Restoring GPW 14518

[17thAirborne]

One final inventory before beginning assembly. I should have done this earlier as I only gave the shifter forks and rails a preliminary look over. I missed the deep-ish scoring on both sides of the forks where they "ride" on the grooves in the gears. I read somewhere that comes partly from holding ones palm on the shifter and providing a side force on it while driving. That apparently caused the forks to ride against the grooves and wear out the forks prematurely. Somehow I left out the shaft lock plate GPW 7155. I still need to seat the shifter plate rivets in the cover. Will be getting an impact hammer and some rivet anvils for that job. Should come in handy.

In any case I will need to order a few more parts. That's a good thing as my wife loves checking the mail and proclaiming "parts is parts" when the goodies arrive.

I am enjoying the meandering pace of this assembly, but I have my hands in so many other things GPW related and am trying to restore a Cavalier C-51 coke machine from 1951.

[17thAirborne]

From : TM 9-18038

Here are the Transmission Assembly Instructions I will follow, which I will supplement from comments in the G and John Barton's Pages.

ASSEMBLY.
a. Install Idle Gear. Hold the idle gear (fig. 15) in place in
the case with the cone end of the hub toward the front, and push the
idle gear shaft into the case.

b. Inetall Countershaft Gear (fig. 14). Dip the countershaft
bearings into SAE 90 oil. Slide the spacer into the countershaft gear
and install a bushing in each end of the countershaft gear. Coat the
front thrust washer, rear thrust washer, and steel washer with a light
film of grease to hold them in place while installing the gear. Lay
the countershaft gear in the case with the large gear toward the front.

c. Install Mainshaft Assembly (fig. 13). Insert the mainshaft
in the case through the opening in the rear of the case. Slide the
first and reverse gear onto the shaft, with the shifter fork channel
toward the rear. Slide the second gear onto the mainshaft with the
tapered end of the gear toward the front. Install a blocking ring
onto the second gear. Slide the synchronizer onto the mainshaft with
the long end of the hub toward the front and install the snap ring,

d. Install Main Drive Gear Assembly (fig. 13). Place the other
blocking ring in the synchronizer and install the main drive gear assembly
in the case.

e. Install Countershaft. Raise the countershaft gear into position.
Making sure the three washers are in line, push the countershaft into
the case and tap the lock plate between the countershaft and idle
gear shaft (fig. 4).

f. Install First and Reverse Shifter Fork (fig 8]. Hold the first
and reverse shifter fork in position on the first and reverse gear, and
slide the low and reverse shifter shaft (short shaft) into the case
about half way. Drop an interlock spring and ball in the pocket
Press down on the ball and push the shifter shaft all the way in the
case. Line up the groove of the shaft with the shifter fork and install
the lock screw.

g. Install Second and Third Shifter Fork (fig 8]. Repeat the
same procedure as used in installing the low and reverse shifter fork,
and then push the guide rail into the case and through both shifter
forks.

h. Install Gearshift Housing on Case (fig. 17). Place the transmission
in neutral position. Lay the shifter shaft plate on the pivot
and on the shifter shafts. Lay the spring washer on the pivot. Place
a new gearshift housing gasket on the case. Place the shift lever in
neutral position. Lay the housing on the transmission and install the
four lock washers and cap screws in the housing

i. Install Clutch Release Bearing (fig. 3). Slide the clutch release
bearing assembly onto the main drive gear bearing retainer and install
the clutch release bearing return spring.

[17thAirborne]

a. Install Idle Gear. Hold the idle gear (fig. 15) in place in
the case with the cone end of the hub toward the front, and push the
idle gear shaft into the case.

JB: "Then idler gear…cone end toward front, Insert shaft from rear…pay attention to notch on
shaft…the notch must line up to accept locking plate.. And this small shaft is harder to turn when all the way in.. The locking plate will do a final line up.. but easier to set it close now."


John installs his idle gear after the cluster gear. I have read both ways. I used a bit of Mogul Assembly Lube on the shaft to provide initial lube for the gear. It spins easily on the shaft, but not with lateral play. This is a new shaft and NOS gear. The cone is installed forward.

[17thAirborne]

b. Install Countershaft Gear (fig. 14). Dip the countershaft
bearings into SAE 90 oil. Slide the spacer into the countershaft gear
and install a bushing in each end of the countershaft gear. Coat the
front thrust washer, rear thrust washer, and steel washer with a light
film of grease to hold them in place while installing the gear. Lay
the countershaft gear in the case with the large gear toward the front.

JB: "The earlier section had pics of the index pin and front notches and how to set etc..tilt the gear so back end goes out rear bearing hole.. Level it off, line it up, and lower… it will probably take a few times…the fit between washers is slim, I usually knock them off a few times before I get it right. Let it drop to the bottom. Sometimes the fit is very tight…I have had to play with different combinations of thrust washers etc.. I did measure the thicknesses once....there were several variations. I have lapped them down.. and cleaned up the case surface if necessary. When I do get it to set right.. I test fit everything by using this Sears rolling pin pry bar as a substitute mainshaft.. hold gear with one hand…raise it slightly and slide bar in.. I roll the gear, get grease spread out to hold washers.. From now on…try not to turn case to much…you want the Thrust washers to stay in place.. The manual says put the idler in first…I find it easier to put the cluster assemble in first."

Oz-way: I selected the correct combination of washers (as outlined in post way above) that would give me a bit of movement.

.
.
1.I used some heavy grease to tack the front and rear thrust washers to the case ensuring the tang was in the grove in front and the pin inside the index hole on the rear. I also lubed the bearings.

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2. I lowered the cluster gear into the case letting it set on the bottom
3. I slid the counter shaft into the hole only enough to secure the rear steel washer.
4. There is just enough space to slide the bronze washer in place from above between the back of the cluster and the steel washer. I pushed the shaft farther in to "catch" the steel washer, and then nearly all the way in to catch the front washer ensuring the tang was still in the grove.

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5. I measured the fore/aft movement at 0.003" I suspect that will increase over time.

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Now I can replace the countershaft with a long Phillips screwdriver shaft for the next step

[Raflad]

Great thread, following with interest as my transmission will need a rebuild once I've finished the frame. Just drained the water out of it yesterday, thought they would have used oil

[17thAirborne]

Great thread, following with interest as my transmission will need a rebuild once I've finished the frame. Just drained the water out of it yesterday, thought they would have used oil

Thanks. You know water is cheaper. I should go that route. I am planning on using GL-1. Tractor Supply sells a product called Ford Transmission oil GL1. I read a lot about the differences between GL4,5 etc and decided to just go traditional. What are you planning on using for oil.

[Raflad]

Haven't thought about it as it's going to be a while before I get to that stage. I did pick up a copy of Robert Notman's book on rebuilding the T-84. Looks good.

[17thAirborne]

Haven't thought about it as it's going to be a while before I get to that stage. I did pick up a copy of Robert Notman's book on rebuilding the T-84. Looks good.

Its been recommended by several. I should do the same.

[17thAirborne]

c. Install Mainshaft Assembly (fig. 13). Insert the mainshaft
in the case through the opening in the rear of the case. Slide the
first and reverse gear onto the shaft, with the shifter fork channel
toward the rear. Slide the second gear onto the mainshaft with the
tapered end of the gear toward the front. Install a blocking ring
onto the second gear. Slide the synchronizer onto the mainshaft with
the long end of the hub toward the front and install the snap ring,.

JB: "The next part to go in is output shaft…book says Insert from rear of case and slide gears on..It is easier to put gears on and them slide whole assembly in. One of the gears that goes on output shaft is synchro.. the directions in different places are not quite clear on how to do this..You need the springs in.. Locking plates in place, outer hub on.. Some instructions use a clock system, or put in one, turn it over And do same thing, etc.. The easiest explanation of springs is this picture above to the left. Hold the plates with your fingers and slide outer hub over..a little oil helps. Outer hub should slide back and forth.. you’ll see action of plates and springs, the next picture shows various types of locking plates I’ve seen short, curved, long and flat…I have come across many.. I think it is just important to have three matching ones.. You should always buy a new synchro and blocking rings.. the first/reverse gear goes on output shaft, fork channel to rear then second gear. taper toward front.. it only goes on a short distance . Then blocking ring..the small brass gear.. Then synchro…. Long end of hub toward front line up notches in blocking ring with plates on synchro.. put snap ring in front of synchro.. slide gears toward front.. tilt and put back end of assembly out rear hole in case.. just let it sit there..Now assemble the input shaft bearing with snap ring goes on…shielded side toward the case, the snap ring holds it on…"

OZ: Here is an image of the clutch hub and components. Note the orientation of the springs and the fact that there is a deep side and a shallow side. John calls the deep side the long side. Place the long/deep side forward.

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The next image shows the location and orientation of all of the parts on the Main Shaft. Note the front snap ring is loosely hanging for the photo, and the spacers and baffle are just slid on to show the orientation and alignment. Also note that the closed end of the rear bearing should be in toward the transmission case, open end on the outside. Which is not what I am showing!!!

[17thAirborne]

Just some observations:

The spacer ring is 0.180" thick. RFJP sourced
The snap ring is 0.080" thick. RFJP (The original one is 0.090")
The gap between the snap ring and it's groove is 0.034" Note the feeler gauge between the ring and the groove.

Is this a concern???

[17thAirborne]

I have watched T84 shim and spacer videos until I want to puke. I have read over 2 hours of posts on the spacer issues. With all the arguing about shaft movement yes or no etc, I pose an initial simple question that has me confused.

Please forgive me, this is my first T84 and I want to get it right and record for other plebes like me who follow.

I have new gears, new blocking rings, new hub and dogs CROWN made.

It has to do with gap/slop/spacing between the components in the image, namely between the hub, the hi/inter gear and the low/rev gear.

Do I have to measure anywhere at all?
If so, where do I measure?
What is good and what is bad?

[17thAirborne]

I just noticed something else. The Shifter Plate Pivot Pin is missing. I have the hole in the top of the case, but no pin. The one in the original case is there, but will not budge. Need heat I guess. I don't see them for sale either.

[17thAirborne]

I don't see anywhere to purchase the pin, It is not in the parts catalog.

The pin measures 0.375" in diameter. Its hard as s#!t so a hardened steel 3/8" dowell pin should work. It sits out from the old case by 0.200" and the recess in the NOS-ish case is 0.525" deep at the sides, then with the drill profile, it's 0.575 deep at the center of the hole. That's between 0.725" and 0.775"

The depth between the lip of the cover and the top where the pin would sit is also 0.200", so the pin would just touch the top of the inside of the cover owing a small amount for gasket thickness.

Several companies manufacture 3/8" hardened dowel pins of various lengths. If I had a lathe I could make one.

I'll see what's available.

[17thAirborne]

Dozens of suppliers available from single qty to 100 per pack. Purchased a small pack. I'll post how they work and if anyone runs into this issue I'll send you one of the pack.

[17thAirborne]

I might be overthinking this, but I am finding a few discrepancies that may be problematic...or not. The two RFJP snap rings for the input and output bearings on the main shaft are not as thick as as the original. They are 0.080" thick and the originals are 0.090" Thick. I have re-installed the original snap rings as they appear to be a better fit that the newly made ones.

Also, the snap ring, 7059 that holds the clutch hub and the hi/inter gear on, bent out of round when installing. Perhaps too much pressure with the ring pliers, but I'll have to get another.

Installing and removing those snap rings is not an easy task. I have not found a decent set of pliers. Most are the ones for the rings with the little holes, and the piston rig pliers are not sturdy enough to expand the rings. I don't have enough hands to use screwdrivers, and the dogs are no help...as usual. On hold with transmission...again...for parts.