Torque Converter pad depth below bell housing

Steve Wood

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Does anyone have an actual pad depth below the bell housing mounting surface when the converter is properly seated?

Munroe, in his book, says 0.500" is the depth. Online I have seen people state that it should be more like 0.70-.75".

I am not sure what mine is at the moment but I only have about 0.010" or so clearance at the moment to the flexplate. I used a new flexplate (440source HD) and a new PTC converter.

Prior, in a different car, there was about the usual 1/8" clearance with a different flexplate and a different (same model) PTC converter.

Due to a cracked tail housing mount and the lack of a linkage mounting boss on the case of the current transmission, we decided to install a new transmission. Before we get under the car and install the new set up, I would like to know if I have a problem with the new converter, new flexplate, or did I simply not get the converter all the way in even tho it felt normal on install. It feels like it is engaged. The old transmission is still in the car so I can not do my own measurements on it as of yet.
 

Lefty71

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Well, if you don't know... the clearances you speak of are completely different.... meaning the distance from the flexplate has nothing to do with distance from the bell housing edge. I assume you know this already. I use a homemade jig to keep the converter properly seated in the trans. I use this so I can move stuff around without worry, until time to put the trans in the car. That jig is nothing more than a flat plate that bolts to the bellhousing flange area, AND a 1/2" nut for a spacer... a plain half inch nut is just a smidge over .500 depth. It has never forced a converter back into the trans, there's always still a smidgen of additional play. So, I'd say Monroe is correct, but meaning .500 is a bare minimum. You should really be able to feel this...if you miss the last step, you are gonna be way off that mark. HTH, Lefty71
 

Steve Wood

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Yes, I asked for distance from the face of the bellhousing to the mounting pad on the converter. Munroe says a half inch, but I have seen more than one post that gave numbers closer to 3/4" which I suspect were guesses.

I was curious to see if anyone had actually measured one and I appreciate your guess that it is perhaps slightly over 1/2".

Now, I have seen more than one new converter that was sent out with the incorrect snout dimension and I have heard of, but, not seen that some aftermarket flexplates that were not stamped with the correct offset. Either of these two situations will affect the clearance between the converter and the plate.

I am simply trying to anticipate what the potential problem may be. I have not seen one that that lacked clearance if installed properly and I have not seen one that would install against the flexplate and not press on the pump ears if not installed correctly.

Thanks for your input.
 
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Steve Wood

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Okay, I did not see it in the manual. I guess that wraps it up, then. I appreciate it :)
 

Lefty71

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I was curious to see if anyone had actually measured one and I appreciate your guess that it is perhaps slightly over 1/2".

Be aware that the initial engagement varies somewhat because it depends on the depth of the notch on the converter snout that engages the oil pump drive gears. They're bound to vary somewhat. Two important notes....one, it must push back in far enough to get outta the way as you install the trans and leave a little space to pull out and mate up to the flexplate (as you know). And two, it must not need to pulled out too far to reach the flexplate, as this can also cause big problems. Some people do run into issues, especially with modified engines, midplates, aftermarket crank, flexplate, etc.
 

Dave6T4

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You don't have the torque converter fully engaged. The converter is not back far enough to engage the oil pump drive. You should be able to feel 3 elements engage when installing the converter: 1. input shaft, 2. stator support, 3. oil pump drive. This last engagement can be tricky to complete. A trick I learned was to carefully reach in past the torque converter seal with a long thin screw driver with the converter out, and feel for the oil pump drive lugs. Turn the drive lugs so they are at 12 o'clock and 6 o'clock position. This places the driven inner gear in the centre of the eccentric pump cavity. By installing the converter with the drive tangs in the same position, it should go on easily with a little jiggling. The mounting pads should be somewhere around 5/8" below case flange. Always put some assembly lube or light grease on the converter neck so the front seal is lubricated for initial start. I fabricated a bent retainer that bolts to one of the inspection cover holes, and the other end touches the face of the converter or ring gear to hold it in place when moving the trans around or installing it in car.
 

GTX JOHN

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Sometimes I have had to turn the converter to get it to engage and turn input shaft
on the trans a bit. Easy to screw it up and a real Disaster Deluxe!
 

OKDart

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I had a similar problem with a PTC converter. It felt like the splines weren't meshing well. I got it in far enough to bolt to the flexplate, but there wasn't anymore clearance, and it probably would've eaten the thrust bearing had I run it long enough. It was hard to remove too. I compared it to my old one, and splines looked identical, same count (this was a lock-up converter, so spline count is different from non lock-up).

I called PTC, and they said to send it back (on my dime). When they got it, they called and told me something about the hub was welded wrong (can't remember exactly). They sent it back and it went on nice and smooth.

Here's a pic of a local rebuilt stock torque converter fully installed.

926358-4eda0f41fc8e96522f4c42d899ca9b0d.jpg
 

Steve Wood

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I had a similar problem with a PTC converter. It felt like the splines weren't meshing well. I got it in far enough to bolt to the flexplate, but there wasn't anymore clearance, and it probably would've eaten the thrust bearing had I run it long enough. It was hard to remove too. I compared it to my old one, and splines looked identical, same count (this was a lock-up converter, so spline count is different from non lock-up).

I called PTC, and they said to send it back (on my dime). When they got it, they called and told me something about the hub was welded wrong (can't remember exactly). They sent it back and it went on nice and smooth.

Here's a pic of a local rebuilt stock torque converter fully installed.

View attachment 1188871

This is my main fear. You have described exactly what I have encountered. thanks for the comment :)
 

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