t56 popping out of 1st, internals look fine?
02-20-2015, 08:12 PM
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t56 popping out of 1st, internals look fine? Hey guys, I have an 01 Corvette driveline in a hot rod truck, LS1, t56, stock rear end royal purple sychromesh oil.
1st gear pops out and grinds pretty much every time I select 1st and use some throttle (apply torque). The weird part is that if I select 1st and hold the shifter in 1st (pushing on the gate) and slowly let out the clutch, it will make a loud clunk. After the cluck it will operate as it should, I can burn the tires or whatever, and shift into 2nd like normal...
Also, when engine braking like when rolling up to a stop sign, I can stick it in 1st and let the clutch out while rolling slow and it will still pop out and make all manner of grinding noise. Again, once I've clunked it into 1st, I can decelerate just fine...
All the other gears work normally, and the clutch works ok as well...
I took the trans apart and can't find anything particularly wrong looking, the sliders look fine on the main 1-4 cluster, gears don't look weird, the synchros will brake the gears if you push on them with the sliders. Hell, reverse looks worst, and I've never had a problem with it...
I was reading that possibly the linkage, forks, sliders, keys or synchros could be the culprits, but they all look fine to me…
1st gear
IMG_7437m by Der E30, on Flickr
2nd gear by Der E30, on Flickr
IMG_7442m by Der E30, on Flickr
IMG_7441m by Der E30, on Flickr
IMG_7439m by Der E30, on Flickr
1/2 fork, looks fine to me…
IMG_7435m by Der E30, on Flickr
3rd
3rd:4th slider by Der E30, on Flickr
3-4 slider from 3rd side… Most of the sliders look more or less like this, pretty good as far as I know...
3rd slider by Der E30, on Flickr
I’m thinking of getting billet keys, and brass fork-slider things, plus the steel viper 3-4 shift fork. Maybe add a 1-2 shift fork to the list also as a “while I’m here” mod?
I’m at a loss as to what’s wrong, I thought once I had it apart it would be obvious, but it isn’t. Shifter? New 1-2 slider and synchros?
What am I missing????
1st gear pops out and grinds pretty much every time I select 1st and use some throttle (apply torque). The weird part is that if I select 1st and hold the shifter in 1st (pushing on the gate) and slowly let out the clutch, it will make a loud clunk. After the cluck it will operate as it should, I can burn the tires or whatever, and shift into 2nd like normal...
Also, when engine braking like when rolling up to a stop sign, I can stick it in 1st and let the clutch out while rolling slow and it will still pop out and make all manner of grinding noise. Again, once I've clunked it into 1st, I can decelerate just fine...
All the other gears work normally, and the clutch works ok as well...
I took the trans apart and can't find anything particularly wrong looking, the sliders look fine on the main 1-4 cluster, gears don't look weird, the synchros will brake the gears if you push on them with the sliders. Hell, reverse looks worst, and I've never had a problem with it...
I was reading that possibly the linkage, forks, sliders, keys or synchros could be the culprits, but they all look fine to me…
1st gear
IMG_7437m by Der E30, on Flickr
2nd gear by Der E30, on Flickr
IMG_7442m by Der E30, on Flickr
IMG_7441m by Der E30, on Flickr
IMG_7439m by Der E30, on Flickr
1/2 fork, looks fine to me…
IMG_7435m by Der E30, on Flickr
3rd
3rd:4th slider by Der E30, on Flickr
3-4 slider from 3rd side… Most of the sliders look more or less like this, pretty good as far as I know...
3rd slider by Der E30, on Flickr
I’m thinking of getting billet keys, and brass fork-slider things, plus the steel viper 3-4 shift fork. Maybe add a 1-2 shift fork to the list also as a “while I’m here” mod?
I’m at a loss as to what’s wrong, I thought once I had it apart it would be obvious, but it isn’t. Shifter? New 1-2 slider and synchros?
What am I missing????
Last edited by DER E30; 02-20-2015 at 09:05 PM.
02-21-2015, 10:40 AM
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It could be I suppose. I was reading that the royal purple was bad for the paper blocker rings but mine has black blockers which iirc are the carbon... My diff is the late '01 style 3 rib one which seems to back up that it's a late model...
I'm baffled that nothing seems wrong. I was reading that the shift forks could get sloppy on the shafts and once again, mine are tight on the shaft...
Put it back together with something other than royal purple?
Around two years ago I filled it with the royal purple and haven't really driven it at all, mostly sitting while I built the truck around it. It's seen maybe 700 miles max since I've owned it, with ~75 k on it in the previous life as a corvette. The problem started a few weeks before the goodguys show in puyallup last year and I pretty much put it away after that.
It's super frustrating because it will act like it's in gear and let you move with the clutch but once you roll on the gas it will pop and buzz.
I'm not even a transmission beater, I've never powershifted the trans, and haven't even rev matched 1st like I do the other gears. I usually double clutch down shift as a force of habit.
I'm baffled that nothing seems wrong. I was reading that the shift forks could get sloppy on the shafts and once again, mine are tight on the shaft...
Put it back together with something other than royal purple?
Around two years ago I filled it with the royal purple and haven't really driven it at all, mostly sitting while I built the truck around it. It's seen maybe 700 miles max since I've owned it, with ~75 k on it in the previous life as a corvette. The problem started a few weeks before the goodguys show in puyallup last year and I pretty much put it away after that.
It's super frustrating because it will act like it's in gear and let you move with the clutch but once you roll on the gas it will pop and buzz.
I'm not even a transmission beater, I've never powershifted the trans, and haven't even rev matched 1st like I do the other gears. I usually double clutch down shift as a force of habit.
Last edited by DER E30; 02-21-2015 at 11:47 AM.
02-21-2015, 08:54 PM
#5
You've got some pretty bad wear on the 1st gear synchro teeth. The teeth need the characteristic trapezoidal coffin shape to lock the slider in under power and I see that is nearly gone on the flanks. I'd suspect a bent shaft might cause wear like that.
02-21-2015, 11:01 PM
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So a new 1-2 slider assembly?
02-22-2015, 03:37 AM
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So I got the 1st gear and slider off the mainshaft... NEW PICS!
IMG_7456m by Der E30, on Flickr
IMG_7457m by Der E30, on Flickr
IMG_7454m by Der E30, on Flickr
IMG_7453m by Der E30, on Flickr
IMG_7450m by Der E30, on Flickr
IMG_7449m by Der E30, on Flickr
The more I look at the teeth on 1st gear itself, the more I think that the circled area could be the issue, the teeth all look the same, almost rounded off right on the corner...
IMG_7446m by Der E30, on Flickr
IMG_7459 by Der E30, on Flickr
IMG_7461m by Der E30, on Flickr
IMG_7460m by Der E30, on Flickr
Am I going nuts or is that the problem and I need another gear and slider? Is that rounded area just enough to let me feel like its in gear but not be? I don't think its a synchro problem at all as it doesn't grind trying to get in gear, it just throws the lever out. But why does it clunk then be in gear like it should work in the first place?
IMG_7456m by Der E30, on Flickr
IMG_7457m by Der E30, on Flickr
IMG_7454m by Der E30, on Flickr
IMG_7453m by Der E30, on Flickr
IMG_7450m by Der E30, on Flickr
IMG_7449m by Der E30, on Flickr
The more I look at the teeth on 1st gear itself, the more I think that the circled area could be the issue, the teeth all look the same, almost rounded off right on the corner...
IMG_7446m by Der E30, on Flickr
IMG_7459 by Der E30, on Flickr
IMG_7461m by Der E30, on Flickr
IMG_7460m by Der E30, on Flickr
Am I going nuts or is that the problem and I need another gear and slider? Is that rounded area just enough to let me feel like its in gear but not be? I don't think its a synchro problem at all as it doesn't grind trying to get in gear, it just throws the lever out. But why does it clunk then be in gear like it should work in the first place?
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02-22-2015, 06:09 PM
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I'll look into this when I get home! Good call! I checked the fork on the shaft last night and it was pretty dang tight on there, basically no slop but the S link thing I didn't look at.
02-22-2015, 06:24 PM
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What to look for on the detent plate? It looked ok when I took it out but I don't know what I'm looking for.
02-24-2015, 01:06 PM
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I had a transmission builder friend look at 1st gear and the slider. He said to replace both as the teeth's back taper looks worn and that is why it pops out...
So doing that. Will bump thread when its all back together.
So doing that. Will bump thread when its all back together.
Last edited by DER E30; 02-24-2015 at 06:17 PM.
02-25-2015, 07:14 AM
#13
What is the original year of the transmission?(edit I see it's an 01') I know I had a friend with a 98' corvette that would do this also. I've built quite a few transmissions over the past 15 years and I'm not seeing the super bad wear you guys are talking about. From the description in your first post it almost seems like the slider is not fully pulling down over the teeth and when you hear/feel it clunk that's what happens. Hard to say, but if you get a new setup lets look at the teeth up close if you have time to post it.
There will always be some rounding off on a gear that been buzzed a few times, but I don't always throw them out either. I do notice the wear at the top corners of the gear, but do you not see any of this on the other gears to compare it to? I's not like the slider just sits at the very end of the teeth, it's going to bottom out on the gear and you still have some of the correct shape to the teeth to keep things together. As you said above after it's clunks in (slider bottoming out on gear) it is good. Have you made sure the shift fork has not worn by the metal S-link at all? It's a hard one to call as I know it's a pain to mess around and not get it right so sometimes new parts just make sense.
There will always be some rounding off on a gear that been buzzed a few times, but I don't always throw them out either. I do notice the wear at the top corners of the gear, but do you not see any of this on the other gears to compare it to? I's not like the slider just sits at the very end of the teeth, it's going to bottom out on the gear and you still have some of the correct shape to the teeth to keep things together. As you said above after it's clunks in (slider bottoming out on gear) it is good. Have you made sure the shift fork has not worn by the metal S-link at all? It's a hard one to call as I know it's a pain to mess around and not get it right so sometimes new parts just make sense.
Last edited by slowride; 02-25-2015 at 07:29 AM.
02-25-2015, 02:06 PM
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What is the original year of the transmission?(edit I see it's an 01') I know I had a friend with a 98' corvette that would do this also. I've built quite a few transmissions over the past 15 years and I'm not seeing the super bad wear you guys are talking about. From the description in your first post it almost seems like the slider is not fully pulling down over the teeth and when you hear/feel it clunk that's what happens. Hard to say, but if you get a new setup lets look at the teeth up close if you have time to post it.
There will always be some rounding off on a gear that been buzzed a few times, but I don't always throw them out either. I do notice the wear at the top corners of the gear, but do you not see any of this on the other gears to compare it to? I's not like the slider just sits at the very end of the teeth, it's going to bottom out on the gear and you still have some of the correct shape to the teeth to keep things together. As you said above after it's clunks in (slider bottoming out on gear) it is good. Have you made sure the shift fork has not worn by the metal S-link at all? It's a hard one to call as I know it's a pain to mess around and not get it right so sometimes new parts just make sense.
There will always be some rounding off on a gear that been buzzed a few times, but I don't always throw them out either. I do notice the wear at the top corners of the gear, but do you not see any of this on the other gears to compare it to? I's not like the slider just sits at the very end of the teeth, it's going to bottom out on the gear and you still have some of the correct shape to the teeth to keep things together. As you said above after it's clunks in (slider bottoming out on gear) it is good. Have you made sure the shift fork has not worn by the metal S-link at all? It's a hard one to call as I know it's a pain to mess around and not get it right so sometimes new parts just make sense.
Its weird, if I didn't know that it pops out of 1st I would think the trans was practically mint.
Looking at the fork pads, they also look pretty good. Not broken or anything, and they still fit pretty tight to the slider...
Would bronze pads help as bronze squishes less than plastic? I'd love to not but a gear and slider as that's ~255. Would it be better to buy a short shifter kit and bronze pads with that money? I'm not opposed to spending the money, just I'm still trying to finish the truck and the money could be used in other places...
Edit: Could the mainshaft have too much slop and need reshimmed? Or would that not cause an issue like this?
02-26-2015, 02:49 PM
#15
Give d&d performance a call. They usually have good deals on used take outs. I used to get inputs and clusters for Vipers around $150. Gears used to be $50 ea.
edit: never mind. Just visited their site. Boy T56 prices have gone up.
edit: never mind. Just visited their site. Boy T56 prices have gone up.
05-05-2015, 08:03 PM
#17
lol, yeah it's pretty insane now a days. Honestly since you already have it apart I'd just do 1-2 slider, new blockers and anew 1-2 fork. RP is ok in your trans, but most people still recommend a mineral trans fluid for that generation t56. 1st itself looks ok to me, but I'm not a gear cutter.
05-05-2015, 08:16 PM
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So I put it back together with bronze fork pads, billet keys, new 1st gear, new 1-2 slider, short shifter and new fluid. And its been sitting while other things have happened. So I don't know if it was the fix or not, but I'll keep you guys posted when I take it out and find out!
I had a guy on another forum say that he thinks the whole thing needs to be reshimmed, that's the only other idea I've heard that makes sense.
I had a guy on another forum say that he thinks the whole thing needs to be reshimmed, that's the only other idea I've heard that makes sense.
05-06-2015, 03:21 PM
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If you are using a Corvette shifter and rod, you need set the shifter:
place the trans in neutral
there is a pin on the shifterpod that sets the shifter to the neutral position
then fasten the shift rod to the trans and shifter pod
then you remove the pin on the shifter.
This insures you have enough shifter throw front and rear to get and stay in gear.
place the trans in neutral
there is a pin on the shifterpod that sets the shifter to the neutral position
then fasten the shift rod to the trans and shifter pod
then you remove the pin on the shifter.
This insures you have enough shifter throw front and rear to get and stay in gear.
05-06-2015, 03:54 PM
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If you are using a Corvette shifter and rod, you need set the shifter:
place the trans in neutral
there is a pin on the shifterpod that sets the shifter to the neutral position
then fasten the shift rod to the trans and shifter pod
then you remove the pin on the shifter.
This insures you have enough shifter throw front and rear to get and stay in gear.
place the trans in neutral
there is a pin on the shifterpod that sets the shifter to the neutral position
then fasten the shift rod to the trans and shifter pod
then you remove the pin on the shifter.
This insures you have enough shifter throw front and rear to get and stay in gear.