TH350 Mystery

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Raider L

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I've got a problem I need help with my '74 TH350, with 165K on it with no prior problems up to now. It was over hauled back in 1992 and we put a 2000 stall converter in it to unload it from the extra horse power the engine had when we over hauled the engine with all the performance stuff we did to it. I have had this truck for 25+ years. It's a high perf. street machine but I didn't build it to race although it most definately could. I enjoy just knowing the power that we built into it. My hot rodding friends pick on me that I drive it like a old lady going to church. Recently I changed fluid after taking the pan off for a few days. I did not know the trans took as much fluid as it ended up taking. All I had ever done was change the fluid normally. I didn't remember how much we had put in it when we built the truck and put the trans. in. If I had bothered to check the factory manual I clearly says 20 pints, that's 10 qts. plus another four qts. for the converter. The problem I'm having now I don't think has anything to do with the trans being broken because when I'm driving it the trans does okay and operates normally. But for some reason it will shift back to second and I'll have to manually shift to neutral and quickly back to third and it will shift back to third. I can deal with that because it's intermittent. The other thing it does is it will be going along and act suddenly like it's in neutral and it won't go into any gear. I'll be still rolling at street speed and it will suddenly bump into gear and will seemingly be normal. It pulls away from a stop light and shifts through all three gears and may drive a ways and then will do one of those things I mentioned.
All I did was change the fluid and I took the pan off so I could change the screen and put a new modulator valve on it. The one I took off had been on there for twenty-five years I guess it was time to change it. It has a TCI 2 qt. finned cast alum. pan on it and I put in a tubular trans crossmember with a Energy Suspension poly mount on it this last time a couple of months ago and was not driving it. All these problems started after I started driving it again. I took the modulator line off and cleaned it, all new rubber hoses, and found the new mod. valve was out of adjustment and instead of fooling around test driving it after some minor mod. valve adjustment, I just bought a new one. That one did much better. They are supposed to be set at the factory but that one was wrong. This new one was set right. There was other problems I have had with it this time but it would take up to much space to explain it, but now I'm thinking the kick down linkage is out of adjustment. I have a link on the carb that is supposed to work when you change from a 2bbl. to a 4bbl. carb. But it may still not be right. Anybody got any ideas what I can try to solve these weird shifting things going on? Especially the thing when it suddenly seems to be in neutral and goes back in gear somewhat hard. And when it's doing that it won't shift into any gear, and I'm not talking about reverse or park. It would blow the trans up but I'm referring to any of the drive gears.
 

Raider L

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I want information on specifics about what the end of the kick down cable looks like when it's in correct or what it's supposed to look like when it's connected correctly. When I got my Holley carb, a 1460? 18 something or other, it's whats called a "service replacement" 4bbl. 600 cfm vacuum secondary single pump. Both bowls are connected with a tube. The primary jets are removable in the front bowl but there is a jet "plate" in the rear bowl. The fuel hose inlet is straight in not at an angle like in what I call racing 4bbl's. It's a stock type 4bbl. that would be put back on some stock engines that would come with a Holley from the factory. I really don't know which ones that would be. Maybe some Camaro's with a better than OE setup? I don't know.
Okay, when I got that carb, from Super Shops, some of you may not remember them, or they may not have been in your city, it came with a bar with four holes in it and attaching bolts and a stud to attach the kick down link to. You were supposed to locate that stud in one of those holes where your kick down cable would need to go so it would work like it did when your engine either had another type of carb on it or was like mine when it was stock with a 2bbl. on it.
My enfine guys weren't quite sure where it was supposed to go so we just picked one of the holes and attached the link end of the kick down cable there. Well, it must have been the right place because it worked fine for 25 years, until now. When I took it off when I changed my intake gasket and reattached it I never did do the "snap lock" thing to reset it. Other things I was dealing with the trans. reseting the cable was the least of my worries, until now. I want to call Holley and ask them what is it supposed to look like. I remember there being more space at the end of the slot of the kick down link and the stud on the bar part of linkage before it came in contact with the end of the slot would start pulling on the cable. Or, and here is what I really need to know is, is that stud supposed to be pulling on the kick down cable all the time the carb linkage is coming back as you accelerate? I noticed that when I "reset" the kick down cable there would be about 3/8" of space before that stud contacted the end of the slot in the end of the kick down link. I also noticed that any movement of the carb linkage would start pulling on the kick down cable. And as I have read the only time the pull on the kick down cable will cause the trans to shift down to second would be if all the slack was taken up by the carb linkage and the last 3/8ths. would be where the kick down would take place. That's why you pull the carbg linkage all the way baxck and making sure the pedal isa on the floor and is pulling that last 3/8ths. and then the cable is properly set. The kick down cable is pulling all the time and that's what makes the trans work right. But I don't remember it being that way. It may have been but I wasn't paying attention to that over the years. Obviously I needed to have, but you know how it is. I don't have the help I once did. All those guys I used to know all moved away. One of them, who built my engine way back in 1994 is a famous drag racer now on TV. Since then I've not had to do any repairs to my engine other than normal maint.. And something like this never came up in 25 years.
 

Raider L

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Well, tomorrow I take it out on some stuff I need to do and then all three things that were a problem that are all corrected, but not together back some time ago, are all now hopefully fixed and then we'll see what's what. First it was the fluid level that wasn't right that required three fluid changes and filter changes to finally get right. Then a modulator valve I bought was out of adjustment and it caused problems until I replaced it. I was running it with the kick down linkage disconnected. I believe the modulator is now working right. Tonight I redid the kick down linkage setting, with the help of my wife as she was passing by, I grabbed her and got her in the cab to push down on the gas pedal a couple of times while I reset the snap lock. After checking it a couple of times I think it's right. With the help of some posts here, on other sites, and even reading my factory maint. book had some help in it I think I'm ready for the first test with all three things fixed I hope.

Oh yeah, would someone please direct me to instructions on how to download pictures on this site? I'm not to good with computer stuff so it's got to be simple. I downloaded a bunch of photos of that kick down link tonight and my engine so ya'll can see I'm somebody who is not entirely ignorant. Maybe some of you have this linkage I have for the kick down on your Holley.
 

Raider L

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So, Today I had to go out and do my monthly stuff. The truck started out fine for about a block! Then it started the down shifting thing again. But then it went straight to acting like it wasn't in any gear and wouldn't shift to any drive gear until I got to the end of the avenue to turn towards town. I shifted to park after stopping and started over putting it in drive. Then it seemed like it was going okay but was still a little bit like it was going to act like it wasn't in any gear again but then it bumped into gear by the time I got a couple of blocks away to the first stop light. Oh yeah, when I made my first stop getting ready to turn onto the highway to go to town as I was coming up to the stop sign it acted like it had shifted down to first, higher RPM while I was rolling and watching the tach but didn't have that hard down shift like it would have had you actually shifted to first. Man it was really acting weird. I couldn't figure out what it was doing.
So I make my turn and it shifted okay and was in third going along fine. So traffic was slowing at the next highway and I slowed down for the light, behind traffic. It down shifted okay. I made my turn and sped up because this highway has a higher speed than the one I just left and I was wondering how it was going to take shifting at acceleration. It did okay. I decided to take a shortcut instead of going to the intersection ahead and have the darn thing decide it didn't know what gear it was in, in the middle of the intersection, so I turned into a hospital parking lot and glided along in second just fine doing about 15 mph.. I cut through these big parking lots like Walmart, which in this area has a small service road around it with many turnoffs to businesses along the way so I can get to where I need to go without taking the highways with heavy traffic and lights. If your vehicle is messing up don't take the highway if you can help it. Take shortcuts where there are plenty of places to stop where you're not in traffic. You can't work on your truck with twenty cars behind you and you are under the truck on your back doing something, okay.
After I left my first stop off the darn thing drove fine after that all the rest of the day. I couldn't believe it. I actually thought, " Did the valve body and other stuff have to get used to the new kick down setting for it to work like it's supposed to?" See, I've never had this problem before and didn't have to study up on transmission functioning just to drive the truck, I just drove the truck and dealt with engine stuff all these years, not problems but regular maint. and installing upgrades and fine tuning, carb overhauling and such. I never had one single trans. problem for 25 years until now, so I don't know how this stuff is supposed to work when it's back working like it's supposed to work. Just because it's working now doesn't mean it may not mess up tomorrow like it has for the last month or so. Tomorrow we'll see if it's still working. If it is then I'm closer to getting it back adjusted properly like it was before all this stuff started.

Here's my question: There's a little bit of slack, about a half inch the kick down link has in it just before it actually starts pulling on the cable. Like, the metal kick down cable linkage is like a tube behind the flattened part in front that has the slot for the post in it. I slides atop an inner sleeve that has the cable in it. Do I need to take that slack out? There's another hole in the carb link, for attaching the kick down cable end, ahead of the one I have the post in now. But I think if I put it in that one it might be actually pulling on the cable with the carb linkage at rest. I don' t think I want it there. I may have to make a new linkage with a hole half way between the hole it's in now and that next hole ahead of it. That would remove all that little bit of slack in the kick down link so as soon as you move the carb linkage it would start pulling on the cable. There is enough space left between the end of the slot in the kick down cable linkage and the post before it starts pulling on the actual cable, to take out. Should I?
 

Raider L

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Well, I guess there are just to many people on this site to get any responses to my posts. Or you all are just to hooked on 169 characters or whatever twitter or facebook is to know what to do when you have to actually read something that isn't mostly acronyms.
I feel like someone down in the bottom of a well yelling for help. Unless someone walks by and hears me I'll never get out.
 

Rusty Nail

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Here's another pickle to keep you company down there.

Get it? Another pickle?

You must be registered for see images attach




I'm not convinced our inability to read is in play here at all. Perhaps consider a different tact.

Pretty sure everybody here has a problem of some sort...maybe a proper introduction will go over better than your thinly veiled insults Mr.Junior Member cuz ain't nobody here gonna take kindly to your tone.


xc_hide_links_from_guests_guests_error_hide_media



Tell ya what..rather than hollering from a well, why don't you try to help someone else out and make a friend first?

Just an idea..it's not much help with your new pan that is too deep and left the filter at the original installed height starving your trans of fluid.


Whatever.
Your cable is all jacked up too. How did the adjustment "magically" change after all that time?

Never mind. I don't care.

Enjoy your Portly Pickle, *****. Says here your ****'s all retarded.
Like..
Ya know?
 
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Matt69olds

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The kickdown cable doesn’t affect shift points on a 350. Basically, the kickdown cable should be maxed out at full throttle. You can leave the cable unhooked and the only thing that will happen is no full throttle downshifts.

If you pull the kickdown cable, does its nap back to its resting position? If not, then maybe the cable is binding in the casing.


Is the tube to the vacuum modulator in good condition? Is the hose connecting the tube to the engine and modulator tight and in good condition? Don’t turn the screw inside the modulator more than 2-3 turns max, either direction. The modulator adjustment will change shift points, but only a couple mph up or down. If you need bigger changes than the modulator adjustment allows, then you need to make changes to the govenor

Which brings up the next thing to look at. The governor is behind a round cover on the passenger side of the trans. There is sometimes a wire retaining clip that help holds it in place. Remove the clip, carefully tap off the cover with a wide screwdriver or chisel. The governor will then slide out. Inspect the gear, make sure all the teeth are there and not worn. Use you finger, feel the bore in the transmission case that the governor rotates on. If you feel any excessive scratches or gouges, then most likely the rear bushing of the transmission case is severely work, allowing the output shaft to move an excessive amount. Since the governor gear is driven by the output shaft, excessive movement will tear up the governor and the bore it turns in. If the bore is chewed up, your options to fix it are a manual valve body, replacing the case (th350 in good shape are getting harder to find) or you can machine your existing case for a sleeve that provides a new surface for the governor to ride on. To install the sleeve retires complete transmission disassembly.


Last idea, assuming the governor weights are free to move, the gear is in good shape, and the governor bore in the case is good, then the next thing to look at is the round cover itself. Is the cover dented or beat up? The governor can’t have a bunch of free play, you can use a punch and a hammer to dent the very center of the cover to reduce the in/out movement of the governor.
 

Matt69olds

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Jake is a good no nonsense guy. He is wealth of information. I have used some of his stuff on 4L80 builds I have been involved with.
 

gotyourgoat

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smokin' 305
Oh yeah, would someone please direct me to instructions on how to download pictures on this site? I'm not to good with computer stuff so it's got to be simple. I downloaded a bunch of photos of that kick down link tonight and my engine so ya'll can see I'm somebody who is not entirely ignorant. Maybe some of you have this linkage I have for the kick down on your Holley.
On the reply to a thread screen. There's a row of red boxes, select upload a file. Option will appear to let you browse through the file storage on your device/computer or however you are viewing. Choose browse in the pop up to let you search your files. Select files and post.
 

Raider L

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Matt69olds,

All those points about the cable condition are right, but that was one of the questions I was asking about. I don't know about unhooking the kick down and it would drive okay. I did that here recently and it ran terrible, up down shifting at random, acting like it was in neutral, then shifting suddenly , etc.. But then again my stuff never, never does like other people's stuff.
You know that little bit of movement just before the carb linkage begins to just start pulling on the cable, is that supposed to come out to, when you are adjusting the kick down cable? The cable IS adjusted correctly, except for that little bit of where the end of the physical thing that attaches to the carb linkage post. Is that little bit supposed to be adjusted out to? I could get it out but what I would have to do is take that link bar and make a slot between the one hole the post is presently in now and the next hole up I can't use because it's to far away. Then I could place the post between the two holes or where ever it would finally get all the slack out of the end and then tighten the post down right there. I read recently that "...all slack (play) should be out so that the moment the carb linkage moves it starts pulling on the cable." So, okay that means ALL the slack, not just where like you mentioned where is the slack when the linkage is at rest. After I adjusted the cable all there was left WAS that little bit where the carb linkage just moves and just as that little sliding of that end with the slot is in, is being pulled by the movement of the carb linkage off idle comes to the end of it's sliding along of the tube over the cable housing, then the carb post begins pulling on the cable as first gear is winding up from a stand still.
Today I drove the truck, after I got through putting in the air/oil separator which looks cool, and it drove fine for way after it was at operating temp. After getting the cable adjusted this last time it ran crappy until it seemed to get used to the adjustment and after that it drove normal. It drove like that today. So, other than one tiny little glitch everything was normal. So, I guess it's fixed. But after months of hell I'm gun shy and if it drives with very little problems for a month or so, and they are going to have to be very little problems, maybe not even a "problem" but a tiny glitch like today, then I deem it fixed and I can get some normal use out of it until I can save up the money to get the trans. overhauled or get a new one which might be better. But then again a expert rebuild could be cheaper. I found a guy here in town who said he'd use my parts for $950. That might be the better deal. I would like that TCI "Street Rodder" overhaul kit and a new 2000 stall "Saturday Night Special" torque converter and I'd be back to how it was twenty-five years ago.
 

Ricko1966

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The cable just makes it down shift, I suppose if you had it too tight it could be downshifting when it shouldn't but that won't make it go into neutral. You could disconnect it and drive it see if anything changes.Since all your oblems appeared after you changed your filter, I'd double check my fluid level, then if it's good I'd pull the pan and make sure my new filter was installed correctly and/or nothing's in the pan that's getting sucked onto the filter causing your transmission to starve for fluid
 

Matt69olds

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And make sure the gasket between the filter and valve body is positioned correctly
 

SirRobyn0

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The cable just makes it down shift, I suppose if you had it too tight it could be downshifting when it shouldn't but that won't make it go into neutral. You could disconnect it and drive it see if anything changes.Since all your oblems appeared after you changed your filter, I'd double check my fluid level, then if it's good I'd pull the pan and make sure my new filter was installed correctly and/or nothing's in the pan that's getting sucked onto the filter causing your transmission to starve for fluid

And make sure the gasket between the filter and valve body is positioned correctly

@Raider L Those quotes are right on the money. I'd be willing to be those downshifts aren't really downshifts it's pressure drop in the tranny. I've seen this more than once at shop, where a tranny gets serviced and the filter isn't installed correctly or for some reason the pickup doesn't seal right and it sucks air. It'll feel very similar to being quite low on fluid. And your description certainly fits that. So before you go fiddling around with any adjustments, drop the pan and change the filter again. Money is on that fixing it.

I have to agree with @Rusty Nail comments You have two threads, both asking for help on your truck. I can see no where that you have tried to help anyone else, heck the least you could have done is to introduce yourself and your truck. That's why it took so long for you to get any feedback on this post. You could be the nicest guy in the world, but it comes off as you wanting only to take from the community which is ****** and off putting to other members. For that reason this will be my last post on this thread, you got what your gonna get from me.
 

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