Old Version MC07 |
Crawler
Installation Kit from Marlin Crawler (MC07 or better recommend). Note:
Speedometer extension isn't included in the kit. It is an optional
accessory you may need to purchase when installing a dual crawler in 1984
and later vehicles. |
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A Donor
Toyota Mini Truck Gear Driven Transfer Case. Note: The donor case that is
being turned into the crawl box in this example is from a 1985 remote, or
forward shifting transmission (G-52). You must make your crawl box out of
whatever style will fit your existing transmission. HOWEVER, you must use
a top shifting reduction box for your rear-most case. (Forward shift to
Top shift conversion kits available from Marlin Crawler) |
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| Disassembly of
donor transfer case: |
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Shift case in
to 4wd high range. (Both shift rods extended all the way forward. If you
forgot to shift into 4-hi before removing the transfer case you can just
pull the rods forward by hand.) |
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Remove rear
output flange nut using a 30mm socket. This is easily done with an impact
wrench. If you don’t have an impact you can use a couple driveline bolts
through the flange and a pry bar to hold the flange from rotating while
you are using a breaker bar with the 30mm socket. Remove Nut, Washer and
Flange. Note you do not need to remove the front output flange, just the
rear. |
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Remove the
(10) rear facing 14mm bolts (the ones with the number 6 on them) that hold
the rear split case together. There is no need to remove the (7) double
notch bolts that hold on the tear drop rear output cover. |
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Once the (10)
bolts are removed, it should look like this. |
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With a dead
blow hammer lightly tap on the 3 cast tabs to split the rear case. |
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Slowly and
carefully remove the rear case and set to the side. |
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Slide the
Speedo Gear off the main shaft and be careful not to loose the 1/4” dia.
detent ball. This ball can be removed from the shaft using a small magnet. |
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Slide the Oil
slinger gear off the main shaft. |
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Remove the
rear main shaft bearing. |
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Remove
2wd-4wd Shift Hub. |
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If you look
at the Shift fork you will notice that the 3/16 diameter spring roll pin
that holds the fork to the shaft is not accessible. |
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Shift the
passenger side shift fork backward (to 2wd high) to expose this 3/16
diameter roll pin. |
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Remove the
3/16 dia roll pin from the shift fork using a small punch and a hammer. Be
careful not to loose the pin in the case. You don't have to drive the pin
all the way out, just enough to slide the shift fork off the shift rod
will do at this time. |
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Slide the
2wd-4wd shift fork off the passenger side shift rod, the shift collar will
also now be able to be removed with the shift fork. |
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Now you can
slide off the front wheel drive gear from the main shaft. Be careful not
to loose the second 1/4” dia. detent ball. |
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Note there
will be (2) needle roller bearings on the ID (Inside Diameter) of the
front wheel drive gear and a thrust washer behind that. |
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Remove the
(2) stamped steel oil galleys. Observe and remember how they were
installed. |
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Remove the
(4) 12mm (??) double notch bolts that hold on the cast retainer and set
the retainer to the side. |
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Remove large
snap ring on OD (Outside Diameter) of 6308 bearing. |
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Remove the
(2) shift detent plugs using a 6mm allen wrench. (If the hex head holes
are packed with dirt clean them out so you can get a good grip with the
hex wrench or you run the risk of stripping the holes out.) |
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Using a small
magnet remove the spring and 5/16" ball bearing from the driver side. |
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Using a small
magnet remove the spring and 5/16" ball bearing from the passenger
side. |
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Remove
passenger side shift rod. You may need to turn it 90 degrees (quarter
turn) as you pull it out if the interlock pin is trying to hold it in
place. |
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Now that the
passenger side shift rod has been removed, you can now remove the shift
interlock pin (its pill shaped) that is between the two shift rods. You
will need to use a magnet in the passenger side detent hole if it didn’t
already fall out. |
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Here's a
virtual view of how the shift rods, detent balls, springs, and shift
interlok pin are assembled in the reduction box. |
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Now you can
remove the remaining (2) 14 mm bolts (the ones with the number 6 on them)
that are rear facing. |
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Turn the case
around and remove the last (2) 14 mm bolts (the ones with the number 6 on
them) that are forward facing (next to the front output flange). TIP:
These two bolts are often the cause of an annoying leak in the transfer
case. Many transfer cases came with a stone shield around the CV joint on
the front driveshaft. If you remove the CV shield bracket these two bolts
which the shield was mounted to will be too long and will bottom out
before they clamp the case halves together tightly enough to prevent a
leak. You either need to shorten the bolts or just run a washer under each
bolt head to make up for the missing thickness of the stone shield
bracket. |
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With a dead
blow hammer lightly tab on the cast tabs to split the rear housing from
the reduction box. Slowly and carefully remove the rear housing. |
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Set the
reduction box to the side. |
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| Removing
factory main shaft: |
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With a dead
blow hammer very carefully tap while supporting what’s left of the main
shaft assembly out of the rear housing. |
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Set the rear
housing to the side since you will no longer need it. |
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Remove the
small snap ring from the main shaft that holds on the 6308 bearing. |
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Using a
bearing splitter and a press carefully press off the 6308 while supporting
the 11” long main shaft and the 37 tooth (2.28) low range main gear. |
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Here's the
setup that we use with the Harbor Freight 20-ton press. |
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Remove the
6308 bearing and thrust washer and the third 1/4" ball bearing. |
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Remove the
main gear (finally) and needle bearing from the main shaft. The main gear
is what you need for the crawler, so you can set the rest to the side. |
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| Welding the 'Keystock'
to the Shift Fork:
Now is a good time to deal with the shift
rod. Depending on what tranny you have, you may need to convert the
crawler to have the correct shift rod for the tranny that its going
behind. The forward reduction box (crawler box) may be top shifted or
remote shifted as long as the tranny that its going behind is a remote
shifting tranny. The rear box must be a top shifting case. For our
application we need to convert our donor box to a short shift rod since it
was going behind a remote shifting W56. And the rear transfer case we
acquired a top shifting case that was behind a top shifting W56. The folks
at Marlin Crawler can help you determine what you need if your not sure. |
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Remove the
(4) 12 mm bolts that hold the reduction box cover plate on. (This is where
your transfer case shifter would be if you have a top shifting case from
an 85-88 EFI W56 tranny.) (We forgot to take a picture earlier so this is
an "after-the-fact-to-illustrate-what-to-do" pic. Notice the
whole thing is assembled...) |
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Shift driver
side fork so you can see the 3/16 roll pin that is holding the shift fork
onto the shift rod. With a 3/16 punch carefully punch out the roll pin.
Try not to loose it in the case. If you do drop it, remember to get it
later. |
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Slide the
shift fork of the rail and remove the driver side shift rail and replace
with the correct one if necessary depending on your application. |
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There are two
lengths of remote shifting shift rods. The picture shows how the shorter
1990 W56 remote shifting t-case fork (top) compares to the longer 1985
G52/G54 remote shifting t-case fork (bottom). In our install we swapped
out a remote shifting G52 tranny for a rebuilt remote shifting 1990 W56.
Even though both cases were remote shifting we had to swap these shift
rods to get the 1985 transfer case shifter to work properly with the 1990
W56 transmission. (Shift rod lengths changed in 1989 due to transmission
changes, but all shift rods are swappable between all transfer cases from
1979-1995) With a quick call to Marlin Crawler, we got the appropriate
rod. |
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Weld the
supplied piece of ‘keystock’ across the ends of the shifter. Be sure
to clean the ‘dingle-berries’ off before reinstalling it. Also test
fit the shifter back into the newly created ‘box’ to make sure it fits
where you welded the keystock onto the shift rod. |
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A small piece
of scrap steel (1/4” keystock) can be used in place of the supplied
piece as long as the shifter can fit into the “boxed” area and it
doesn’t interfere with the gears or the case in the reduction box. |
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Slide the
shift rod back thru the case and the shift fork and reinstall 3/16” pin
thru the fork. (This is the same picture as shown earlier for removing the
pin so pretend the keystock is welded onto the fork in the picture.) |
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Reinstall the
(4) 12 mm bolts that holds the shift plate on. (we where able to reuse the
factory gasket) |
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| Assembly of
Crawler: |
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Now that you
got the main 37 tooth (2.28) low range main gear off the main shaft you
can start assembly the crawler. (The picture shows the complete main shaft
with the 6308 bearing and low range main shaft gear still attached and
needing to be removed.) |
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Apply a light
coat of gear oil onto the new main output shaft and slide on the 31 needle
roller bearing and main 37 tooth (2.28) low range main shaft gear which
you removed from your stock main shaft. |
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Place one of
the 1/4" dia. detent balls from the donor case in the hole on the new
main shaft and slide the new thrust washer on while aligning the detent
ball to the slot in the thrust washer. |
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Now very
carefully install the new main shaft assembly from above into the
pre-installed bearing in the MC07 Crawler adapter. |
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Install the
new large heavy duty retaining ring on to the end of the new main shaft. |
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We broke one
set of snap ring pliers and it took a lot of fiddling but we finally got
it. Basically I would recommend a GOOD HEAVY DUTY set of snap ring pliers
and an extra set of hands to install this snap ring because it takes a
good amount of force to spread the new heavy duty snap ring over the
shaft. |
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Then we very
lightly tapped the main shaft to seat the retaining ring against the
bearing so we could properly check the main gear oil clearance gap. |
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Then we check the oil
clearance gap between the main 37 tooth (2.28) low range main gear and the
end of the main shaft. It should be between .004” and .010”. Ours was
.006” so we continued. |
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Now install (5) of the (11)
studs into the reduction box with the short threaded end into the
reduction box. If you don’t have a stud installation tool, double
nutting with the supplied 14 mm bolts works just fine. We also used blue
loc-tite on these studs to prevent problems in the future. Tip: To
install studs using the double nut method simply run one nut down the
threads, then bring another nut down on top of the first. Tighten them to
EACH OTHER, then turn the stud into the hole using the TOP nut. When you
have torque the stud in tight, simply turn the lower nut down the
remaining stud threads. This will break it loose from the upper nut, but
not loosen the stud. Note: There will be one threaded hole in top
center of the reduction box that you do not install a stud in due to the
adapter plate covering the hole. Just hold the adapter plate up to the
back of the reduction box before you puts studs in to verify where the
studs are to be replaced. |
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Now pack the 8 needle roller
bearing with grease and install on the reduction box main shaft. |
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Clean the mating surfaces and
spread a thin layer of your favorite sealant (Permatex Ultra Black is what
I like) on the reduction box mating surface. Now very carefully align the
crawler adapter assembly onto the reduction box. This may take a bit of
time to align the shafts and gears to get it to slide on. Eventually it
will slide on. |
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Now install the supplied
washer, lock washer and nut on each of the five studs and tighten. Reuse
(2) of the original 14 mm bolts (the ones with the number 6 on them) and
install in the two extra hole to finish the main assembly. |
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Reuse the drain plug from the
donor case and install into the bottom of the adapter. (oil the tread to
prevent future galling. We decided to install one of the low profile drain
plugs here. |
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Reinstall the 5/16" dia.
shift rod ball, detent spring and plug into the side of the adapter. We
applied some sealant (Ultra Black) onto the thread to seal it. |
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Remove the 4wd shift position
indicator from the reduction box. |
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Now install the seal and plug
that is provided in the kit to seal the 4wd shift position indicator hole. |
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That completes the
assembly of the crawler. Remove the old transmission seal, install the new
supplied transmission seal, install the new supplied paper gasket using
"Hi-Tack" (black berry jam) or your
favorite sealer, and bolt the reduction box and crawler adapter to the
back of your transmission. |
| Preparation of
Rear Transfercase
This article is specifically about
assembling the crawler. If you got this far putting the back end on should
be painfully easy. But, just for giggles, here's the other stuff you will
need to do before you can wheel.
If your rear-most case came out from
behind a 1979 or 1980 4 speed, you will need need to grind the flared
spline area on the main 21 spline input shaft so it will flush up with
your crawler. Search Pirate4x4 or contact Marlin. This is kinda rare, but
does crop up from time to time. www.MarlinCralwer.com
If your rear-most case is out of a 1985
to 1988 top shifting EFI (W56-A/B) tranny then you must shorten the driver's
side shift rod. This is the shift rod sticking out of the rear most case
when you shift into 4hi that has the flat side on top. You must trim
1/2" off of the front of this shift rod to avoid jamming between the two cases.
Install final (6) studs into transfer case
Check operation of transfercase
Lengthen 4wd shift indicator light wire.
Install Speedo Extension if needed for your application (1984 and later)
Modify floorboard, driveline length,
crossmember and add 3 quarts of oil [80-90wt.GL5 gear oil] (2) for the
transfer case (1) for the new crawl box, as per Marlin's instructions.
Don't forget to re-fill your tranny if you drained it!
That completes the
assembly of your Marlin Crawler Dual Adapter
www.MarlinCralwer.com
(559) 252-7295 |
Tools
Required:
