CK5
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how can i get more power from my 454?
- Thread starter the_blaze
- Start date
The o-ring? Yes you need to pull the trans and converter, but you would not need to take the trans apart. It is the o-ring on the input shaft you can see before you slide the converter over it. If that is damaged the TCC won't work correctly and could shudder. In fact, if I remember correctly with the 4L80E the TCC pressure circuit actually unlocks the TCC, so without pressure building up on the back side it would try to lockup. It probably works the same with with a 4L60E or 700R4, but I am not 100% sure on that.
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Even if the transmission hydraulic circuit wants to engage the TCC, the solenoid still wins, so pressing the brake pedal in slightly would disable the lockup. You're thinking it's chatter from the TCC? I don't see any other parts that are engaged in 2, 3 and 4, but not 1.
But this sounds like a double failure because not only would the O-ring be losing pressure, but something would be trying to cause lockup under acceleration.
Are all the factory lockup parts in place, like vacuum switch and brake switch? Is this transmission original to the truck or did it come from a TBI truck?
But this sounds like a double failure because not only would the O-ring be losing pressure, but something would be trying to cause lockup under acceleration.
Are all the factory lockup parts in place, like vacuum switch and brake switch? Is this transmission original to the truck or did it come from a TBI truck?
The only reason it's possible it's chatter from the TCC is because he said it goes away if he locks up the TCC, but he also said....
...so who knows.
That chart shows all of the clutches and bands except the TCC clutch, it could be 1 and 2, not just 1, I am not 100% sure on that. But if the o-ring is leaking it may not matter what gear it is in circuit wise. But the lower the gear he is in, the more leverage the converter has so it's less likely to slip.
The o-ring seals pressure on the back side to allow the TCC to unlock. I think its backwards of what you would expect. If the o-ring is damaged then it can't build pressure on the back side to unlock, so the pressure from the front side would keep it trying to lock, and a partial pressure on the backside do to the leaking o-ring would also allow it to try and lock. Now, if you engage the TCC with the switch, and trip the solenoid valve to open and allow all the pressure off one side, then it would just lockup and not shutter. Basically, engaging the solenoid makes the o-ring temporarily unnecessary by letting the pressure out, not the other way around.
So the o-ring losing pressure would try to cause lockup, it would not require anything else but the o-ring losing pressure.
If it was the crank or engine it would shake in neutral and park too.
If it was the driveshaft or axle it would change with road speed, but not gear or engine RPM.
Something that changes based on gear regardless of engine RPM or vehicle speed sounds like something in the trans.
If the blaze is confident that locking the TCC eliminates the shake or shudder or whatever it is, then I would be seriously looking at that o-ring and the converter. If he is not sure, then back to the drawing board.
...so who knows.
That chart shows all of the clutches and bands except the TCC clutch, it could be 1 and 2, not just 1, I am not 100% sure on that. But if the o-ring is leaking it may not matter what gear it is in circuit wise. But the lower the gear he is in, the more leverage the converter has so it's less likely to slip.
The o-ring seals pressure on the back side to allow the TCC to unlock. I think its backwards of what you would expect. If the o-ring is damaged then it can't build pressure on the back side to unlock, so the pressure from the front side would keep it trying to lock, and a partial pressure on the backside do to the leaking o-ring would also allow it to try and lock. Now, if you engage the TCC with the switch, and trip the solenoid valve to open and allow all the pressure off one side, then it would just lockup and not shutter. Basically, engaging the solenoid makes the o-ring temporarily unnecessary by letting the pressure out, not the other way around.
So the o-ring losing pressure would try to cause lockup, it would not require anything else but the o-ring losing pressure.
If it was the crank or engine it would shake in neutral and park too.
If it was the driveshaft or axle it would change with road speed, but not gear or engine RPM.
Something that changes based on gear regardless of engine RPM or vehicle speed sounds like something in the trans.
If the blaze is confident that locking the TCC eliminates the shake or shudder or whatever it is, then I would be seriously looking at that o-ring and the converter. If he is not sure, then back to the drawing board.
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Even if the transmission hydraulic circuit wants to engage the TCC, the solenoid still wins, so pressing the brake pedal in slightly would disable the lockup. You're thinking it's chatter from the TCC? I don't see any other parts that are engaged in 2, 3 and 4, but not 1.
But this sounds like a double failure because not only would the O-ring be losing pressure, but something would be trying to cause lockup under acceleration.
Are all the factory lockup parts in place, like vacuum switch and brake switch? Is this transmission original to the truck or did it come from a TBI truck?
Its a retro kit. the jimmy is a 1978 and the trans is out of a 1986. there is no brake switch or any of that. It was build to have a one wire on off switch to lock the torque converter. I swear when I turn the lockup on it goes away. I will try to drive it a little more and do some more testing to see if i can confirm anything else.
I wonder if the seal is damaged, the torque converter has been in and out probably 5 times since the trans was rebuilt. they also had a plug in it while the last torque converter was out.
In park the truck has a decent shake at 2200rpm... but in neutral it does not... what does that mean?
Also If I powerbrake it in gear holding 2200rpm ish no shake (in first gear...)
Phantoms I tell you phantoms!
Also If I powerbrake it in gear holding 2200rpm ish no shake (in first gear...)
Phantoms I tell you phantoms!
Is that true? I always thought losing that o-ring meant you lost lockup and it disengaged because of spring pressure. I don't think pressure unlocks it, just lack of pressure. The solenoid vents the lockup pressure to the pan. We need Ducato...
My thought was that a bad oring would lead to low pressure to the TCC, letting it chatter. The TCC isn't designed to hold high torque, so if lockup is being commanded under acceleration, it certainly could chatter.
At any rate, just having a lockup switch is kind of hack. It would only really work like that with an 87+ TBI version trans that has ECM control of lockup. For all of the carb trucks, there is a hydraulic circuit to get lockup pressure, plus the electrical side controlling the solenoid.
If it is shaking in park then the forward clutch is not supposed to be engaged, and so even if the TCC was on it wouldn't matter. So if it is shaking in park then I think it is more likely it is in the engine. If you got a new crank and pistons and used the old rods and didn't check the balance then that could be it. Plus the balancer and flexplate need to match the crank on the external/internal balance deal. Factory 4" stroke BBC cranks are externally balanced and require a balancer and flexplate that offset the balance. Although its hard to diagnose if your symptoms are changing, and shaking in park but not neutral makes no sense, if the vehicle isn't moving either time. The hydraulic circuit is the same for both the only difference is the parking pawl is engaged in park.
Luke, I may be wrong. I checked my ATSG book for the 4L80E (700R4 probably works similar), and in the symptom diagnosis section, it describes what you are saying, if the o-ring is damaged then you won't have lockup or you will have a soft lockup. So I must be getting old and remember something else or something, I am not sure. Ducato would know for sure, he does that every day, its been 2 or 3 years since I've had a trans apart. I feel like an idiot that I was handing out wrong information but after you questioned me I looked it up, and I think you are right, and I was wrong.
So with that information I think it is unlikely it is the o-ring on the shaft, especially since the blaze now found it shakes in park.
I took it to the trans shop today.... after driving for 30 mins the shake changed... now no matter what throttle im giving it it has a shake around 2,000 to 2,200 RPM and IT STOPPED SHAKING UNDER HARD ACCELLERATION IN SECOND GEAR PLUS.... WTF! of course the issue would go away or totally change because its going to a shop.... I would really like it if this thing would just make up its mind and run or break again so i have a positive problem to fix.
Hopefully the transmission shop can shed some light on this...
Hopefully the transmission shop can shed some light on this...
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If you are now saying it shakes in park then its probably not the trans....
unless the TC is unbalanced right? the reason I ask is rotating the TC seemed to change the shake... and the shop that built the engine balanced it ( or so he claims) he said it might be possible there is an issue with the flex plate but he thinks its more than likely further down the line. With that said if there is an issue with the engine the last guy to admit it would probably be the machine shop...
Lesson learned... leave everything stock... LOL
What I dont understand is why would it suddenly change? Why would it come and go or change? Did it need to work out and settle something somewhere? or is the universe really just messing with me?
Lesson learned... leave everything stock... LOL
What I dont understand is why would it suddenly change? Why would it come and go or change? Did it need to work out and settle something somewhere? or is the universe really just messing with me?
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If the new torque converter is out of balance that could make it shake yes. However, rotating it shouldn't change anything as the engine is supposed to be balanced on its own.
Did you verify the torque converter pilot is engaging into the back of the crank? That is supposed to keep the torque converter centered.
Did you verify the torque converter pilot is engaging into the back of the crank? That is supposed to keep the torque converter centered.
I have been 100% hands off on the assembly and testing this time. I'll ask and see what they say. It's sitting at the transmission shop overnight they are going to do a diagnostic on it tomorrow to see if they can put their finger on it.
Let's say worst case scenario, the engine is having a balancing issue, is there any way to fix that?
Could a tune or the timing cause it to shake at certain rpm?
Not unless it's got a miss under certain conditions, but you'd hear/feel that.
If the engine rotating assembly itself is out of balance, then, unless it has the wrong balancer or flexplate that can simply be swapped, the only way to fix it is to tear it apart and have it balanced with bob weights, etc after weighing all the pistons, rods, rod bearings, piston rings, etc.
But before you do that you could check it by running the engine with the trans disconnected, that would rule out the converter.
Good luck, diagnosing stuff without actually feeling, hearing, seeing, and sometimes smelling it yourself is not very reliable.
But before you do that you could check it by running the engine with the trans disconnected, that would rule out the converter.
Good luck, diagnosing stuff without actually feeling, hearing, seeing, and sometimes smelling it yourself is not very reliable.
Yeah I just haven't had the time... I wonder if I can unbolt the tc and slide it back and run it to see if I can get it to vibrate. If the engine isn't balanced should the machine shop be responsible?
You could try that, but there is a risk the converter will catch the flexplate and something could get damaged. Might be fine, might not. If it catches it might just start spinning and not damage anything too, but that is a risk you have to decide you want to take.
And that depends on what you told them to do. If you told them to use a differnet crank and not to balance it then thats not their fault. If they told you to use a different crank and not balance it then that could be on them. Personally I wouldn't use a different crank and not balance it unless it was the exact same GM part number and I knew it was 100% original.
And that depends on what you told them to do. If you told them to use a differnet crank and not to balance it then thats not their fault. If they told you to use a different crank and not balance it then that could be on them. Personally I wouldn't use a different crank and not balance it unless it was the exact same GM part number and I knew it was 100% original.
Yeah he said it was a factory replacement and he said he balanced the motor. I
The transmission shop is being super shady... they had me drop it off at open yesterday, they didn't get around to looking at it. So I left it over night because he said they would get it done today.... I just called and he said we drove it a few times but we aren't 100% sure yet what's going on. So he needs "more seat time" with the vehicle, he wants it again overnight. He asked if I was in a hurry I said I definitely need it back tomorrow. He said ok but if something happened he could meet me Saturday to get it... I seriously get the feeling these guys are just joyriding my truck and want it over the weekend to drive around. Maybe I'm being crazy but maybe not. Just seems shady especially because this is just a diagnostic that they are supposed to be doing.
If they're a good shop they could just be busy....
Or they're just being lazy...
Or they really don't know what's going on with it, but it sounds like they at least were able to observe/feel the problem. If they are genuinely trying to fix it and not out 'joyriding' you don't want to rush them super hard as that's when stuff gets screwed up.
Or they're just being lazy...
Or they really don't know what's going on with it, but it sounds like they at least were able to observe/feel the problem. If they are genuinely trying to fix it and not out 'joyriding' you don't want to rush them super hard as that's when stuff gets screwed up.
