Hot Rods Torque Converter Won't Completely Seat In Powerglide

I have a Powerglide transmission with a turbo 350 input shaft so a turbo 350 converter can
be used. I have been fighting with this thing for several days trying to get it to seat all the way in.
It's supposed to seat 1 inch back from the bell housing edge to the flex plate mounting pad, but the best I can get it to do is 1/2", and that's not right. I've tried everything I've found on YouTube; centering the pump where it fits in the converter neck, and pushed - wiggled the converter while turning it to no avail, it won't go in any further. Would appreciate suggestions. Thanks, Jim

 

Pump gears in backwards?

 

Don't think so, unless Transmission Specialties put it together wrong.... but anything's possible. If the pump gears were backwards would it go almost all the way in?

 

Yes. The engagement tabs on the driven gear in the pump are "offset" towards the rear of the gear. If it's in backwards the converter won't go all the way in.

 

Pull the input shaft out and see if it’ll go in

 

Depending on the low gear ratio, there are two different length input shafts.

 

Is the converter made for a mid plate motor mount that goes between the engine and trans ?

 

The converter is a stock 350 turbo,

 

Wow! Shows how much I don't know! I've installed a torque converter before in a turbo 400, didn't get it seated in correctly and smoked a rebuilt transmission. Am determined not to make that mistake again, which is why I made this post.

 

Try standing in on the tail shaft and installing it. You can shine a light in the pump to see if the gears are in correctly.

 

If the tabs are installed incorrectly, how do you fix it? Pull the pump cover and flip the pump gear where they are turned the right way? Thanks

 

Yes, exactly. But the pump has to come out, because it's bolted together from the back.

 

Yes, but it take some care so everything is back in proper place.

 

OK, I had a situation happen like this once before, where there were 2 tabs to engage a part; and one was installed correctly, the other wasn't. Is the correct install on the tab where both tabs are thin at the front and thick at the back? I just want to do this right. Thanks

 

I could be wrong, but the 350 input shaft and the Powerglide input shaft are different as I remember. The 350 shaft is pressed into the clutch drum. The Powerglide shaft is a slip fit in the planetary sun gear and has a bushing that slides over it. Are you sure you have a 350 input shaft or do you have an aftermarket shaft that allows you to use a 350 convertor.

If that's what you have, I would probably pull the shaft out and make sure it will fit into the convertor turbine. If it fits, I'd put it back into the transmission and make sure it bottoms in the sun gear. If you look into the pump and verify that the drive tangs on the pump gear are toward the rear, then slide the convertor on, turn and jiggle until it bottoms. If it goes in all the way, you won't be able to get your fingers behind the convertor and the case at the top of the transmission. I watched students fiddle with convertors, try to line up splines and try over and over to bottom the convertor. I never tried to line up anything, just put the convertor on, turn and jiggle, really jiggle. You have 3 thing you have to engage, the input shaft into the turbine, the stator support into the stator, and finally the drive tangs into the pump. The pump is the last thing to engage.

 

Transmission Specialties supplied the input shaft so a turbo 350 converter can be used. It's a 30 spline unit and the torque converter is also 30 spline. I checked the shaft and it does fit the converter and bottoms out in the sun gear. I think the diagnosis from this forum is probably correct -- there's a problem with the drive tangs. I read on the internet that the chamfer on the tangs should be toward the pump housing (pointing back to the back of the trans). I hope that's correct. My plan is to pull the pump tomorrow and see what I have, because I can't tell by looking with the pump installed. I'll let everyone know what I find and what I've done to fix it. Thanks, Jim

 

When you take that pump out it’s better if you make sure the transmission is standing upright so that the direct drum doesn’t come out with it. Also, you will need to separate the pump halves, and they will need to be aligned when you put it back together. you can use a large hose clamp with the O-ring removed from the pump to do that.

 

Subscribed. Do you have a TH350 and a PG TC that you can compare, aka measure up?

 

Here's where we are. Pulled the pump (didn't take it apart) and the tangs are correct. Slid the converter on the pump without the input shaft, and verified that the tangs were correct, the converter bottomed out.
Put the pump back in, put the input shaft back in and the converter won't bottom out.
Took the input shaft out, put the converter back in and it bottoms out.
The input shaft may be too long -- it measures 12 3/4". I thought it was the right one
as it came with the transmission. I've found a few 30 spline powerglide input shafts, but
most don't give the length,, and the ones that do are nearly the same size as what I have. I'm not sure the length is the problem. Unfortunately, I don't have any other transmissions or parts to compare. Thanks, Jim

 

Just saw this video from Hughes Performance and I think this guy has the answer to your problem. Video is 21 minutes long so be patient.

 

Thank you! From what I learned from the video I have a combo shaft that's 12 3/4" long,
and that seems to be the shortest one out there. This all makes me wonder if I have an internal
problem in the transmission, and I think it's time to take the transmission into the repair shop and have it fully checked, rather than get them to seat the converter and have problems later.

Appreciate everyone's responses that tried to help me with this issue. I'll report back on what it took to get it solved. Thanks, Jim

 

Is the place (Transmission Specialties) local to you? If so, that’s where to go.

 

No, they're in Aston, PA -- I'm in Central Texas

 

I see, before taking it in (I’m sure you know) I’d contact them in the morning and get their take on it before taking it up town.
Good luck!

 

I had a similar issue because the torque converter rebuilder installed the stator backwards but I was only about 1/4 inch from being in.

 

If you have any warranty you may want to talk with them first. They probably know what to do about the issue.

 

Do you have a picture of how far that input shaft sticks out past the stator support? If that stator support has a bushing in it or even if it doesn’t, the input shaft, splines should start just p***ed the end of the stator support.

 

There's a washer the tail of the input shaft has to fit through, and that washer will fall and cover the hole so the input can't seat fully. Look in there with the shaft out and see if you can verify if that's the trouble. If so, standing the trans on end and centering the washer with a long screwdriver can work, or turning the output shaft with the trans on the bench can help too. Maybe you've tried this though....

Terry

 

OK, here's what we found. The input shaft wasn't fully seated, that's why the converter wouldn't go all the way in.
It is all the way in now. However, I don't trust the transmission, so the transmission shop is taking it apart and making sure nothing has slipped inside. Better safe than sorry, and the expense is worth it for the peace of mind. Thanks again to every one that responded to my issue. Jim

 

Thanks for letting us know what the issue was. Too many people don't follow up with a conclusion when an issue is resolved.