1984 DN 4-3 popping out of second

[Heyblue]

Running close to red line then letting off throttle on a slight down hill. The rapid de acceleration causes the transmission to occasional pop out of 2nd. I have unit out of car because of trouble with the OD section. Will be replacing it with a rebuilt unit. Is my second gear problem a linkage or gear problem? Don't want to tear down the unit but will if need be. I do not have any "special" tools. Has others done the tear down with standard tools and makeshift special items?

 

[forrest]

Running close to red line then letting off throttle on a slight down hill. The rapid de acceleration causes the transmission to occasional pop out of 2nd. I have unit out of car because of trouble with the OD section. Will be replacing it with a rebuilt unit. Is my second gear problem a linkage or gear problem? Don't want to tear down the unit but will if need be. I do not have any "special" tools. Has others done the tear down with standard tools and makeshift special items?

before diving into the transmission with both feet let's take a step back a bit, when shifted into gear does it feel like it is fully engaging into gear. are the shift forks worn? not allowing the slide collar to fully slide over the teeth. is their play in the linkages. rule out all easy and much cheaper things first. who knows maybe a combination of sloppy forks and loose linkages could add up to popping out of gear.

with the side cover off you can give all a good inspection and look at the syncro splines because it also sounds like your NOT having problems of grinding gears when power shifting but if locking collar and it's matching splines were beat up I hazard it could cause a pop out, so I would give a good look at and other things first before pulling T-10 apart.

I have had a few T-10s apart And I have found that they can be done at home (though I have never done at home) most of the tools needed are in a well tooled home garage, good sockets,large Hammer,a tub of Transmission assembly lube (it's a red Vaseline like lube) and a set of large snap ring pliers (including the type for large rings with pointed ends that need to be spread) if need be a trip to Home Depot/Lowe's for some pipe for driving things back together, the one tool that would make the job harder is not having a 10 or so ton press for pushing collars off if they were stuck and pressing back on instead of beating on with Hammer.

I would also recommend taking things apart in sets and keeping them in sets like the input shaft and needle bearings, 3-4 syncro with it's rings everything laid out in order they came out how they came out.

Now a little warning from a mistake made by a trans shop a friend took his car too, they mistakenly replaced only the first set of syncro's they came to (the ones behind the input shaft) and those are the 3-4 (Direct gear) his goal like yours was the 1-2 Syncro, so since you have it apart I would recommend replacing both unless you feel the 3-4 gear syncro is truly good.

 

[Heyblue]

When I was driving it "felt OK" when shifting but since unit is out of car, it is now hard to really scrutinize it.
I kind of have a 10 ton press, i.e. a 12 ton log spliter, I can pull off the splitting head and just use the ram and some clever home made fixtures maybe.
Started opening things up and the first real issue is removing the front bearing. Have the two clip rings removed and the shaft and bearing can be slide out of cast about 1/4 inch. The shop manual shows a special tool the seems to attach to the grove on the bearing plus the long bolts to pull it off the input shaft. Not sure how to solve this yet. Maybe after I remove the rear plate and just rap the shaft from the front?
With the side cover off, the shifter forks do not seem excessively worn. With the forks removed I can slip the unit into each gear (1-2) and (3-4). They seem to snap into position. When in gear not just 2nd but each gear, if I grab input and output shaft and try to rotate them in opposite directions I notice that there is fair amount of play on the syncro? as I apply the twisting action on the shafts. They kind of cock sideways a little. Having nothing to compare to I do not know if this is normal, but guesting it is not. All the gears look very good, no obvious nicks/chips. The "syncros" seem to be an assembly made up of half dozen parts. A rebuild kit on Ecklers states that it includes syncro rings. Another kit on ebay talks about having syncro springs. If I look for just "syncros" for this transmission I do not get anything. Does the rebuild kits supply the wear parts that would fix syncrows?
Kind of feel that queasy feeling like when I was 10 and took my first watch apart.

 

[forrest]

When I was driving it "felt OK" when shifting but since unit is out of car, it is now hard to really scrutinize it.
I kind of have a 10 ton press, i.e. a 12 ton log spliter, I can pull off the splitting head and just use the ram and some clever home made fixtures maybe.
Started opening things up and the first real issue is removing the front bearing. Have the two clip rings removed and the shaft and bearing can be slide out of cast about 1/4 inch. The shop manual shows a special tool the seems to attach to the grove on the bearing plus the long bolts to pull it off the input shaft. Not sure how to solve this yet. Maybe after I remove the rear plate and just rap the shaft from the front?
With the side cover off, the shifter forks do not seem excessively worn. With the forks removed I can slip the unit into each gear (1-2) and (3-4). They seem to snap into position. When in gear not just 2nd but each gear, if I grab input and output shaft and try to rotate them in opposite directions I notice that there is fair amount of play on the syncro? as I apply the twisting action on the shafts. They kind of cock sideways a little. Having nothing to compare to I do not know if this is normal, but guesting it is not. All the gears look very good, no obvious nicks/chips. The "syncros" seem to be an assembly made up of half dozen parts. A rebuild kit on Ecklers states that it includes syncro rings. Another kit on ebay talks about having syncro springs. If I look for just "syncros" for this transmission I do not get anything. Does the rebuild kits supply the wear parts that would fix syncrows?
Kind of feel that queasy feeling like when I was 10 and took my first watch apart.

Yeah I forgot about that puller but it's not a huge one it should be available at a good parts store or rental shop, what I had used in a pinch when the shop correct puller went MIA was a standard 2 piece puller for smaller bearings and as long it's not to stuck, one of the Key factors is finding a puller that has a flat side edge the can grab the groove that the snap ring sits in most are kind of offset. I don't usually recommend Harbor Freight but here is a link to show a Example
Search results for: 'puller'
14 Piece Gear Puller Set

once you have that bearing off the input shaft the trans comes apart fairly quickly, but I will warn that the trans. requires a little finesse to slide together. Just take lots of pictures as it comes apart and don't loose any Needle bearings.

 

[Heyblue]

Well, paid a shop to pull the input bearing, he said he would press the new one in for free when I am ready. Pulled everything out the back and disassembled the front section. Purchased the kit from harbor tools and pulled rear bearing. Will order rebuild kit with syncro rings Monday when I can talk to supplier to make sure I get the right one. One of the kits talks about a new input nut, but my transmission does on seem to have such a part. Little confused about that. Purchased two sliders (not sure what right name is but they are the things that the shift forks push) They both had wear. Interesting that the 3/4 unit had more wear on the side of forth, expected the 1/2 would have had more. Syncros not that worn, but putting in 4 new ones.