Dual Transfer Case for Hilux - Page 2

Article by Andrew, you can follow the topic by clicking here.

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OK, so on with the show. My parts finally arrived end January just before I had to go to Germany, so I spent the whole time wishing I was back

I must say, a very comprehensive kit of parts, nuts, bolts, seals and gaskets etc. Here are some pics of what I got

ll the nuts, bolts, seals etc, and top shift conversion kit

Here's the adaptor, very well made and machined

and the 4.7:1 gear set for the rear transfer box

Also got a whole selection of gearknobs for the twin stick conversion kit and front crawl box high low selector. This is how they come, made from good quality rubber

But, these look a bit boring and you can't really see the lettering so easily, especially when you have 4 gear sticks in the vehicle

So, I painted the inlay to make it stand out better

Last night I built the crawl box up into the adaptor. I won't go into all the details of assembly here, but Trail Gear's web site had excellent instructions and video clips if you are interested.

First I had to weld a piece of key stock onto the existing high low shift rod so the high low gear stick cannot slip out.

Then I assembled the existing 2.28:1 gearset from the donor transfer case onto the adaptor.

Closed up the box and installed the shift rod into the shift fork, all done

So now I need to make some time to start stripping the Hilux's transfer box and prop shafts. will have to dodge SWAMBO a bit...

This afternoon I started work on stripping the Hilux. First up was to remove the interior seats and vinyl mats so it will be easy to work when I need to cut the floor pan for the extra gear sticks.

With that done, I removed the front and rear prop shafts, then put a jack under the transmission to support it. Next to be removed was the cross member. The original one is quite light compared to the heavy steel plate that will replace it. I will have to find some other things to remove to compensate for the weight gain

Next, drained the oil from the transfer case, disconnected the 4WD switch wiring, speedo cable and removed the Low range gear stick.

I then lowered the transmission on the jack as low as I could so I could get access to the two top bolts which hold the transfer case to the transmission.
This is a really tight fit and you only get about one click of movement on the socket ratchet. Luckily all the bolts came loose easily. For the middle two bolts you need a universal joint on your socket to get access to the bolt heads.

With the bolts removed, I tapped the transfer case a few times with a rubber mallet to seperate it from the transmission.

I then lay on my creeper with a piece of wood on my stomach and pulled the transfer case and 4WD section off and onto my stomach and slid out from under the Hilux to see SWAMBO staring at me with that expression. "You just drove it this morning, so why is it now in pieces "

And finally the transfer case out and ready to have surgery tomorrow... 5 hours well spent

Got busy again at lunch time today and worked until 7 PM tonight (Andy, you can calculate the efficiency if you want )

I stripped the transfer case and 4WD section right down to the indiviual components, sorted everthing into containers and then went and washed all the housings with engine cleaner to get rid of the old oil and road grime.

Got busy again at lunch time today and worked until 7 PM tonight (Andy, you can calculate the efficiency if you want )

I stripped the transfer case and 4WD section right down to the indiviual components, sorted everthing into containers and then went and washed all the housings with engine cleaner to get rid of the old oil and road grime.

With all the housings cleaner now, I then took the low range transfer casing and using a small angle grinder ground away some of the casing at the bottom and also some off the oil galleys to clear the bigger new 4.7:1 gearset.

I used a red permanent marker to colour in the inside then test fitted the gears to check where it caught on the housing. Quite an easy job.

Here is the housing after all the clearancing work was completed

I then stripped the rear main shaft to remove the old 2.28:1 main gear and replace it with the new 4.7:1 main output gear.

I then assembled the transfer case and installed the top shift conversion kit, which changes the forward shift transfer box to a top shift box (gear selector collars in the transfer box). This alows the fitment of the twin stick selector gear sticks. The rear box has to be top shift to work.

Here you can see the selector rails with the shift collars in the transfer case

I then test fitted the twin sticks to check that the gear selection worked OK. No problems. Next I fitted the studs to the rear case, fitted the gasket and some Loctite Ultra Grey silicone and mated the rear transfer section to the front crawler box.

A word of warning here, which is not mentioned in the very detailed instructions: When mating the adaptor plate of the front crawler box to the rear transfer case, push the case onto the studs until about 5mm of the studs protrude through the adaptor plate. Then, place the washer, spring washer and nyloc nut onto the stud, then tap the two casings together turning the nut to take up the protruding thread of the stud as the housings are moved together. WHY?? because if you look at the picture below, you'll see that if you don't, the two nuts at the bottom will foul each other and there is no way you'll get the nut on with the casings mated together.

Here is the whole dual case system assembled as far as I got tonight

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