azerbaijan.

Not the least important part of any vehicle, the drivetrain of The Turtle V has been carefully selected and designed to do a job, reliably.

The front differential of the F550 is a heavy duty Dana 60. We added an ARB Air Locker and protected it with the Dynatrac Pro Series off-road differential cover. The function of the ARB is simple. It is air actuated from our 5 gallon AccuAir air tank which is constantly kept full, (120 psi), by our twin ExtremeAire Magnum 12 Volt Compressors by Extreme Outback Products. If we start to lose traction it’s simply a matter of pushing a button on the dash and the ARB locks the front axles together like a spool, giving maximum traction to both wheels at the same time. Otherwise the front differential remains totally open for comfortable normal driving. ARB Air Locker has proven its reliability in both The Turtle III & IV.

The rear axle holds a massive Detroit S135 fitted with a Detroit Truetrac (by Eaton) limited slip. The Truetrac operates as a standard or open differential under normal driving conditions, allowing one wheel to spin faster or slower as necessary. When a wheel encounters a loss of traction or the terrain changes, the gear separation forces take effect and transfer torque to the high-traction wheel. The helical-shaped gears mesh with increasing force until wheel spin is slowed or completely stopped. When the vehicle exits the low traction situation, the differential resumes normal operation. We tried the Detroit Locker but it proved to be much too aggressive on hairpin gravel roads and even on pavement. ARB does not make one for the Detroit S135.

(See Turtle V Blog Part II for information on the Dynatrac Free-Spin bearing replacement.)

South Bend Clutch

Ford’s factory clutch exploded after only 60,000 miles. We replaced it with a HD South Bend Clutch, pressure plate and throw-out bearing. There had been an annoying tendency for the clutch to grab. We replaced the factory clutch slave cylinder and its hard plastic line with the South Bend unit that features a flexible stainless steel line. The problem instantly disappeared.

The ZF six-speed manual transmission and two-speed transfer case are not as smooth as our old four speed in The Turtle III or the five speed in The Turtle IV, but now, with a hard 200,000 miles on it, we should not complain. We never used the PTO option. A periodic oil analysis of all the gearboxes has shown that there is no unusual wear in the transmission.

K&N Breathers

Thanks to highly mounted K&N breathers on The Turtle II, we had no problems crossing this flooded two-track where beavers had decided to dam a creek in the Upper Peninsula Michigan.

Where possible remote K&N breathers on gear boxes and differentials were added to keep water out during river crossings or beaver ponds.

Deaver Springs, Rancho and Hellwig

Custom suspension has been designed by Deaver Suspension to carry our anticipated fully loaded weight of 14,000 pounds, all the time. No overload springs. All our Deaver Spring packs feature a full “military wrap” and have Teflon pads between leaves for smooth flexing. Dual adjustable Rancho RS9000XL shock absorbers in front set on #3 and single adjustable RS9000XLs set on #6 at the rear have shown to be reliable under the harshest conditions. Adding Hellwig Air Assist bags at the rear softens the ride and Hellwig HD sway bars front and rear improve stability and cornering.

The Turtle V carries 94 gallons of Diesel thanks to Transfer Flow’s two tanks

Our factory fuel tank was replaced with a custom Transfer Flow tank with a 46 gallon capacity and an emergency drain plug if we should get a bad tank. Transfer Flow also installed their 38 gallon auxiliary tank and designed a special switch-over valve so we can choose which tank to run from. Those two tanks along with our two 5-gallon jerry cans give us a total of 94 gallons of diesel, or an easy 1,000-mile range. If there is a road anywhere in the world 1,000 miles long, there will be diesel somewhere, or it wouldn’t be a road.

Racor and Airtex

An auxiliary Racor fuel filter/water separator/fuel pre-heater with a clear bowl allows inspection for dirt or water in the fuel before it even reaches the Airtex fuel pump.

: The front differential is a heavy duty Dana 60 fitted with an ARB Air Locker and protected with the Dynatrac Pro Series off-road differential cover.

: The rear axle holds a massive Detroit 135S fitted with a Detroit Truetrac limited slip.

: Where possible remote K&N breathers on gear boxes and differentials were added to keep water out during river crossings.

: Thanks to highly mounted K&N breathers on The Turtle II, we had no problems crossing this flooded two-track where beavers had decided to dam a creek in the Upper Peninsula Michigan.

: With less than 60,000 on The Turtle V, the factory clutch destroyed itself. We replaced it with a South Bend including pressure plate and throw-out bearing.

: Ford’s factory clutch exploded after only 60,000 miles. We replaced it with a HD South Bend Clutch and throw-out bearing.

: The South Bend clutch assembly and throw out bearing are ready to be installed.

: It only made sense to change the throw-out bearing at the same time.

: We replaced the factory clutch slave cylinder and its hard plastic line with the South Bend unit that features a flexible stainless steel line. The problem instantly disappeared.

: The inflexible hard line hose that Ford installs was causing clutch release problems. It was removed.

: The South Bend slave cylinder kit unit that features a flexible stainless steel line is much easier to install.

: Deaver’s 15-leaf custom spring pack is designed to carry a full load and flex smoothly. There is no “overload” spring.

: All our Deaver Spring packs feature a full “military wrap” and have Teflon pads between leaves for smooth flexing.

: Hellwig HD sway bars front and rear improve stability and cornering.

: Dual adjustable Rancho RS9000XL shock absorbers in front set on #3 and single adjustable RS9000XLs set on #6 at the rear give a smooth and controlled ride.

: Adding Hellwig Air Assist bags at the rear softens the ride.

: A Transfer Flow custom 46-gallon main tank replaced the factory tank that was flaking a coating off on the inside.

: This is Transfer Flow’s custom main tank.

: In the process of designing a new main rear fuel tank Transfer Flow added a drain plug, important if we get a bad batch of fuel.

: Transfer Flow’s auxiliary 38-gallon fuel tank plus our two jerry cans on the back give us a total of 94 gallons of diesel or an easy 1,000-mile range.

: Transfer Flow’s auxiliary 38-gallon fuel tank fit comfortably between the drive shaft and our 5-gallon AccuAir compressed air tank.

: A Racor fuel filter/water separator/fuel pre-heater with a clear bowl to allow inspection for dirt or water in the fuel before it even reaches the Airtex fuel pump.