Welcome to Manins' truck camper project

Transfer Case

The Transfer Case sends power to the front and rear wheels in the torque ratio of 30 : 70. The Case contains the intermediate gear (from 1 : 1 to 1 : 1.3) and the low range gear (from 1 : 1 to 1 : 3) which is after the intermediate gear, so low-intermediate is 1 : 1.13 x 3 = 1 : 3.39.

The Case serial number is 6301579.


According to the makers of the Transfer Case, inlet maximum speeds to the Case should be limited to 4000 rpm in high range and 1500 rpm in low range, regardless of whether the intermediate gear is used.

The limits on input speeds to the Transfer Case are not mentioned by Iveco, and they are not so important for high range. However, they are a significant limit for low range where 1500 rpm can be exceeded in 3rd Gear at an engine speed of 3062 rpm (xx kph with 37" tyres).

Another issue to consider is maximum oil service temperature. This is set at 120oC — see Transfer Case. I have installed a temperature sensor to the lower outside of the Case to keep an eye on this, though it is really only an issue at high ambient temperatures and/or sustained speeds above 100 kph.

Transfer Case Bushes


Replacement Poly Bushes for Transfer Case. Inner sleeves but no outer.

The Iveco bushes used to suspend the transfer case under the truck are a "Silent Bloc" type that is of poor quality. The bushes crack and so become ineffective in centering the Case. The result is various clunks and rattles from takeoff, and upon changing gears. TT30 showed these symptoms at around 20,000 km. Iveco does not seem to be interested in addressing the issue, but others are. TravelTrucks sells a set of Poly Bushes that replace the OEM bushes and sleeves. These are not so effective at isolating the Case from the vehicle so there is an increase in low level whine, but they should last the life of the vehicle instead of less than 20,000 km.

To remove the outer sleeve of the OEM bush requires huge force. Iveco garages drop the Transfer Case and press out the originals using a hydraulic press. A facebook friend, David Luck, came up with a far better idea and I have followed it with success. He used a spindle nut pull and press sleeve kit set purchased from eBay seller vidaxl-au. This makes it possible to apply the necessary force while the Transfer Case is still connected to its drive shafts.


From the kit we use

  • the M16 pulling spindle and nuts
  • the 44 mm dia. Push/Pull Sleeve, turned down to 41.8- mm dia., as the push sleeve, and
  • the 60 mm dia. Push/Pull Sleeve as the receiving (Pull) sleeve.

The Transfer Case was unbolted and lowered sufficiently to give access to the OEM sleeves. These were pressed out, the Poly Bushes were lubricated with silicone grease and pressed into position. With the new inner sleeves pushed in, the Transfer Case was raised back into position and bolted in place.

Transfer Case lowered to give access to mounting bushes.

A view of the OEM bushes in the Transfer Case.

Access to the bush on the driver's side is rather cramped.

The rear sleeve halfway out. The 60 mm Press Sleeve is on the left, the 41.8 mm Push Sleeve is on the right.

The passenger side sleeve being pressed out. Looking from below.

A Poly Bush is pressed in the rear mount by an M16 spindle nut and large washer.

Some observations

  • Axle stands for the front axle are necessary to stop any rolling.
  • The M16 bolt holding the rear bush is shorter than the other two and these latter have a washer below the bolt head.
  • 24 mm AF but 15/16" AF spanners are a good fit for the M16 bolts and nuts.
  • The handbrake cable needs to be unbolted at the rear lever.
  • Two electrical connectors to the Transfer Case needed to be undone.
  • The Press Sleeve Kit is of high quality - the spindles are fine threaded and the nuts have ball-race washers to transfer maximum torque.
  • A lot of torque is required to start the sleeve removal - it gives way with a "pop".
  • The shiny end of each Poly Bush and the mount holes should be well lubricated with silicone grease.
  • A Poly Bush does deform as it is pressed into the mount hole. It is surprising how the end lip compresses and pops back into position when the bush is fully home.
  • Install the inner sleeve after the Poly Bush has been fully inserted.
  • The handbrake bracket that fits over the driver's-side bush mount bracket needed to be spread just a little before it would go back into position.

Update Jan17: TravelTrucks revised the suspension bushes after some reports of broken brackets. The revised bushes have a much thicker crush tube, so now they cannot be installed too tightly. Supplied under warranty, I installed them following the same procedure as already described.

20170802_081228 20170801_094237

Update Aug17: The drivetrain did not feel right — a roughness during acceleration and other symptoms. Looking at the transfer case mounts I noticed that the left side brackets on the cross-member were both broken and the transfer case was suspended on the fuel tank! The photo shows that the brackets had broken below the welds, presumably due to fatigue cracking. Even the revised TravelTrucks bushings were too inflexible, transferring too much vibration to the brackets. Fortunately the repair was accepted as a warranty claim. It took several hours to remove the existing cross-member without first removing the auxiliary fuel tank and a new cross-member was then installed. OEM bushings were installed in both upper mount holes on the transfer case. It will be interesting to see how long they last this time.

Low Range Circlip

I am aware that several Transfer Cases have failed, either because of overheating (high speeds, heavy towing loads) or because, apparently, the large diameter circlip that restrains the low-speed planetary gear cluster in place pops out and lets the gears fall loose in the Case.

I monitor the Transfer Case temperature and have never observed unduely high temperatures (maximum of 96°C on a very hot day).

The thought of the circlip popping out during or after using low range has been very unsettling, especially since the Transfer Case of a Daily in the same batch to reach Australia and owned by a good friend failed in the Victorian High Country. An opportunity arose to have the chap who knows most about the Transfer Case and how to fix the circlip, Don Incoll, do work on mine.


Magnetic drain plug (left) covered in steel whiskers, (right) cleaned up.

First task was to drain the oil; at 53,000 km, this was the first time this has been done. The magnetic plug was covered in steel whiskers but the oil was remarkably clean and a light honey colour.

Don removed the Transfer Case from the truck and set it up in a special jig. He then split the rear part of the Case away, exposing the low-range planetary gear block behind its cover held in place with the large circlip in the upper half of the rear case. The groove for the circlip was fairly deep and it took quite a lot of effort to remove the circlip, suggesting to me that this Case would not have easily failed in use.


Transfer Case S/N 6301579 out of TT30.

Case split apart. Upper rear part contains the low-range planetary gear cluster held in place with the large problematic circlip.

On the bench. Click image to see the circlip ends before chamfering.

It wasn't easy to remove the circlip. It appears that the clip had been expanded by hitting the inner sides in several places.

The rear case was set up in a milling machine.

A flat was milled into the case to take a holding clamp for the circlip, which had both ends chamfered the same way.

The prepared holding clamp. When installed it keeps the circlip fully expanded so it cannot jump out of its groove.

Circlip and clamp in position in the rear Case.

Transfer Case assembled and back in position. Lots of cleaner, sealant and thread locker were used beforehand.

I now have the peace of mind to know the Transfer Case will not fail because the circlip popped out.