Tuesday, March 20, 2012

Transfer Case, Part I

Now with the transmission case relatively complete (waiting to add gaskets until the last moment prior to mating it with the transfer case and engine), it was time to pick out one of my half a dozen transfer cases to clean up.  My five year old son, Jack, will very simply tell you that the transfer case make the jeep go in four-wheel drive.  He is my secret weapon and when I get confused, he dumbs things down so even I can comprehend the most complicated theories.   One day, he and I were chatting about some old theory of Einstein's while enjoying a cup of coffee.  He pointed out to me...sorry, I am getting WAY off track right now.

Anyhow, I thought a Dana 18 transfer case was a  Dana 18 transfer case no matter when it was built (during the war or postwar).  Ha!  I have been somewhat educated in the last week or so.  Although the systems are the same, they are different.  Two major areas of difference are the postwar units had an upgraded Intermediate Shaft (went from .75" WWII to 1.25" postwar).  Also, the beefier T90 postwar transmission was structured slightly different from the WWII T84 unit.  The T90 did not need the critical golf pencil sized Interlock Plunger to rest between the transmission and transfer cases.  So, the postwar units did away with cutting out the channel in the transfer case for the Interlock Plunger to ride in. 

Well, I have several transfer cases (all needing to be refurbished!) sitting around the property, so I really liked my odds of finding the correct WWII version.  In the end, I had two; one still sitting in a dilapidated jeep in the yard and another sitting in the shed.  The one in the shed was easier to access so I opted for that one.  It originally came from the $150 crap jeep I bought locally.  But it is the GPW (Ford) case!  That is a small chunk of gold to me.

The first step in rescuing the transfer case was to disconnect it from the T90 transmission it had been mating with for 5o or so years.  I popped the rear cover off of it, finagled the cotter pin out of the large castle nut on the mainshaft.  For some reason, my 1 1/4" socket was not working.  I drenched the nut with penetrating oil and went to buy a larger socket.  In the end, I used LOTS of penetrating oil, flames, hammers, chisels, screwdrivers and some muscle spread over a week or so, but the darn nut would not budge.  It was rusted on to stay. 

I ended up taking a page out of Bubba's book.  I strapped the transfer case to my trailer, wedged a piece of steel into the gears of the transmission (to stop them from spinning), connected my socket to a breaker bar, stuck the breaker bar into an old fence pole and hung my fat ass off of the pole until something broke.  "Something" was either going to break, as in unfixable, or the nut was going to "break" loose.  I got lucky.
In all regards, this SHOULD work.  Seriously, my muscle with Jack's brains?  Easy.

Struck out with Jack, so I would I was flat out grasping for straws.
Here is the big hunk of steel wedged in the transmission to stop the gears from spinning.
 I wasn't too concerned breaking the gears.  It is a T90 transmission and I have a few of these (that I do not need).

Here is how I actually got the nut to budge.

Now that I got the transmission and transfer case separated.  It was time to disassemle the case, take inventory, order replacement parts and clean all of the usable materials up.  Let's do this.

Here is the the transfer case with the major componets that I will be referring to labeled.

Rear view.

Front view.

Internal view.  You can see the gears of the Intermediate Shaft.

Front output cap and shaft (bottom left) and bottom access plate (bottom right).

Rear view.  Output shaft and the parking/emergency brake.

Parking/Emergency brake unit.

Internals.   Output shaft (right) Intermediate Shaft (center).

Inside the Main Output Shaft cap.

The nastiness of the inside of the bottom access plate.
I used a 12 ton press to get the Intermediate Shaft out.  Funny thing, on the top of the case, there is a data plate from Brown/Lipe Spicer.  The case clearly has the Ford stamping on it.  This is confliction in the highest sense!  Turns out, the Intermediate Shaft was of the larger postwar variety.  My best conclusion was that the military sent the case back to Spicer after the war to have it modified.

After getting the Intermediate Shaft out, I could then turn my attention to the Output Shaft.  That one was a bit tricky.  I couldn't finesse it out so I turned to the manual to figure out the proper method.  Turns out you  need to beat the rear end of the output shaft with a mallet.  It would then break through the races and cones of the front side and give one room to manuever.  Wow.  I never would have guessed that!  I accomplished this feat, although somewhat skeptically.  The last obstacle was a rinky-dinky little snap ring.  I ended up spreading the snap ring too far and snapped it two.  Luckily, when I was ordering my new parts, I had enough forward thinking sense in my brain to ordered a spare.  Actually, Jack told me to do it.
Output shaft on its way out!

Cleaned and primed main case.

Compare and contrast of the gears.  Can you guess which one I have cleaned?
I ordered $175 worth of replacement parts.  This consists of all of the bearings, seals, cones, races and a few other little parts.  Luckily, nothing of major importance was ruined on the inside.  Everything that is being replaced SHOULD be replaced after 60 years of use and abuse.  When the new parts arrive, I will take apart the other assemblies (front and rear caps), clean them up and then rebuild them.  For now, I am just going to clean up these parts that I am going to reuse...and wait!

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