Deuce 3053A Transmission pops out of 3rd and 5th

Hey everyone,

From what I've been able to search out, it seems that the problem is due to worn synchronizers. I'm a little confused though because this is out of the blue, I haven't had any problems with those gears at all. No grinding during shifts or pop-outs before and now it's happening with two at once. Fourth has always ground occasionally, but never popped out.

I haven't taken anything apart yet because the driveway already has another unrelated problem child taking up needed room. Trying to get some ideas on whether to go for a rebuild (hopefully in-frame) or just get a take out and be done with it. Has anyone had this problem and what did you do? Are the synchros reasonably priced and who can I get them from? Anybody got a good takeout? Anybody need some M923 parts they'd willing to trade for?

Already got a few PMs out, but would appreciate any help I can get. Thanks, Rick

Maybe its time for an inspection and overhaul...

Synchronizers usually are the first suspects. But if for example the rear bearing (6308 ) on the output shaft already got some axial play, then things like you describe can also happen.
1st, try to grab the output flange and check for play. There should be none.
2nd, remove the top and take a closer look inside. Most of the critical wear areas can be seen- and evaluated without even draining the oil. As always, a few close-up pics would be helpful for further advice.

Most internals are still available and not terribly expensive. Just need to shop around, a bit.

PM sent

We have military rebuilt option to offer

https://www.easternsurplus.net/PartDetails/3568/M35A2-5-Speed-Transmission

Thanks for the responses. I will be checking for that axial play today. I checked with my buddy at NAPA today and he's got a guy. He worked for Spicer or Eaton and still has the contacts, etc. He said to pull the serial # off of the tag and call back to check for pricing. If it pans out, I'll post up prices and such. As long as the parts aren't too expensive, and if I decide to rebuild, I'll be replacing as many of the wear parts as I can. Might as well do it once and be done.

One of the threads I found told the story of just putting some oil in it and all was well, but when I checked yesterday, it wasn't low by much. I topped it off and tested, but still had the same problem. So much for the easy fix.

As soon as I can clear the driveway, I'll pull the top and start looking and taking pictures. Rick

Just checked for play at the output shaft and there was none, neither axial or radial. Thanks.

Did get the numbers off of the tag, so I'll be contacting NAPA soon. Want to check the TM first to see what stuff there is and its proper name.

Regardless of its being 51 years old, the truck is in really good shape. All I had to do initially was some body work to cure some rust issues. It has an overhaul tag from 1-8-90 on the door sill. So it has been gone through. I think it may have been used in Desert Storm as there was an inverted V under one of the many layers of paint on the doors. The point being that there probably aren't that many miles on the transmission.

gringeltaube said:

Maybe its time for an inspection and overhaul...

Synchronizers usually are the first suspects. But if for example the rear bearing (6308 ) on the output shaft already got some axial play, then things like you describe can also happen.
1st, try to grab the output flange and check for play. There should be none.
2nd, remove the top and take a closer look inside. Most of the critical wear areas can be seen- and evaluated without even draining the oil. As always, a few close-up pics would be helpful for further advice.

Most internals are still available and not terribly expensive. Just need to shop around, a bit.

Click to expand...

Just to put a bug in your ear...if you take the transmission shafts out and press gears off, that would be the time to consider the overdrive modification from Waterloo specialties. The owner, m35-tom also has transmission parts, bearings etc. for the Spicer.

Along the same lines...I'm sure it's in a TM, but what does one look for in synchro wear? Thanks

I'm sure there are other pictures posted but here is one: https://www.steelsoldiers.com/showt...ing-out-of-5th&p=238242&viewfull=1#post238242

How about inspection related to the function of the braking action/ease of shifting? I have three trucks and my best trans (in the '70) is mediocre about ease of shifting, but I have no other trucks around to reference for "feel". I generally double clutch it because I don't like to force things. The NV4500 in my Cummins Dodge is the same way. I hate stick shifts that don't like to shift... :-/

Planning to go thru my recently acquired trans which appears to be in good shape based on pulling the top cover and wobbling 2nd on the main shaft.

Thank you, sir, for all your many contributions here!

dikwks said:

It has an overhaul tagfrom 1-8-90 on the door sill. So it has been gone through. I think it may have been used in Desert Storm as there was an inverted V under one of the many layers of paint on the doors. The point being that there probably aren't that many miles on the transmission.

Click to expand...

View attachment 733569

I have some bad news. Your truck may well have been serviced or overhauled or washed at some point but that tag above only means it had seatbelts added to it.

See the 200-35 number on the tag?

https://www.steelsoldiers.com/showthread.php?13542-M35A2-seatbelt-MWO-info

A truck overhaul may have had no tag at all or one like this:

I run a machine and welding shop and am pretty handy. I replaced all the bearings, main and 2nd in mine (thanks in part to your bearing list). Should have investigated wear more while I was in there. Do it again...

@clinto

Well, crap! Another cherished assumption shot down by facts and logic! But still, ain't she purty?


I believe that a lady friend of yours got me that cargo cover a couple of years ago. A big thanks to Dawn Crook for a smokin' hot deal! It may be a little mis-matched, but it helps it fit right in around here.



As soon as I get this fine piece of Japanese automotive technology out of my drive way, the deuce is coming in for service.

Got it in the driveway and pulled the top off. Found some wear on the forks, but doesn't seem awful.


Checked the synchronizers and found that they look pretty worn


The gears themselves look ok in that they don't seem excessively worn, although they do have some rust. Maybe there was some water in there at some point.

Pulled the drain plug and got this



Fished out the rest of it with a magnet, at least I seem to have gotten all of the big chunks. Looking down inside the transmission, I can't see where it came from. Anybody know what it is?

Ah... you found the problem(!) - I mean the cause of it... That belongs to the 5th gear sleeve. Without the collar, the gear can move backwards enough to slip out of engagement.
I have found that collar split off of the sleeve, but always remaining in place; never broken in pieces like that!

Prepare to pull the mainshaft assembly and let us know if/when you need help.




Edit to add, after studying your pics:
1) The synchros don't look that bad to me. They may work for another 50.000 miles...
2) A new shift fork measures 3/8". Only replace if you find 0.33" or less.
3) That much rust on the gears is nothing! ... Almost brand new!

G: Thanks for the fork info, just checked and they're all running between .368 and .373. I've gotten the shaft out and pulled it down to where I need the press.

The input shaft looks a little worn but the synchro dogs are not terribly misshapen. Each shot is 120deg from the other.


Some better pictures of the 4-5 synchro from both sides (120deg separation)



More to come shortly.

Got the snap ring for 5th off and got some pictures of the ring and thrust washer as well as front and rear pictures of the gear. The thrust surfaces look rough.


I don't have access to a press yet, maybe Monday. Got two pictures of the area where the broken thrust washer was, looks real rough. Is that cause for a main shaft replacement?

Checked your pics...

• Input shaft is OK.
• 4th-5th sync has seen better days; specially its 5th gear end shows quite some wear on the drive side flanks of the dogs.
• 5th gear has seen some heat but may be reusable, after all. Rear thrust surface sure needs to be polished.
• 3rd gear: its center/front face is way overheated from friction and is probably too soft now! Replace if possible.
• The MS itself may be reusable, after some TLC.

Let's see some more pics after complete disassembly.

Follow Cattlerepairman's advice: contact our member m-35tom; most likely he has all the parts you need.

How about diagnosis of the braking cone areas?

DavidWymore said:

How about diagnosis of the braking cone areas?

Click to expand...

Usually that is not an issue; the dogs from the synchros wear out faster.

There is a way to check for wear - on the work bench, at least: put the synchro in Neutral and stick the gear inside; then measure the distance left between tips of dogs, of both parts....

Another good test: slightly press the gear down - by hand and then lift it straight up. The synchro should remain stuck to the gear and not fall off from its own weight...

I got the mainshaft taken down today. These are some seriously ugly pictures.

As for 2nd and 3rd gears, the faces of bores don't look awful, but given the look of those sections of the mainshaft, those bores are trashed.

Here's the critter that started this all put back together, sorta.

All comments and expressions of sympathy are welcome.