H42 and dual transfer cases into an 80 (1 Viewer)

[BamaPaul]

OK I have been putting this off for a long time, but I finally got all my thoughts together and wrote this up.



To start off with I found a donor late ’85 FJ-60 to take all the parts from. These parts included:
· H42 Transmission with spacer
· Splitcase
· 3F bellhousing
· Clutch pedal
· Slave Cylinder
· Cross member
· Front and rear drive shafts (I just got the ends that attach to the splitcase)
· The hydraulic lines for the clutch
· Boots and shift arms
· Shift linkages
· An extra split case and transmission that was laying around


The other things I got for the project:
· 1” Body Lift
· Marlin ToyBox
· Clutch pedal bucket (these are different from the 60 to the 80 and have to be either custom made or bought from an overseas version)
· HD Transfer case mount from 4xInovations
· Lots of bolts from Fastenal they have to order the m12x1.25 bolts so it takes 1-3 days to get them in
· Gasket kit for the transmission and split case
· Red RTV
· 1.25” Drive shaft spacer for the rear from 4Crawler.com
· 3/8” heim joints and all thread (to make linkages for the split case)
· 16 gauge steel (to cover the transmission hump)

 

[BamaPaul]

The Body Lift was the first thing to go on since I can keep driving and wheeling the 80.
Next I put on the clutch pedal bracket and the clutch master cylinder. This was a fairly easy project once I got the bracket from Bhammapping. There are 2 holes marked in the body for the master cylinder and there is a grommet in place for the shaft of the master cylinder so any wiring that you have run through that grommet needs to be removed.



Once you drill the 2 holes you can line up the master cylinder and drill the other 2 holes for the pedal bucket.

 

[BamaPaul]

Master Cylinder installed

 

[BamaPaul]

Now its time to start assembling the tranny/toybox/splitcase combo.

Tearing the transmission and transfer case apart is pretty easy but you have to know which bolts to pull. There are 4 bolts holding the split case onto the transmission on the outside of the case itself and another 3 bolts holding it together inside the split case. So pull the 4 outside bolts then pull the 12-15 bolts that hold the 2 halves together and pull the 3 bolts holding the front half of the case on. To get to one of the bolts you have to pull a bearing.

This can all be found in other threads but I did attach a picture of the H42 with spacer so you can see which one will fit best in the 80 series.

 

[BamaPaul]

After pulling the split case from the transmission you can start installing the Marlin toybox. The parts from Marlin are MC23 and MC24 and the 4.7 gears if you’re into that sort of thing. I bought me toybox already ready to go with the 4.7 gears. The MC 24 is built in 2 halves one half mates to the mini truck transfer case half and the other half is attached to the transmission.


The back half of the mini truck case has the MC 23 adapter on it this allows it to mount to the split case.
Now for the hard part of the install, its not really hard it is more of a cringe moment, cutting the transmission output shaft. Measure the distance on the front side of the mini truck case and then transfer the measurement onto the shaft.


Measure again then measure again and then start to cut, I kept the sleeve on the shaft so that I could get a good vertical uniform cut from the get go. Then start the cut.

 

[BamaPaul]

The clearance is tight, so I used the cut piece of the shaft to help judge how much needed to come off.
The bearing in the above picture is interfering with the plate on the front of the mini truck and after reading repeated threads on installing the toybox I found out that Marlin doesn’t intend for that bearing to stay in place on the H55 but there wasn’t a definitive answer that I found for the H42 with the spacer, I dropped a line to Brendan at Marlin to find out if that bearing should stay or go. I also had to source 7 m12x1.25 bolts that are 115mm long they can be found at Fastenal.

 

[BamaPaul]

I tried to contact Marlin via email and phone after 4 days of waiting for an email response and getting there busy message when I called I decided to remove the bearing and press on hoping I would hear from them before it goes in the truck. After taking out the bearing the interference issue doesn’t exist and the toybox slides into place.


The next hiccup is the nipple machined into the back of the toybox that I assume allows the shifter mechanism inside to move far enough. Its not a big deal you just have to clearance the front side of the split case.

 

[BamaPaul]

Now its just putting the split case together. If you are using the H42 with the extension you will need to get some new bolts that are shorter to mate the split case to the toybox.

To make putting the split case back together easier be sure to put it into 4wd so that the gear is held into place by the front output shaft. Per the FSM make sure the gears are on the front of the case and slide everything together.

 

[BamaPaul]

All of this took about 2 weeks worth of time from 5pm to 9pm getting everything set up and ready to go into the truck. One nice thing now is that the split case is attached to the toybox and the toybox is divorced from the H42 via the adapter plate. That means that they can go in as separate units, H42 first then the Splitcase and toybox next. This makes it a pretty easy job compared to dropping the H42 and split case at the same time. Another thing to do now that I didnt do is build/buy a twin stick setup. Its not hard and it will save you a ton of time and headaches later.

 

[BamaPaul]

Now its time to throw all of this in the truck. It took me by myself a very full weekend to put the transmission, split case, toybox, and rear driveshaft in so that I could drive it Monday morning. Since then my brother and I dropped the whole setup again to change to a new H42 with a better 2nd gear synchro, it took a lot less time and was much safer with 2 people.

 

[BamaPaul]

This is a pretty straight forward deal, but make sure you have a good transmission jack or really good cribbing because that auto tranny is HEAVY. This actually took longer to pull than almost any other part of the job it was nothing hard to do it’s just a lot of bolts and connectors.
With the Auto out you can bolt up the bellhousing and align the clutch, the good thing is now there is plenty of room to work with the transmission out of the way.

 

[BamaPaul]

With the body lift the clutch slave cylinder clears with about ½” to spare. I went ahead and ran the original fj60 clutch line at this time. This gave me plenty of open area to fish the line down and find a good mounting point.

Lining up the transmission would normally be a pain since the tranny and transfer case have to go on as a unit or you have to put the split case together under the truck, but with theToyBox in there the transmission/transfer case will go together as 2 separate pieces. So I hung the transmission on the back of the engine and then bolted the ToyBox and transfer case to it. Now its time to brace this set up to the frame.

 

[BamaPaul]

I have 3 different cross members one 80(bottom), one 60(middle), and one 40(top).

What I found when I got done was that my original FJ 80 cross member lined up perfectly with the bottom of the ToyBox and that the ToyBox has the original cross member mounting holes from the mini truck on it. But that none of the 3 styles of cross member mounts I had would fit it. I had a mount from my fj80 from the donor fj60 and from the other transmission + splitcase that had been thrown into the deal, I assume it was for an fj40. So I ordered the Heavy Duty replacement from 4xInovations http://4xinnovations.com/p-TCC1322.html and it was at my house in 2 days. This thing is pretty beefy fits perfectly and cost less than one from Autozone or Advanced. The same mount fits the 4 cyl mini trucks from 79-95 so if your finding parts in a junkyard these should be plentiful but not nearly as well built.

 

[BamaPaul]

When the mount was bolted to the case there was a bit of a gap, but nothing a flat washer wouldn’t take out. With everything bolted up the front drive shaft flange is close to the cross member but has enough clearance to run without problem.

 

[BamaPaul]

Before you drive it there are a few things that have to be taken care of. You need to bypass the neutral safety switch

and hook up the reverse lights(yellow and red wires may have stripes I cant remember)

These will be in the main harness that is left in the engine bay after you take the auto tranny harness off of it.

I originally had the NSS jumped in order to get it running but I have since go the cruise control working and this requires the NSS to be open. So I am trying to find a good switch to go behind the pedal as Mr. T would have intended but have a switch in the dash for now to open the NSS while the cruise is engaged and close it when I start the truck.

 

[BamaPaul]

***DON’T FORGET TO PUT IN ALL OF YOUR FLUIDS***
Now you can drive the cruiser around and make sure everything is good to go

 

[BamaPaul]

I went with a very basic interior covering the transmission hump with 16 gauge steel and then painting it black to blend in some. I also used some Gylon rubber gasket material below the steel to dampen rattles and other sounds.

I have since put some sound deadening on the hump and covered it in carpet to quiet things down a bit. The boots I used are from the 60 for the transmission shifter, a mini truck for the toybox shifter and an ebay special for the twin stick(not shown I was still being stupid and trying to work with one stick). I actually used an old pizza box from lunch that day as my template for cutting the steel and getting my holes to line up.

 

[BamaPaul]

The last thing I did was build the front drive shaft. There are several write ups on the net about building your own shaft, but what you need is a steady hand, a ziz wheel, a good mig welder, your original front driveshaft and the flange from the 60 series that mounts to the split case. You ziz wheel off the original transfercase flange and then weld on the new 60 series flange in its place. My front shaft was exactly the same length as the old shaft, but I would double check with your setup to be sure.


The rear shaft fit but was a little more extended than I liked so I ordered a 1 ½” driveshaft spacer to go back there.

 

[BamaPaul]

Some other things I found that are interesting is the size of the 2 transmissions. The auto and stock transfer case are the same length as the H42, Split case and toybox. The Auto tranny setup was heavier than the new setup too.

 

[BamaPaul]

H42s are cheap I got everything to do the basic swap for ~$500, all off of one donor 60 series. The toybox is not cheap ~$1800 plus shipping and they are rare as hens teeth. An H55 would be nice to have so that I could have an Overdrive, but they are a lot more expensive ~$1000-1500. The RPM difference is minimal between the H42 and the Auto Tranny. I took 2 pictures one before the swap and one after, the cruiser is on 33’s in both shots and you can see that there is only about 600 RPM difference. First gear is much lower in the H42 than in the Auto and I could really stand to go up to 37’s anyways