Newbie needs some transmission repair advice, please

[Eracer46]

Have a 1966 M35A2 (which we bobbed and are restoring). While installing a custom back-up beeper micro-switch on top of the gearbox, I unknowingly removed the nut, moved iit a bit left and right, and rotated (but did not remove) the 6 1/2" long (5 - 3/4" usable length) x 5/16" fine thread shaft (looks like a long bolt -- see photos -- fingers pointing to both ends) located just below and rearward of the bottom of the shift lever. It is on the topmost part of the gearbox. The truck had been shifting fine prior to this dumb move. Once I put her all back together, I could shift into all gears while the truck was stationary, BUT when the truck is moving, it will not shift into or out of the gear that you are in when you lift the clutch. It will roll and drive, but it is locked in that single gear.

Anyone know what I did, and how to fix it? I am guessing that I de-coupled the synchros, or worst, by moving and rotating that shaft. Before I pull the top section of the gearbox, I would like to know what I am really getting into, and if I might need parts, or is it (hopefiully) simply a re-alignment or re-connection job.

Thanks in advance.

Love the Deuce......being built for flood rescue service.....

 

[frank8003]

watching this cause I will learn stuff..............

 

[Eracer46]

watching this cause I will learn stuff..............

Just read TM 9-2520-246-34-1 pages 54 to 105 and it looks like those two "screws" do not attach directly to the forks, or have other features attached to them. They have one spring on each of them, and have a 45-50 ft-lb torque requirement, which I will go and check. Not obvious what the issue is.....once re-torqued, I will try to drive and shift it while underway again. Very unlikely that I torqued that small bolt to that level......

 

[Eracer46]

Just read TM 9-2520-246-34-1 pages 54 to 105 and it looks like those two "screws" do not attach directly to the forks, or have other features attached to them. They have one spring on each of them, and have a 45-50 ft-lb torque requirement, which I will go and check. Not obvious what the issue is.....once re-torqued, I will try to drive and shift it while underway again. Very unlikely that I torqued that small bolt to that level......

FIXED IT! Pulled the center floorboard, and tried to re-torque the troublesome, rearward 5/16' bolt, and found that the nut threads were stripped, and the bolt was maybe at 20 ft-lbs and holding, but far looser than spec. There was enough good thread to double-nut it, and then torqued it up to 45 ft-lbs. Took her for a spin and she sifted perfectly! The TM taught me that (1) the torque spec on these two bolts is CRITICAL, and these two bolts precisely hold in-place the plate which guides the forks that cpontrol shifting. One loose bolt = out-of-alignment = fork and synchros don't work.

Hope this helps someone else.....

 

[frank8003]

FIXED IT! Pulled the center floorboard, and tried to re-torque the troublesome, rearward 5/16' bolt, and found that the nut threads were stripped, and the bolt was maybe at 20 ft-lbs and holding, but far looser than spec. There was enough good thread to double-nut it, and then torqued it up to 45 ft-lbs. Took her for a spin and she sifted perfectly! The TM taught me that (1) the torque spec on these two bolts is CRITICAL, and these two bolts precisely hold in-place the plate which guides the forks that cpontrol shifting. One loose bolt = out-of-alignment = fork and synchros don't work.

Hope this helps someone else.....

You did good and correct
Bolts and nuts at that position are critical
Would your like the fastener particulars?

 

[Eracer46]

You did good and correct
Bolts and nuts at that position are critical
Would your like the fastener particulars?

Yes — I would like to replace that bolt, but if I pull it out, the spring will probably fall off and I will need to pull the top section. But yes — where can I find the bolt spec? Thanks, Frank!

 

[frank8003]

Jackshaft nuts bolts joints 11042016.docx



Have you checked the jack shaft bolts (short drive shaft between tranny and transfer case)? They have a tendency to come loose and make all sorts of strange noise at lower shaft rpm.







take the passenger seat out because it's a heck of a lot easier to work on the jack-shaft from the top than it is from under the truck. If a lot of people have trouble with the jack-shaft bolts coming loose, this could be a reason why....you can't get the proper leverage on the wrenches to tighten them properly from the bottom....you're too limited on space.

It's only 4 bolts and about 10 minutes to take the seat out.



Jackshaft u joints
as far as i have ever found there are only 2 'u' joint numbers for the duece. 332 for the large ones and 330 for the small ones. shop around, napa and some other places have really high prices!!





http://www.steelsoldiers.com/showthread.php?43855-Deuce-Jackshaft





Best to get new nuts if they are lose. I think they call them a stover nut or some thing like that. It's the kind of nut that the top has some dents in it pointing to the inside. They are a one time use type nut. Ny-locs will losen up. And as mat said it easy to get to from the bottom side. Block the wheels, leave both the trans and trafer in N and you can spin the shaft easy. You may want to use a pray bar to hold the shaft in place to tighten the bolt/nuts. If you still need a pic I've got the tunnel open and have some of those nuts if you need a pic of them.



1/2"-20 Yellow Zinc Finish Steel Top Lock Nut USA for Grade 9 Applications




Wholesale: $1.21 / each





Availability:

Shipping: Email websales@fastenal.com for availability

Show Inventory Availability for my local Fastenal store



*This is not a standard fastenal.com product

Fastenal Part No. (SKU): 38084

UNSPSC : 31161716 Manufacturer: Fastenal Approved Vendor

Category: Fasteners > Nuts > Lock Nuts



If somebody more knowledgeable than me interprets this differently I'm all ears, but it looks to me like a standard grade five bolt with an ungraded crimp lock nut.
5306-00-752-1001

7521001 U S ARMY TANK AUTOMOTIVE COMMAND AMSTA-IM-MM 19207
80P1 DIAMOND REO TRUCK CO 56442
913491 SASCO INC CANADIAN DIV 58275
5306007521001 E C A ETABLISSEMENT CENTRAL DES APPROVISIONNEMENTS SCY13


THREAD CLASS 3A
THREAD DIRECTION RIGHT-HAND
THREAD LENGTH 0.803 INCHES MINIMUM AND 0.823 INCHES MAXIMUM
FASTENER LENGTH 1.490 INCHES MINIMUM AND 1.510 INCHES MAXIMUM
NOMINAL THREAD DIAMETER 0.500 INCHES
THREAD QUANTITY PER INCH 20
HARDNESS RATING 24.0 ROCKWELL C MINIMUM AND 34.0 ROCKWELL C MAXIMUM OVERALL
MATERIAL STEEL COMP 3135 OVERALL
MATERIAL DOCUMENT AND CLASSIFICATION SAE ASSN STD SINGLE MATERIAL RESPONSE OVERALL
THREAD SERIES DESIGNATOR UNF



5310-00-062-4954

H55-8CW ALCOA GLOBAL FASTENERS INC. DBA KAYNAR PRODUCTS 15653
H55-8CW ALCOA GLOBAL FASTENERS INC. DBA ALCOA FASTENING SY 75237
MS21045-8 NATIONAL AEROSPACE STANDARDS COMMITTEE AEROSPACE I 80205
MS21045-8 MILITARY STANDARDS PROMULGATED BY MILITARY DEPARTM 96906
F1801-080 MACLEAN-FOGG COMPANY DEL DBA MAC LEAN-ESNA 019L2
F52MXE-820 MACLEAN-FOGG COMPANY DEL DBA MAC LEAN-ESNA 019L2
S862TN5-820 NORTHROP GRUMMAN SYSTEMS CORPORATION 26512
27FH-820 SPS TECHNOLOGIES LLC DBA AEROSPACE DIVISION DIV AE 56878
F1801-080 HARVARD INDUSTRIES INC 72962
YE3184 LAMSON AND SESSIONS CO THE 75497

THREAD CLASS 3B
THREAD DIRECTION RIGHT-HAND
NUT STYLE A12 HEXAGON
THREAD SERIES UNJF
THREAD QUANTITY PER INCH 20
HARDNESS RATING NOT RATED
NOMINAL THREAD SIZE 0.500 INCHES
MATERIAL STEEL OVERALL
SURFACE TREATMENT CADMIUM OVERALL
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION QQ-P-416,TYPE 2,CLASS 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
This is the nut that Alcoa provides. No luck finding pics from a specific supplier of the bolt.

 

[frank8003]

see the picture
Grade ( 9 - nine) nuts.

 

[Eracer46]

Jackshaft nuts bolts joints 11042016.docx



Have you checked the jack shaft bolts (short drive shaft between tranny and transfer case)? They have a tendency to come loose and make all sorts of strange noise at lower shaft rpm.







take the passenger seat out because it's a heck of a lot easier to work on the jack-shaft from the top than it is from under the truck. If a lot of people have trouble with the jack-shaft bolts coming loose, this could be a reason why....you can't get the proper leverage on the wrenches to tighten them properly from the bottom....you're too limited on space.

It's only 4 bolts and about 10 minutes to take the seat out.



Jackshaft u joints
as far as i have ever found there are only 2 'u' joint numbers for the duece. 332 for the large ones and 330 for the small ones. shop around, napa and some other places have really high prices!!





http://www.steelsoldiers.com/showthread.php?43855-Deuce-Jackshaft





Best to get new nuts if they are lose. I think they call them a stover nut or some thing like that. It's the kind of nut that the top has some dents in it pointing to the inside. They are a one time use type nut. Ny-locs will losen up. And as mat said it easy to get to from the bottom side. Block the wheels, leave both the trans and trafer in N and you can spin the shaft easy. You may want to use a pray bar to hold the shaft in place to tighten the bolt/nuts. If you still need a pic I've got the tunnel open and have some of those nuts if you need a pic of them.



1/2"-20 Yellow Zinc Finish Steel Top Lock Nut USA for Grade 9 Applications




Wholesale: $1.21 / each





Availability:

Shipping: Email websales@fastenal.com for availability

Show Inventory Availability for my local Fastenal store



*This is not a standard fastenal.com product

Fastenal Part No. (SKU): 38084

UNSPSC : 31161716 Manufacturer: Fastenal Approved Vendor

Category: Fasteners > Nuts > Lock Nuts



If somebody more knowledgeable than me interprets this differently I'm all ears, but it looks to me like a standard grade five bolt with an ungraded crimp lock nut.
5306-00-752-1001

7521001 U S ARMY TANK AUTOMOTIVE COMMAND AMSTA-IM-MM 19207
80P1 DIAMOND REO TRUCK CO 56442
913491 SASCO INC CANADIAN DIV 58275
5306007521001 E C A ETABLISSEMENT CENTRAL DES APPROVISIONNEMENTS SCY13


THREAD CLASS 3A
THREAD DIRECTION RIGHT-HAND
THREAD LENGTH 0.803 INCHES MINIMUM AND 0.823 INCHES MAXIMUM
FASTENER LENGTH 1.490 INCHES MINIMUM AND 1.510 INCHES MAXIMUM
NOMINAL THREAD DIAMETER 0.500 INCHES
THREAD QUANTITY PER INCH 20
HARDNESS RATING 24.0 ROCKWELL C MINIMUM AND 34.0 ROCKWELL C MAXIMUM OVERALL
MATERIAL STEEL COMP 3135 OVERALL
MATERIAL DOCUMENT AND CLASSIFICATION SAE ASSN STD SINGLE MATERIAL RESPONSE OVERALL
THREAD SERIES DESIGNATOR UNF



5310-00-062-4954

H55-8CW ALCOA GLOBAL FASTENERS INC. DBA KAYNAR PRODUCTS 15653
H55-8CW ALCOA GLOBAL FASTENERS INC. DBA ALCOA FASTENING SY 75237
MS21045-8 NATIONAL AEROSPACE STANDARDS COMMITTEE AEROSPACE I 80205
MS21045-8 MILITARY STANDARDS PROMULGATED BY MILITARY DEPARTM 96906
F1801-080 MACLEAN-FOGG COMPANY DEL DBA MAC LEAN-ESNA 019L2
F52MXE-820 MACLEAN-FOGG COMPANY DEL DBA MAC LEAN-ESNA 019L2
S862TN5-820 NORTHROP GRUMMAN SYSTEMS CORPORATION 26512
27FH-820 SPS TECHNOLOGIES LLC DBA AEROSPACE DIVISION DIV AE 56878
F1801-080 HARVARD INDUSTRIES INC 72962
YE3184 LAMSON AND SESSIONS CO THE 75497

THREAD CLASS 3B
THREAD DIRECTION RIGHT-HAND
NUT STYLE A12 HEXAGON
THREAD SERIES UNJF
THREAD QUANTITY PER INCH 20
HARDNESS RATING NOT RATED
NOMINAL THREAD SIZE 0.500 INCHES
MATERIAL STEEL OVERALL
SURFACE TREATMENT CADMIUM OVERALL
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION QQ-P-416,TYPE 2,CLASS 3 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
This is the nut that Alcoa provides. No luck finding pics from a specific supplier of the bolt.

Thankfully, Jason -- Beltfed -- also gave me that great advice to check those jackshaft bolts, which I did a few weeks ago. All were tight and to spec. I checked them from above, but did not have to change any out.

I will buy new bolts for the issue that started this thread, and try to replace the bad actor without losing the spring position. Worst case is I have to pull the top section. Another new adventure!

Thaks for your advice, Frank. Appreciate it very much.

-Brian -- Eracer46

 

[gringeltaube]

Yes — I would like to replace that bolt, but if I pull it out, the spring will probably fall off and I will need to pull the top section. ....

It's fixed, so leave it alone! These two bolts serve as a pair of rails for the shift plate to slide left-right, besides each one holding a spring and a couple of spacer washers. Loose- or tightened- makes absolutely no difference in its function and to how the transmission will shift.
From factory, bolts are sealed against the housing by tiny copper rings/washers that go under the bolt head and nut, respectively. The only thing that can happen if too loose is a little oil creeping out.

Replacing that bolt with the cover installed is possible but very risky - like playing with fire...(!)

Below is how it looks inside, with the shift plate in place and only the 1st-reverse shift rail & fork installed (missing set screws and safety wire when pic was taken).

 

[Eracer46]

It's fixed, so leave it alone! These two bolts serve as a pair of rails for the shift plate to slide left-right, besides each one holding a spring and a couple of spacer washers. Loose or tightened makes absolutely no difference in its function and to how the transmission will shift.
From factory, bolts are sealed against the housing by tiny copper rings/washers that go under the bolt head and nut, respectively. The only thing that can happen if too loose is a little oil creeping out.

Replacing that bolt with the cover installed is possible but very risky - like playing with fire...(!)

Below is how it looks inside, with the shift plate in place and only the 1st-reverse shift rail & fork installed (missing set screws and safety wire when pic was taken).

View attachment 805964

Thank you, Gringletaub. Sadly, the test drive went flawlessly, but later yesterday afternoon, I took my wife for a ride, and after one shift, the same no-shift condition occurred. This time, double-clutching helped to shift one more time from 2nd to 3rd, but then it wouldn’t shift again unless stopped. What do you recommend? Try to re-build the top, or buy a used but intact upper? Really appreciate your advice.

 

[gringeltaube]

Time to pull the cover and take a look inside. Shift plate may be worn or cracked/broken. But there are other possible causes, too.
Clean, inspect and shoot some closeups of all suspected parts. It is much easier to help you when we can see some pics.

 

[Eracer46]

Time to pull the cover and take a look inside. Shift plate may be worn or cracked/broken. But there are other possible causes, too.
Clean, inspect and shoot some closeups of all suspected parts. It is much easier to help you when we can see some pics.

Will do. We won’t be back there for ten days but will start a new thread at that time. Newbie is the code word....

 

[Eracer46]

Will do. We won’t be back there for ten days but will start a new thread at that time. Newbie is the code word....

Just removed the top section of the transmission (for the first time ever.....!) Attached are some photos. Only thing my novice eye spotted are some apparently heat-affected areas -- rainbow-ish hues. I am a bit fearful of removing too many more pieces and the safety wires etc. That is beyond my novice skills. Unless there are clear steps written somewhere..... Anyone (gringletaube, please) see anyting unusual? As a reminderr -- The M35A2 won't shift when the vehicle is moving, only when fully stopped. Thanks.

 

[Eracer46]

A friend asked what weight transmission oil I am using and it is 80-90 weight. I looked up the spec in TM 9-2520-246-34-1 and it specifies Lubricating oil, ICE, OE/HDO 10, MIL-L-2104, which in its variants runs from 10W to 30W. Could it be that the heavier oil I am using is causing this inability-to-shift-on-the-move problem? What weight oil do you run in your 5-speed gearbox? Thanks.

 

[m715mike]

Hi Brian. I run gear oil in mine. My transmission does not like lighter weight oil. I would recommend staying with the gear oil.

-Michael

 

[Mullaney]

A friend asked what weight transmission oil I am using and it is 80-90 weight. I looked up the spec in TM 9-2520-246-34-1 and it specifies Lubricating oil, ICE, OE/HDO 10, MIL-L-2104, which in its variants runs from 10W to 30W. Could it be that the heavier oil I am using is causing this inability-to-shift-on-the-move problem? What weight oil do you run in your 5-speed gearbox? Thanks.

Eracer46, I agree with @m715mike about the gear oil. The 80w90 has a "sulpher smell" especially when it is warm. Company that I worked for in the 1980's had hundreds of Deuces and almost two hundred 5 Tons. All with gearboxes and clutches - before the Allison automatic was the thing to have. Every last one of them ran 80w90 in the gearbox, transfercase, and axles. I can say that with some authority 'cause when I started there - that was my job. Grease and Fluids. Oh my what fun! (really - it was at the time!)

Just for the heck of it, have you considered draining the transmission? Plug down there on the bottom side that generally opens with a half inch drive ratchet. Catch the oil in a clean pan and inspect it. Look for slivers of metal in it. Get a sheet of clean white paper, dip your finger in the oil and wipe it across the paper. Metal shavings will reflect in the sunlight.

There has to be a logical reason why you can't shift in motion.

If the synchronizers or any bearings are failed or failing, you should see metal in that gear oil. When you get ready to refill the transmission, several quart bottles will be required and a piece of rubber hose that fits the pointed spout on the bottle will be your friend. Larger diameter hose is good. that stuff is thick and hard to move... Just make sure it is stuck well onto the bottle and that the end will fit in the fill hole up on the side of the transmission. Heck, if what you have is pristine and money is tight - strain it through a T-Shirt and put it back in there!

Report back and let us know what you find?

 

[gringeltaube]

Just removed the top section of the transmission (for the first time ever.....!) Attached are some photos. Only thing my novice eye spotted are some apparently heat-affected areas -- rainbow-ish hues. I am a bit fearful of removing too many more pieces and the safety wires etc. That is beyond my novice skills. Unless there are clear steps written somewhere..... Anyone (gringletaube, please) see anyting unusual? As a reminderr -- The M35A2 won't shift when the vehicle is moving, only when fully stopped. Thanks.

Except for the cover gasket, everything else you are showing there looks very clean and normal to me. (The tips on the forks are heat-treated; that's why they are blue.)
Your hard-shifting issue may be caused by something further down in that box. Still, we want to check the condition of the shift plate ("AA" in the diagram below), before proceeding to other areas.
Does your plate look like this one (or even nicer, without any rust spots) ?:
Are both tabs still there? It can be checked without further disassembling. Also look for any signs of wear, for example where the shift shaft engages the forks. Bad parts look like these:


Top cover assembly, exploded view:



Clear steps for taking apart and re-assembling the cover are explained in this book, pages 2-36 to 2-41.

 

[Eracer46]

Eracer46, I agree with @m715mike about the gear oil. The 80w90 has a "sulpher smell" especially when it is warm. Company that I worked for in the 1980's had hundreds of Deuces and almost two hundred 5 Tons. All with gearboxes and clutches - before the Allison automatic was the thing to have. Every last one of them ran 80w90 in the gearbox, transfercase, and axles. I can say that with some authority 'cause when I started there - that was my job. Grease and Fluids. Oh my what fun! (really - it was at the time!)

Just for the heck of it, have you considered draining the transmission? Plug down there on the bottom side that generally opens with a half inch drive ratchet. Catch the oil in a clean pan and inspect it. Look for slivers of metal in it. Get a sheet of clean white paper, dip your finger in the oil and wipe it across the paper. Metal shavings will reflect in the sunlight.

There has to be a logical reason why you can't shift in motion.

If the synchronizers or any bearings are failed or failing, you should see metal in that gear oil. When you get ready to refill the transmission, several quart bottles will be required and a piece of rubber hose that fits the pointed spout on the bottle will be your friend. Larger diameter hose is good. that stuff is thick and hard to move... Just make sure it is stuck well onto the bottle and that the end will fit in the fill hole up on the side of the transmission. Heck, if what you have is pristine and money is tight - strain it through a T-Shirt and put it back in there!

Report back and let us know what you find?

Thank you, gringeltaube, Mike 715 and Mullaney! I plan to drain the 80-90 weight today, inspect the fluid and the top plate, as you have suggested, and see what we find. The internals of the gearbox actually look very pristine, as a friend said -- "almost as clean as an automatic transmission." But we still could have metal slivers -- that is today's mission. Having read most of the related threads, it is hard to tell if this is a fluid issue or a mechanical failure issue -- I suppose it could be either. One bit of evidence -- I drove to and from a parade -- maybe 60 miles -- using this gear oil a year ago, and it worked well, both slow speeds and max highway speeds too (about 52 mph for me). So this is a new issue. Will report back later today. THANK YOU ALL! I am a newbie, and stuck without your guidance.......

 

[Eracer46]

Thank you, gringeltaube, Mike 715 and Mullaney! I plan to drain the 80-90 weight today, inspect the fluid and the top plate, as you have suggested, and see what we find. The internals of the gearbox actually look very pristine, as a friend said -- "almost as clean as an automatic transmission." But we still could have metal slivers -- that is today's mission. Having read most of the related threads, it is hard to tell if this is a fluid issue or a mechanical failure issue -- I suppose it could be either. One bit of evidence -- I drove to and from a parade -- maybe 60 miles -- using this gear oil a year ago, and it worked well, both slow speeds and max highway speeds too (about 52 mph for me). So this is a new issue. Will report back later today. THANK YOU ALL! I am a newbie, and stuck without your guidance.......

So....I drained the 80-90 weight that was in the transmission and put it through a coffee filter and fine screen. Then swept it with a super magnet, and pulled sludge from the bottom of the case through the drain hole with my finger. Looked at all residue in the sun, on a white background. See photos. Bottom line: zero evidence of any shavings or visible-size metal at all, other than what I would call gray dust or pumice. Just for fun (and to make 50% of you happy), I filled the case with ND SAE 30 weight, put the cover back on and just now drove it. Whie I still could not get it INTO gear while in motion, I now could get it SMOOTHLY OUT of gear every time while in motion. This is a change. No idea why. I tried shifting OUT of gear without the clutch (on the advice of a friend), and it would not go out of gear without the clutch whether moving or idle. I tried all 5+R gears, and they all go in while stopped easily, and they are engaged perfectly, and try to move the Deuce when I lift the clutch -- all normal. The last thing I did was try to put it back INTO 2nd gear as I coasted into my garage in Neutral, and at about 2 mph, with the clutch in, it ground a little bit, and went into second gear. So, the Deuce doesn't have to be EXACTLY stopped, but it did grind (the synchros?) as I pushed it with low-medium effort into second that last time.

I took photos of the top plate and it looks normal without visible wear, and no cracks or damage.

I have new 80-90, but for now, will leave the 30 in there.....

Help! Not sure what else to try. Thanks to everyone who is helping me through this....