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Discussion Starter · #1 ·
I haven't posted in a while. I recently built a 383 and just installed it onto my TH350. I was so excited when it fired up the first time (after a faulty MSD 6A, but that's another story). Ready to pull it out of the driveway, when, NO GEARS. So I pushed it back to the house and now it's sitting and I'm all out of ideas. It'll go into park just fine. I made sure the shifter linkage is actually changing gears. I have put about 8-9 quarts of ATF in. Still nothing. When I swapped the engine, I did swap out the torque converter for a JEGS house brand one. I thought I made sure it was fully seated. After I bolted the bellhousing to the engine, I had to pull the torque converter out about .360" (which I believe is alright?). Just to double check as well, I unplugged the bottom transmission hose from the radiator and started it up and transmission fluid came flying out of the line, so I'm guessing the pump is still good. Am I missing something? Is there something stupid I forgot to hook back up after the swap? Thanks guys.
 

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I haven't posted in a while. I recently built a 383 and just installed it onto my TH350. I was so excited when it fired up the first time (after a faulty MSD 6A, but that's another story). Ready to pull it out of the driveway, when, NO GEARS. So I pushed it back to the house and now it's sitting and I'm all out of ideas. It'll go into park just fine. I made sure the shifter linkage is actually changing gears. I have put about 8-9 quarts of ATF in. Still nothing. When I swapped the engine, I did swap out the torque converter for a JEGS house brand one. I thought I made sure it was fully seated. After I bolted the bellhousing to the engine, I had to pull the torque converter out about .360" (which I believe is alright?). Just to double check as well, I unplugged the bottom transmission hose from the radiator and started it up and transmission fluid came flying out of the line, so I'm guessing the pump is still good. Am I missing something? Is there something stupid I forgot to hook back up after the swap? Thanks guys.
Is the fluid level reading full? If trans oil came out of the loose fitting. It seems to have pressure, but is it too low on fluid to maintain pressure?
 

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Discussion Starter · #3 ·
Is the fluid level reading full? If trans oil came out of the loose fitting. It seems to have [ressure, but is it too low on fluid to maintain pressure?
Every time I've checked, it's read full. Originally when everything was done with the swap, it didn't read anything. Since then, I've put in about 8-9 quarts. I'm wondering if it's slowly working it's way in? I don't understand how I could have lost that much fluid just swapping out the torque converter?
 

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You didn't but did you put about a quart of fluid in the new convertor before you installed it. And when it was installed did you make sure that it dropped completely back? Normally looking at the convertor mounting tabs and the front edge of the bell housing there should be about an inch or touch more. Once everything was in place, you should have measured the space between the mounting tabs and the flexplate. Taking that number you need to have .125 - .187 clearance from it and make up the difference with spacers.

If you have put in 8-9 quarts in and did not drain the transmission that could be an issue too, I would be surprised that you don't have fluid bleeding out of the vent at the top of the trans at this point. And lastly you didn't mention the type of shifter, but you need to verify that each gear selected (PRND21) needs to match the transmission selector - this is usually a bit easier with a helper. When you operate the selector without any linkage attached to it, each gear selection should be solid and click in place.

You said you pulled it out .360 so I assume you measured that - and that's really on the edge as I just measured one of my TSI convertors and the slot is .515 deep. That leaves you with .155 engagement (assuming that the Jegs convertor is cut to the same depth) and that just a bit over an 1/8". The simple flexing of the chassis on a rough road could cause a disengagement.
 

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Discussion Starter · #5 ·
You didn't but did you put about a quart of fluid in the new convertor before you installed it. And when it was installed did you make sure that it dropped completely back? Normally looking at the convertor mounting tabs and the front edge of the bell housing there should be about an inch or touch more. Once everything was in place, you should have measured the space between the mounting tabs and the flexplate. Taking that number you need to have .125 - .187 clearance from it and make up the difference with spacers.

If you have put in 8-9 quarts in and did not drain the transmission that could be an issue too, I would be surprised that you don't have fluid bleeding out of the vent at the top of the trans at this point. And lastly you didn't mention the type of shifter, but you need to verify that each gear selected (PRND21) needs to match the transmission selector - this is usually a bit easier with a helper. When you operate the selector without any linkage attached to it, each gear selection should be solid and click in place.
I did put fluid in the converter before putting it in. I don't know if it was exactly a quart, but I did put some in. It did end up coming back out after the last bit I put in, which I'm guessing is from the vent like you said. So I guess the possibility remains that the torque converter isn't seated all the way? Would it be possible for me to unbolt it from the flexplate and spin it in while reaching in? As far as the shifter goes, it's a column shifter. I had my wife go through all the gears, and you can hear an audible click every gear, while I was watching the shift linkage move through the gears.
 

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I did put fluid in the converter before putting it in. I don't know if it was exactly a quart, but I did put some in. It did end up coming back out after the last bit I put in, which I'm guessing is from the vent like you said. So I guess the possibility remains that the torque converter isn't seated all the way? Would it be possible for me to unbolt it from the flexplate and spin it in while reaching in? As far as the shifter goes, it's a column shifter. I had my wife go through all the gears, and you can hear an audible click every gear, while I was watching the shift linkage move through the gears.
I think I was updating my previous post while you were answering - you probably want to refresh and read it. I think you should unbolt the convertor, push it back in and make sure that you only have .125 - .187 clearance - that will ensure that you have a full engagement of the convertor with the pump hub yet allow for flexing so as not to damage the front pump on the transmission. I just delivered a TH350 I built for a 4x4 guy yesterday so I'll be glad to help all I can.
 

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Discussion Starter · #7 ·
I think I was updating my previous post while you were answering - you probably want to refresh and read it. I think you should unbolt the convertor, push it back in and make sure that you only have .125 - .187 clearance - that will ensure that you have a full engagement of the convertor with the pump hub yet allow for flexing so as not to damage the front pump on the transmission. I just delivered a TH350 I built for a 4x4 guy yesterday so I'll be glad to help all I can.
Thanks. Will I be able to put an adequate enough force from beneath the vehicle without unbolting the transmission/engine to seat/reseat the torque converter if it wasn't fully seated in the first place?
 

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You should be able too. Once you have it unbolted, slide it straight back and check that measurement between the mounting tabs and the front edge of the trans bell housing. If you have an inch or bit more, you have it in all the way and can proceed with figuring out the other clearance I gave you. If it doesn't then you're going to have to do the spin and push on it until lines up and falls in - don't pull it forward until you are sure you have it fully engaged, there's usually enough room to pull it too far forward and disengage the splines - which usually lets the convertor angle downward and makes more work for you.
 

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Discussion Starter · #9 ·
You should be able too. Once you have it unbolted, slide it straight back and check that measurement between the mounting tabs and the front edge of the trans bell housing. If you have an inch or bit more, you have it in all the way and can proceed with figuring out the other clearance I gave you. If it doesn't then you're going to have to do the spin and push on it until lines up and falls in - don't pull it forward until you are sure you have it fully engaged, there's usually enough room to pull it too far forward and disengage the splines - which usually lets the convertor angle downward and makes more work for you.
Cool. I'm gonna give it a whirl after work tomorrow. Hopefully that'll do the trick. I'll keep you updated. Thanks for all the help!
 

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I agree with the converter pulling back .360", if that is a confirmed number, you are right around that point that you are pulled out of the pump drive lugs and only driving the pump by the end face of the converter neck pressed up against the face of the pump gear.

If you look at a used converter, you can see the pump drive lugs contact pattern is never anywhere near the full depth of the slot....often barely even 1/2 their depth. It doesn't take a lot to drive a simple hydraulic pump, but go below .125" and you are in problematic territory.

You may have to loosen the trans case from the engine block, depending on how tight a fit the converter nose pilot is into the rear of the crank.

Oil cooler line outlet ports are fine for seeing if you've got pump flow but they don't tell you pressures.....if you don't get anywhere with your converter depth checks showing a problem, then we need to look at getting a trans pressure test gauge on it and find out if you are getting proper pressure directed to each gear by the linkage and valvebody.

If that were to also check out and pressures all show correct, then we have to look at the possibility that your new converter's drive turbine spline bore that connects to the trans input shaft spline may not be right.
 

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Golly, I put 4 or 5 quarts into the converter before installing it.

I always make sure the converter is fully seated in the pump drive and use shop built brackets that fasten from the dirt cover bolts holes to insure the converter cannot slip forward.

I keep the measurements of how deep the converter sets seated in the pump and of the manufacture‘s minimum recommended engagement. Once the tranny is securely bolted to the engine and the cross member, then I measure the distance the converter is from the flex plate. A little math tells me how far it can be moved forward to its minimum engagement. If there is space remaining to butt against the flex plate, I shim the bolts or studs so the converter cannot sit so far forward that engagement with the pump is lost. This is to me is a sensitive assembly that needs careful attention.

The other thing is a functional pressure test, I have all this hooked up before the engine is fired. I’m on these pressures like stink on poop from the gitgo till I feel the setup is tested and complete. For the average guy not doing this all day every day for a living, there are reasonably priced gauges on eBay. Anything less with these trannies is just guess work on an item you have a big financial investment in. Especially with the 700R4 which is not the specific subject here but the point is you know what the pressures are regardless of the transmission and ax with the 700R4 none of this guess work about plucking the TV cable for tightness, though that beats not doing that.

Bogie
 

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I can't say who makes the Jegs brand torque convertors, but I have used one in the past on a Th350 and it ran real well and never had any issues and was really good quality and worked well for what I did. I just got a new one from them to use again and will see here soon how it works. They have so far seem to be decent torque convertors for the average street cruiser.
 

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Discussion Starter · #17 ·
Well.... I was excited, for a second. Did some measuring, it was in fact all the way seated when I unbolted it. This time I added washers to make it about ".130. Started it up, went into gear! Drove it down the street, probably 100-200 yards, lost all gears. What do you guys think?
 

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True Hotrodder
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With the convertor back, what was the measurement from the mounting tab to the flexplate? I use a set of feeler gauges until I have a stack that just slides in then I measure the stack with a micrometer but you can count up the individual gauges too.
 

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Discussion Starter · #19 ·
With the convertor back, what was the measurement from the mounting tab to the flexplate? I use a set of feeler gauges until I have a stack that just slides in then I measure the stack with a micrometer but you can count up the individual gauges too.
It was about .280". I think I miss measured the first time. 2 washers in between, each at about .065. Before that, about 1" from tabs to edge of bellhousing.
 

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.280 - .130 (2x .065) gives you .150 which should be good.

And I have to say that "about this or that" is driving me crazy but that's just me.

Obviously you had it engaged enough to drive the vehicle a few hundred yards and then it appears to have pulled out. I know it's a pain but if you could come up with a different stack of washers that takes up .150 that would still give you the clearance you need at .130 and push the convertor a little bit deeper. I am having a hard time thinking pretty much stock stuff is this far off. You do have the flexplate mounted correctly?
 
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