TR2/3/3A Rebuilding a tr3 transmission and second gear,

[sp53]

Sorry John I was not very clear about the question of the tapper. I am not sure I knew exactly how to ask the question because I had not evaluated all the information or saw where all the surfaces met, yet. I see now the area in question is the areas in the center of the big constant mesh gear which gets hidden behind the thrust-washer; it all gets hide when the trust-washer is installed. I did not realize the thrust washer does not rub the entire end of the shaft. The washer has those oil passed ways

I put the large thrust washer onto the case over its hole with some grease to hold it in place. The needle bearings and end caps went back inside the lay shaft with some grease and everything went well.

Next after reading some, I decided to use a ¾ inch dummy rod the exact length of the shaft to hold the needle bearings in place. I set the cluster gears in the bottom of the case. Then I thought I need to get the end float measurement, so I cut another ¾ wood rod; this time I cut the wood rod bigger probably about a foot longer, so the rod would stick out both ends of the transmission case as I push the shorter dummy rod out.

This way the lay-shaft would be sitting were it goes, and I have both hands free to measure the end float. I pick through the washers I had and dropped the one I liked best straight down as I wiggled the rod from the bellhousing end and dropped the thrust-washer in place right when rod passed through giving me about ¼ inch of room to fit the thrust-washer.

I could get a 0.08 feller gauge between the thrust-washer and the shaft, but could not get the 0.008 installed at the distance piece on the shaft. I pulled the feller gauge out the back and wiggle the shaft and the end float looks and sounds about right. The shaft spins nice. I am good, I think.

Now I will push the longer rod out and place the short rod in and drop the cluster set down to the bottom of the case, so I can get the main shaft going. Then mesh the main and the lay shaft when center bearing goes into its hole.

Roy, thanks for the articles. Second gear has always been a problem for me and I am going to replace the balls and springs.

steve

 

[CJD]

So far it looks good!

 

[TR-3rg]

The picture of the cluster gear reminded me of something. Check the straight cut gear teeth on the cluster, 1st and reverse for cracks. I broke one off about 10 miles after I rebuilt it. Fortunately, I had a magnetic drain plug so it did not wipe out the gearbox. Then a tooth is missing, 1st and reverse go click, click, click...

Roy

 

[sp53]

I wanted to replace all the bearings, but the bearing inside the input shaft does not look friendly to replace. Overall the bearing looks fine to me, and I am not sure if this is a common bearing to replace or not. The early gear box had a bronze bushing and these are those gaged needle bearings, probably newer style and an improvement, I hope. I am sure there is some kind of inverted leg small bearing puller out there somewhere. Any thoughts on replacing input shaft bearing?

I decided which main shaft to use and I need to get the new bearings pressed on. When I removed the bearings, I punched them out of the aluminum casing with a drift and hammer, and felt every whack of the hammer hitting waiting for something to break. Taking the bearing off main shaft with a hammer sounds wrong, so I guess I will pay. I think I know a place that still has a machine shop that will press bearing. Then I can get a better idea of how second gear is set up with the large brass bushing and top hat brass bushing.

I slide the brass bushings onto the main shaft with their 2 thrust- washers to get a Mach up to measure the end float of the main shaft for the gears. The float I guess is 0.003 to 0.009. Boy that is not very much in my mind and difficult to get an accurate reading so small. I did not put the circlip on the main shaft to enclose the bushings tight. I could see that the circlip would hold everything in place and perhaps give some wiggle room of 0.005; it was tight. The circlip should go on I suppose to make sure, and I will do it, but again not sure about this area on the main shaft float, so I did not want to fight the circlip for now.

After I get the bearing pressed on, I can start looking at second gear better. I believe John modified one of the large brass bushing for mechanical reasons. Many of the top hat bushings I have seen are broken for some reason, so yes something in that area is questionable for something.

Back in the seventies, I had a tr3 transmission rebuilt at a large local shop and it did not go well. Problems with the top hat washer and second gear where the 2 main problems. I started taking transmissions apart myself after that and learning how to fix them.



Thanks Roy I will look close. I notice a lot of chipping and grinding on the reverse gear on the tr3 transmissions. The first tr3 I bought back in 1970 would not go into revere. Later, I figured out the bolt was broke on the fork inside the bellhousing. However, there many years I fought going into revere before I fixed it. I actually got good at gentle forcing the car into revere.



steve

 

[CJD]

I would likely keep the needle pilot bearing. It only works when the clutch is pressed, so should last very long, unless it gets dirty. If you have to remove it, the same old trick of packing the entire hole with grease and then tapping the input shaft into the grease should work. That hydraulically forces the bearing out of the hole.

 

[sp53]

Thanks John I really appreciate the opinion. The guy at the machine shop said the same thing you did. I had known the bearing only works in neutral, but forgot. He also look the bearing over and felt it was fine. Good therapy.

Anyways I did not give the machinist the rear tail shaft bearing to press onto end of the main shaft. I only gave him the center and front bearing. I did not buy a rear tail shaft bearing because the one tail shaft bearing spun so well in my hand that I bached. They are not that much, and i probably should What are your general thoughts on the tail shaft bearing? It does not seem to me that it has weight on it, but I do not want to be stupid either and not buy one.

I did take an old tail shaft bearing out, I knocked the bearing out with a block of wood and a hammer and the seal and bearing both came out easily. Hopefully, if I do replace the bearing, I will be able to knock a new bearing back inside the tail shaft rear edge easily and slide the tail shaft over the long end of main shaft and pound the ----bearing center hole---- back onto the transmission main shaft splines. It looks to me that the bearing actually wedges onto the main shaft splines some, but again the shaft rounds out also right there. It might go easy, but came off tough. I cannot see another way



steve

 

[TR Tom]

Been following along on this very informative thread since I’m also experiencing same things as the OP.

Don’t want to hijack, but would like to ask John to elaborate on the last sentence of post #16. You say problem may be gear not fully engaging, which makes perfect sense. Finally got a chance to pull the cover on mine and it appears gear could move a little more forward towards the engaged position, but not sure how to tell when it’s fully in. Of course if that’s the problem I then need to figure out which part is wrong, as there doesn’t appear to be any adjustments possible. Like a lot of these old boxes, mine is a mismash of parts.

Thanks for any help,
Tom

 

[CJD]

If the main shaft bearing inspects well...i.e. no pitting, scratches, ball dents on the races, and cage in good shape, then I would have no problem using it. Now days these cars won't likely see 100k+ miles, like they once would, so the bearings should last many years, so long as they don't corrode. On the other thread, Popeye mentioned not turning the tranny when it sat for years. The oil only sits in the bottom of the case, so if the gearbox sits for years, everything above the oil line can corrode, while what's below the line is protected. The main bearing is less than half and half in the oil. (good to spin the shafts every few months while a tranny sits out of the car).

Removing the main bearing requires a bearing splitter...one of those tools that guillotines between the bearing and shaft shoulder. In practice, even using this tool puts a lot of load on the balls. If you have not removed the bearing and it inspects good, then no problem reusing it. If you have removed the bearing, then the balls could brinell the races in the removal, so I would be more prone to replace a bearing that has been removed...unless done very carefully.

Installing the main bearing is a matter of using a long pipe around the tail of the shaft, so you can press against the inner race. That way the balls are never involved in the press.

The tailshaft bearing is the same...if it inspects good and you did not have to bang on the inner race in removing it, then it should be good to reuse.

Tom...I am still trying to figure out why so many people have trouble with these boxes in 2nd gear?!? In American boxes the sliders are machined with slight cups. so the dog teeth on the gear tend to stay inside the slider once they engage...more load holds the teeth even tighter. They tend to have stronger springs and inserts in the hubs, too, which likely help. American trannies do not use any detents in the shifter assemblies to hold the tranny in gear.

The Triumph boxes have straight teeth in the sliders, and rather flimsy insert springs in the hubs. Nothing there to hold the slider in gear! They seem to depend on the ball detents in the shifter assembly to hold them in gear. For now, I can only recommend you inspect the shifter balls and springs, along with the detent in the shifter shaft for wear or weak springs. I think a lot of guys, like Steve, have already done that...so my next question is if the shifter is allowing the slider to fully engage?

 

[sp53]

The machine shop should have the bearing pressed on today. I could not see any problems with the bearing inside races because the outer shells hide the balls. My original bearings made some rocks in a jar noise when spin on the shaft by hand and the new Korean bearing were very quiet, so I choose to have them put on the main shaft.

On the car I drive that falls out of second now , I put that transmission together by the book, but I did not replace the springs and balls in the sliders.

When I tried to fix the falling out of gear by manipulating the shifting tower in that transmission, all I did was tighten up the de-dent ball on the second gear shifting rod. The shifting became stiffer in and out of second and I thought the tightening up of the ball had fix the falling out, but no joy the trans fell out of second anyway mostly going downhill like gravity had something to do with the shifter falling out of second. To me it sounds like new de-dent balls and springs (everywhere) might keep the shifter in gear, but I do not know. Part of me thinks there should more than balls and springs holding the gears in place.

The article that Roy posted stated they were stuck on what to do about second gear also because they could not see anything wrong. They decided to replace the balls and springs, everywhere and that seems to work!

Steve

 

[CJD]

In that large pile of Triumph parts I obtained 10 years ago from an estate sale, I got a ton of gears and gearbox parts. Most were trash. Anyway, there were a couple sliders that were machined with a cup in the splines to hold 2nd gear...this in contrast to the usual straight machining of the splines. I didn't pay them much mind, as that is how all american gears are machined. It seems someone machined aftermarket sliders to help hold second gear?!? They were not marked with any manufacturing info, though.

 

[CJD]

I took the TR2 for a drive today. I don't know if it will help, but the shifter throw into second gear from neutral is 2-1/4", measured at the top of the shift lever. My tranny has no tendency to pop out of second. When in second the shifter feels like it hits a wall, very solid at the second gear stop, and no tendency to move back from this stop. If the shifter is not fully engaging second, I would suspect it to feel more spongie at the second gear stop, because the lockout balls are holding the shifter back a bit.

 

[sp53]

Thanks for driving out and getting a feel for a transmission that works John. I mached up the main shaft with all the gears, bushings and the 2 thrust washers, so I could get an idea of what the main shaft would like when all assemble and in second gear. I took a couple pictures to demonstrate how the slide moves over to the dog teeth and grabs the dog teeth of second when going from first to second.

I left the balls and springs out, so I could slide first gear over to second gear without any drag from the ball and springs. The shifting looks straightforward and moves freely. To me it looks like the balls and springs is what you were saying when you referred to locking into second. The transmission looks mechanically easy and simple as it shifts into second.

What I am thinking is my problem with sliding out of second are the detent balls. The article that Roy added goes into depth about this and makes good points

https://vintagetriumphregister.org/maintain/TransRebuild/TRTrans02.pdf

I think the way second falls out of gear going downhill is the physical weight of first gear. The gear must weigh a pound or more and sits on a slider and then onto those sliding balls. When I go downhill, gravity forces the weighty first gear back and if the balls cannot hold the gear it slides on the slider back and removes first gear from the dog teeth on second gear and then the shifter goes into neutral. Any ideas on this theory?

I have one first gear with a groove cut inside the gear all the way around in a circle where the balls could pop into and hold better. I also have a first gear where there is no groove, so for lock into second there would only be the 4th ball that is fixed into the slidder. Also the strength of the springs should make big difference. I bought all new balls and springs from Moss and some of those little shims they sell to stiffen things up and probably balance the float of the slider.

Like John said the new synchro rings are very sharp to the touch on the inside of the brass edge. I can see why you would want to smooth them out; they just feel to sharp.
steve

 

[sp53]

Hi Tom these are pictures from an earlier tr3 and might not be the same as a tr4 exactly. I am no expert on Transmissions, but it does seem to me when you look at pictures 1594, 1595, and 1596 you can see how much second of second gear is covered in a complete engagement of second gear, basically just the dog teeth of second.

I would say if you removed your cover in second gear your selector should look like picture 1596. If it does, you are all the way into second gear and you problem is in weak detent balls not holding the gear in place.

I am not sure, but I would bet on it.

steve

 

[TR Tom]

Hi Tom these are pictures from an earlier tr3 and might not be the same as a tr4 exactly. I am no expert on Transmissions, but it does seem to me when you look at pictures 1594, 1595, and 1596 you can see how much second of second gear is covered in a complete engagement of second gear, basically just the dog teeth of second.

I would say if you removed your cover in second gear your selector should look like picture 1596. If it does, you are all the way into second gear and you problem is in weak detent balls not holding the gear in place.

I am not sure, but I would bet on it.

steve

Hey Steve
Thanks for the info, and especially the pictures. When you speak of the “weak detent balls” are you talking about the ones in the gears or on the top cover? I have never heard of using a fish scale to measure force required to slide the gears, only heard of doing that with the top cover. Will try to rig up a way to do that like in the very useful link you provided.
You mentioned thinking 2nd slipped out more going down hill, which now sounds familiar. In thinking about it though, when going into 2nd, aren't you pushing the gear towards the front of the car, which would be downhill? Not sure if I’m thinking of this correctly, as transmissions definitely confuse me (although the more I read here, they are starting to make sense).
Never knew how common this problem was. All these years I thought I was the only one. Thanks to all the great members of this community, hopefully I can finally get this one solved.
Tom

 

[sp53]

No, I think you are looking at the sliding going downhill correct. For some reason it made sense to me, that as the car is traveling downhill in second gear that the weight of first gear would hold first gear still and that second gear would pull away. I said it was a theory. I was hoping one of you guys would tell me what you thought. Heck Randall years ago would have told me just how wrong I was, you guys are nicer, maybe.

 

[sp53]

Well I was hoping John would chime in and give his opinion on what could be happening in second gear. If I remember correctly, John modified the top hat or the other brass busing making some distance different on the main shaft. I think he said his shifter goes into third gear further. I am having trouble visualizing the modification.

The fish weight tool deal is also used on setting the drag on the ring and pinion gear shimming. There the fish weight tool feels the drag set past zero tightness on the bearing and race. John your opinion is highly valued. If you are on vacation cancel your plans and come back to the forum where learning in therapy.

Steve

 

[sp53]

I am not sure if the problem is in the ball detents on the shifter or the trans slider. The shifter is probably worn badly. I have driven this car for 40 years and never replaced them and they are a moving part. I forgot to order them from Moss last week but I need to and will replace them.

I am working on a plan to put the gears back in the case. It looks like turn the main shaft upside down and start sliding the gears, bushing, and thrust washers onto the shaft. I notice in some of Johns pictures he slid the circlip down into position on the main shaft with a piece of pipe. Looks like a good idea.

I will get a 5 gallon buck with some clean rags in the bottom and put the long main shaft in the bucket, so the shaft is about vertical and kind of floating side to side. I will then let the center bearing sit just a little into the case then feed the gears onto shaft into the case down the short end of the main shaft.

Because I left the center main bearing loose on the case and vertical, I can tilt the main shaft over to one side enough to get the first batch of gears past the case wall onto the shaft. I will stop putting gears in place at the circlip groove then slide the circlip down into the groove with the pipe to hold those gears tight. Next I will move to input shaft and 3rd and 4th gear with the front main bearing to hook up the whole main shaft as a unit. I hope I have not tried yet.

steve

 

[CJD]

You guys are staying busy!

I always assumed the balls in the slider hub were to ensure the slider remains centered in the neutral position. They could have a slight job holding the slider in gear, but they don't have anything to grab onto to do that. Once again, American trannies have more detents in the slider so the balls have something to grab to also hold in gear.

Steve, the book has a very good description of the order to rebuild the main shaft. You pretty much just follow their order and it will come out right. If you don't, you can get in a jam.

The thing I am interested in finding out is if, once you have the gears all installed, does the shifter fully move the slider into the 2nd gear position? I suspect it may not be fully engaging second. You'll have to temporarily install the cover, shift into second, and then remove the cover to see where the gear actually ends up.

 

[sp53]

For sure I am following the books on assembly. I should have purchased a HF press for around 120.00$ and tried pressing the bearings on and off myself because the bill at our Nappa Machine shop was 146.00$, but that is what it costs today to have stuff done, i guess. Again the work is done and nothing got broken.

I am going to gently pound the bearings back into the case, like the book suggested. Looking at all those different Churchill tools they have to remove the circlip or press in a bearing or to hammer on the input shaft. I feel a little cavemanie without the special tools. But, seriously, I am carpenter and feel ok with a block of wood and hammer and this stuff is not that difficult to move, so I will be ok without the Churchill tools.

What do people suggest for sealing those paper thin gaskets that come with a transmission gasket set? The surfaces are very smooth and should mat up fine. I am not sure if originally the gaskets were put on dry or wet or something sprayed on them.

Steve

 

[CJD]

I used some gasket sealer on the thin gaskets, just because the old mating surfaces aren't as smooth as they once were. A thin bead on each side is plenty.

The only tools you really need for tranny work is a press, (with a bearing separator if you plan to re-use the bearings), and a good snap ring pliar.

My Chinese press cost $99 over 40 years ago. I have replaced the jack 3 times, and had to replace the thin tubing in several places with solid steel. It is one of those tools that spends most of it's time getting in the way, but when you need it, nothing else replaces it!