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ya know, thinking back I think we just used grade 8 bolts. The converter called for a different size than what I had, and a different size than the "Gm torque converter bolt" pack at the parts store. With that being said though, I don't remember putting loctite on them. If they've loosened up, could the noise be fixed by simply applying loctite and torquing back down (assuming no metal found in pan/filter)
As long as the bolts that you used were the proper thread and pitch, Grade 8 bolts with Loctite Blue should be fine torque to specified value. I would still verify the condition of the fluid in the transmission pan and engine oil filter. I would start with checking the torque converter bolts. I will get the information together and post it up later as I have work to do on the farm 1st.
As long as the bolts that you used were the proper thread and pitch, Grade 8 bolts with Loctite Blue should be fine torque to specified value. I would still verify the condition of the fluid in the transmission pan and engine oil filter. I would start with checking the torque converter bolts. I will get the information together and post it up later as I have work to do on the farm 1st.
I'm fairly certain loctite was not used the more I think about it.
I'm going to put it up in the air and see if I can find anything obvious. If I can, Ill address it then go ahead and drop the pan. If I can't, then I'll schedule it in to the transmission shop more than likely.
It's frustrating for multiple reasons, but ironically I'm seeing on the internet that this is a common GM/TH400 thing and not a big deal. Well, as much as I'd like to believe that..it shouldn't make a noise, period.
If you have a helper you should be able to put it up in the air and start it and use a stethoscope to see if it is indeed coming from the transmission.
Personally I have never heard of loose converter bolts causing damage to the front pump. They typically make a rattling noise. The hydraulic pressure in the converter is constantly pushing the converter towards the flexplate.
Not sure what the service manual says but I have never used Loctite on converter bolts even in my race car. There really is not that type of strain on them.
Blue Loctite is just good practice on driveline parts, converter, UJoint saddle straps etc...Yes if torqued properly they should stay put. Key word should.
I worked and ASE trained in several big truck shops. All driveline bolts either had the blue (or red in some cases) pre-applied to the bolts. The older trucks did not. In that case, it was required to apply the 243 removable. It's just good insurance and a pro mechanics move with a nod toward safety. A little dab will do ya.
Good idea to get it on the lift running. You will be able to isolate the noise.
If you don't already have a trans pan with a drain plug I'd suggest purchasing one. Makes trans service SOOO much easier. You can buy just the plug kit and install it in your OEM USA Delco pan.
What kind of filter is it? The cloth filters are very restrictive, they can cause a whine. Usually the whine stops once the fluid has some heat in it.
If the shop doesn’t have any useful suggestions, you might try the brass screen type filter.
I dont remember what type of filter it is, honestly. As far as the whine going away with heat..I honestly don't remember if it goes away after a while or not. I know driving across town to work, it still does it..but that's a 2 mile drive so I can't say for sure it's up to temp.
correct, it has a kit installed. If you've got upgrade info, I'll take it for sure. If imagine anything more than a stock rebuild plus shift kit would be beneficial.
Sorry it took awhile to post this for you. Here is the factory upgrade guidelines that I referred to earlier. When I redid my spare Turbo 400 Switch Pitch Transmission I used this exact information along with the torque converter from a 1965 442 Jetaway Switch Pitch to create an awesome Transmission.
Hopefully the pictures are readable. If not let me know and I'll fix it in the morning.
Are your bellhousing bolts tight?
listening to the video, in my experience the whine is in the trans. I had a TH400 in a 68 442 that had the exact same whine, consistent with RPM. The trans was built by the previous owner, shifted very tight and served me well for years and many cross country roadtrips. One day while going down the two lane at about 45MPH my dog wanted to get into the front seat. (120lb shepherd). That big dummy squeezed between the bucket seats and fell onto the shifter, pushing the **** down, and the shifter forward into park. It actually went into park at speed, which locked up therear and the car immediately swapped ends and ended up in the ditch.
Luckily I was able to drive away with no damage. Than annoying whine showed up almost immediately after, but didn't seem to make any difference in how the trans worked. For a short while. After a few hundred miles, the shifts were no longer firm, and it stared to slip like it was low on fluid but it wasn't.
I ended up pulling it out to get rebuilt, and two of the bellhousing bolts were missing, and the other four were all loose. Also, one of the alignment pins went missing? Turns out, the missing/loose bolts and hard shifts ended up cracking the case so the whole unit was scrap. We never even pulled it apart to find out what the noise was, just ended up fully replacing it. I know I put all six bolts in years earlier, but what I don't know is how long they were getting loose, or if the sudden slam into park at speed caused the damage, or a combination of the two.
Sorry it took awhile to post this for you. Here is the factory upgrade guidelines that I referred to earlier. When I redid my spare Turbo 400 Switch Pitch Transmission I used this exact information along with the torque converter from a 1965 442 Jetaway Switch Pitch to create an awesome Transmission.
Hopefully the pictures are readable. If not let me know and I'll fix it in the morning.
Are your bellhousing bolts tight?
listening to the video, in my experience the whine is in the trans. I had a TH400 in a 68 442 that had the exact same whine, consistent with RPM. The trans was built by the previous owner, shifted very tight and served me well for years and many cross country roadtrips. One day while going down the two lane at about 45MPH my dog wanted to get into the front seat. (120lb shepherd). That big dummy squeezed between the bucket seats and fell onto the shifter, pushing the **** down, and the shifter forward into park. It actually went into park at speed, which locked up therear and the car immediately swapped ends and ended up in the ditch.
Luckily I was able to drive away with no damage. Than annoying whine showed up almost immediately after, but didn't seem to make any difference in how the trans worked. For a short while. After a few hundred miles, the shifts were no longer firm, and it stared to slip like it was low on fluid but it wasn't.
I ended up pulling it out to get rebuilt, and two of the bellhousing bolts were missing, and the other four were all loose. Also, one of the alignment pins went missing? Turns out, the missing/loose bolts and hard shifts ended up cracking the case so the whole unit was scrap. We never even pulled it apart to find out what the noise was, just ended up fully replacing it. I know I put all six bolts in years earlier, but what I don't know is how long they were getting loose, or if the sudden slam into park at speed caused the damage, or a combination of the two.
To my recollection, the only issue we had was due to the flexplate being out of square when it came back from the assembly shop. We fought for a good while thinking there was an issue with the converter/pump as the bellhousing would not mate up to the block. After we finally pulled it back apart and angrily stared at it, the buddy who came over to install the converter happened to look at it from directly above and realized the outside edge where the teeth are were crooked. We picked up a new flexplate and that problem was resolved.
I'm really shooting to be able to get it up in the air this weekend and do some digging. Call it paranoia, but since seeing the suggestion of the tapping from bolts coming loose, now I swear I hear it..lol. Fortunately it's supposed to rain for the next few days, so I'm good with it being airborne. lol
Current status..its up in the air with the dust cover off. There was 1 TC bolt loose, but not much (if any) fluid inside the cover. The bolts that hold the guts to the transmission in do look a little wet, but not bad (though I'm sure the intention is for them to be dry externally)
I tightened the TC bolts down and fired the car up-the noise is still there. Kind-of expected, but figured why not.. lol.
I knew the engine engine shook a bit, but being underneath it while it's idling/revving it seems like everything is moving quite a bit. I do have a Poly Trans mount, but the engine mounts are new rubber.
I'm hoping tomorrow I can have Pops over and we can try to do a better job at pinpointing the noise.
What kind of filter is it? The cloth filters are very restrictive, they can cause a whine. Usually the whine stops once the fluid has some heat in it.
If the shop doesn’t have any useful suggestions, you might try the brass screen type filter.
revisiting this just because I keep seeing it pop up. If the current filter is the cloth lined type and/ or there's an issue with the filter tube.. would it continue to whine even once it's good and warmed up? One thing to note, a seal had already failed on this transmission last summer allowing the fluid to seep out of the vent hole in the yoke.
Well, I'm trying really hard to just he cautiously optimistic, but we just changed the filter to the screen type and took it around the block. So far, no noise.
Being that they're calling for rain every day in the 10 day outlook, I'm not sure how soon I can get it out and take it on a longer drive..but considering how easy and often it'd whine before and I got nothing this time..its definitely a step in the right direction (hopefully)
May 2nd, 2024, 05:02 AM
