egertk

I rebuilt a spare transmission this winter, I knew it was cheaper to just get a used gearbox but wanted the learning experience. I finally got the car back on the road after also installing the Re-speed R&P kit, car was driving OK, a little tough to shift... I was thinking maybe it was the new synchros needed to be worn in a little bit. Then I went to downshift from 4th to 3rd but couldn't get it into 3rd, tried 2nd... nothing... coasted to a stop... tried basically every gear and eventually got it to go. Tried driving home and got to a stop sign and the transmission made a clunk like noise and then the car stalled when I came to a stop with the clutch out. I began to think maybe this was hydraulic related as I hadn't replaced the master cylinder. I bled everything again and put in a new master clutch cylinder. (Old one had indeed been leaking) With the car on the lift... if I turn the back wheels with the car in neutral it turns the engine. It seems to be almost locked into a gear in neutral yet I can move the selector and shift into other gears, though with some difficulty. I'm totally baffled as to what might be causing this. I've tried searching here and just google in general but haven't found anything that really describes this, I don't think it's a busted shift fork because I CAN get into other gears. With the car on the lift, in neutral wheels spin at like a 4th gear speed, I can shift into 2nd though and the transmission doesn't bind up. It'll actually downshift. Any thoughts?

DriveFast7

iTrader: (1)

You need to crack it open, it's stuck in a gear.

Twilightoptics

iTrader: (1)

Yep stuck in gear. First thoughts are a broken gear shift fork, or the shift rod got wedged between two of the inner rail forks, broken, something of that sort. Definitely pull it out and pull the tail off. If the 3 forks aren't in line and it's still locked output to input, you've got to dig deeper.

egertk

Going to try and finish pulling it tonight. So I thought that if it were stuck in one gear, and you shifted it into a second gear at the same time, that would lock up the transmission?

egertk

The oil when drained wasn't full of metal also...
I'll let you guys know what I find when I crack the case.

j9fd3s

iTrader: (3)

that is correct. so it might be that the bearing between the input shaft and the tailshaft is bad, or the end play is wrong, or something like that....

Twilightoptics

iTrader: (1)

When you shift into 2nd with the wheels in the air, is it still turning at a '4th gear speed' or slower relative to the engine?

egertk

It would turn slower. Pulled the tranny... pulled the tailshaft piece and found some slivers of metal so something inside if f'd. I'm short on time to do a full tear down and diagnose where things went wrong, as I'm supposed to be moving this week. So I took the old tranny, which was fine, just worn synchros and worn tailshaft bushing. Swapped the tailshafts on the two trannys and put the old one back in. I hadn't really cracked it open so figured that should be all fine. Had it on the lift, started it up, clutch in, go to ease out on the clutch listening for noise... loud growl in neutral or any gear when you let up on the clutch pedal and it doesn't go away when the clutch pedal is fully released. I didn't touch the internals of this transmission, so my only guesses are. Somehow the input shaft got whacked or something during removal or installation. Or... I had it stored with the bellhousing down, tailshaft up on a couple of wood blocks, I drained the oil before pulling it from the car but you never get every drop. So maybe while sitting for the last couple of months all the oil that was left in there slowly seeped down into a bearing carrying with it some bits of metal?

egertk

So I tore apart the first transmission, the one that was turning in neutral. Took off the bellhousing and the tailshaft housing so that all I've got the gear stack all together. Looking at all of the gears, inspecting the input shaft bearing, etc. I couldn't see anything glaringly wrong. There's no carnage, in fact most of the metal inside is brass. The only way i can seem to replicate the sensation is if I apply aft pressure on the input shaft while I spin it, thus making it too tight with the output shaft/gearstackup. That input shaft bearing has two circlips one for the outer race that presses against the inside face of the bellhousing and one that prevents movement of the inner race on the input shaft. I don't recall you being able to adjust the "depth" of the input shaft. But there is spacer that sets the depth of the output shaft with respect to the bearing housing. I used the same one that came with the transmission, is there a chance this needed to be swapped to a different thickness spacer?

egertk

I was about to call it a night when I noticed the following. Some marks on the backside of the 1st gear and some weird wear on the input shaft gear. (Not sure what specifically that's called) here's some photos.



The only way I could see those marks on the back side of the gear forming would be if the input shaft was basically all of the way out (forward) as I've shown in the picture. I don't understand how that would happen though.
(Also is that 1st gear as I've labeled it? I think that's actually 4th now that I think about it...It's been a while since I had this thing apart)

j9fd3s

iTrader: (3)

you're right that's 4th. the only thing i can think of is that when you put the roller bearing in the center countershaft spot, its actually narrower than the double row ball, so you need to use the spacer.

egertk

It still seems like this sort of offset between the two shafts is... well impossibly large. I have to pull out the input shaft a good 1/8th inch (forwards) to make contact between the countershaft gear and the back of 4th. My other thought was... what if the input shaft was set too deep into the case? I found a description of something similar to what I experienced from a toyota forum. If I push hard on the input shaft, pushing it tight against the output shaft, it locks in both input and output shafts as if they are one shaft and essentially you get 4th gear. Which, is what I had experienced with the car in neutral. If that were the case you'd still be able to shift into other gears, through with great difficulty (you'd have to overcome that tight friction between the input and output shafts).

This is the rebuild kit I got. http://www.autozone.com/autozone/par...36_14444_5207_
It had one needle bearing that didn't seem to replace anything and it didn't come with a new circlip for the input shaft bearing. I need to check when I get home tonight, but I'm wondering if perhaps the groove on the new input shaft bearing might be wider than the circlip and therefore allowing the bearing to be set too deep?

Can somebody verify what bearing I should have for the input shaft?

egertk

Also, j9fd3s, not sure what you're talking about with the double row ball bearing? I didn't have any double row ball or roller bearings in this tranny.
(Image of rebuild kit before it was installed)

Twilightoptics

iTrader: (1)

I know they're old bad pictures but here is what it's supposed to look like.

egertk

Well all of my gears and everything appear to be in the correct place. I took before pictures also that I've been going over, I can't see that I've missed anything. Though I did just check how tight of a fit that large circlip has withing the outer groove on the input shaft bearing. It's very loose! As stated above, the rebuild kit didn't come with a new clip, so I used the old one. It fit snug when the bearing was in, meaning the bearing was pressed probably further into the case than it should have been. I'm thinking this might have been my problem, could somebody confirm this suspicion?

Twilightoptics

iTrader: (1)

I'm wondering about the input shaft pocket bearings. When not in gear aka all the sliders are in their neutral detent positions, the input should spin freely. It's turning all the gears and the counter shaft whenever it turns. Usually the mainshaft is easier to turn than the input because its just turning the hubs and sliders. How's the snout of the mainshaft where the bearing rides look?

Did you get the detents and springs in the hub/slider assembly in properly? It should kind of snap into neutral and into the gears.

j9fd3s

iTrader: (3)

the bearing in the top row center is a double row ball, the aftermarket ones have that crappy plastic race too. the factory bearing is a roller. the widths are different between the two bearings so there is a spacer for the roller bearing.

you should also buy the circlips for the shafts, they are cheap

egertk

So then, should I have not re-installed the spacer on that shaft then?

j9fd3s

iTrader: (3)

well there is a washer on each side of the bearing (maybe its just one side, its been a while) but on the roller bearing transmissions you need an extra spacer too. so if your trans was rebuilt after 1987 (remember they were doing this under warranty), it could have had the roller.

egertk

Hmmm yeah I know nothing of the history of this transmission, I got it off a '83 that a guy here was parting out. I'll take a look at the bearings I pulled out of the transmission. As I recall though all of the bearings matched up with each other (new to old).

egertk

So upon further investigation it appeared that my hunch that the input and output shafts were just being pressed together too tight when I bolted the case together. I think that the rear bearings weren't pressing deep enough into the housing or something? I managed to get all the bearings set properly, things turned nice and freely with the whole trans sitting in my massive vice all bolted together. Re-installed everything into the car, drove it on the lift for a while, noise in neutral was gone!. Everything felt good, shifted fine, so I took it for a spin. Like a half mile loop around my area I like to road test on. About 1000 feet from my street on the way back I was in third gear and I noticed the shifter basically banging fore and aft... I slipped it back into neutral and it wouldn't go easily into any gear from that point and again stalls in neutral and after coasting down my street into my garage and putting it back on the lift it's pretty clear the shafts are joined up somehow again. I can get it into gear but it's not happy to do so. I'm so frustrated with this at this point especially since I'm in the midst of moving and will be uninstalling my lift later this week and the new place doesn't have a garage for it (yet anyways). Any thoughts?

Also checked the old bearing to the new, both are the double roller bearings, and I replaced all of the spacers that I removed in the same order.

Twilightoptics

iTrader: (1)

If they were jamming together you should be able to stop the car and let the clutch out in neutral. That would pop them free. If they are bound so hard that it kills the engine, then you'd have to beat them apart when the trans was on your bench.

egertk

So what caused them to jam up though in the first place? Like I said the trans felt like a brand new gearbox for the the first 90% of my road test.

Twilightoptics

iTrader: (1)

I'm not convinced it's jammed in the input shaft. The forces don't make sense.

Banzai

iTrader: (13)

If I understand correctly, you rebuilt a spare transmission that you have no prior history or knowlegde of. This is what you've installed and are having trouble with? Is it possibile it was somehow incorrectly assembled when you bought it and you have just been repeating the same unknown mistake(s)? Have you compared the assembly to an actual factory parts manual/breakdown? A small shim out of place can mean the difference between smooth shifts and a broken pile of smelly bits.