Hot Rods AD_NAPCO's 39 GMC Rocket 324 Build

could it be possible the needle bearings are a little too long? i remember putting a tranny together years ago [not an olds, and i can not remember what it was] and i put one wrong needle in that was a little longer.

 

It's too late for me to go to the shop to look at a second gear...

Guys; take a look a 1:30 in the video. Does it look like the thick 2nd gear thrust washer that is supposed to be in front of 2nd gear, is on the back of 2nd gear? It looks like it is to me.

Ok, if that is true, that would crowd the syncro, and also cause shift rail misalignment, as well as pushing the case bearings outwards.

what do you see on the back of 2nd?

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I've eaten crow before..... but I am 100% convinced the washer is there, BEHIND 2nd gear.

2nd gear sits against the "stepped-up"face of the larger OD spiral section for the 1/R slider. The ID bore of 2nd gear is much smaller than the OD of the spiral section. So, 2nd gear sits against that step-up of the spiral section you see in the vid. It has no washer there when new. The machined washer fits in a recess in the FRONT of 2nd gear, then there is that snapring with the wire spacer ring under the snapring.

this would explain all the multiple issues. Move the washer, and have a beer

 

I found a pic I put on the Fedcospeed thread, showing the thrust washer and snapring that goes in front of 2nd gear. Note the internal tang on the ID of the washer. That tang is a must-have, to keep the washer locked to the shaft, so it can't wear the snap ring out.

When you put 2nd gear back on, then look in the step bore, you will see two opposing grooves for the tang. However only one of those grooves is deep enough for that tang to slide on. The opposite groove is actually the oil groove for 2nd gear, which musn't be blocked, so that is why GM made the tang groove deeper...so a mistake could not be made on blocking the oil path
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Wow Frank... I just came inside and saw your post. My wife will crucify me if I got back out to the shop now to double check this now. So I'll wait til morning. If I did get that backwards I'll be amazed. I am still trying to figure out how what you're suggesting is even possible... Anyway, I had convinced myself that there is an extra washer that was placed between the rear bearing and the shoulder of the sliding gear portion of the output shaft. You'll see in my next epic video what I'm talking about. If that washer is supposed to be there then you are probably right... Thanks for all the help on this. Amazingly, I did have the presence of mind to compare all the needle bearings I got from the supplier and they were identical to what was in there to begin with.

 

The front shaft will move in/out like yours does if the interference fit of the bearing and the case allows it. Some are tighter, some loose from my experience.
The rear snap ring needs to be against the case so if it is binding with it against the case there is a definite fit issue. I am not going to be able to help you much until I get home where I can look at mine. I am going to look at the video again.

I do not recall seeing that spacer on the rear bearing on my shaft. Think that would be the culprit. See what Frank says.

 

here is a blow up of a Pontiac selector tranny..................no spacer!

 

^ Correct, there should not be a spacer in front of the rear main bearing.

Just a guess on why it is there; if someone added one before, the guy that pressed the new bearing on, would definitely put it back on....unless he had a manual on Olds transmissions.

Josh, what I would try for now: -Put the thrust washer in front of 2nd gear...and you could leave that difficult snapring off for now. Then put the trans together to see if the rail detents line up and if the syncro operates. ===There may be some reason why they moved the mainshaft forward to possibly tighten the clearances in the syncro area?

It would suck to get the bearing pressed off to remove the washer/spacer, then find out something is still not right.

 

I should think before posting...

Guys, I think that "added" spacer came with the new repro bearing?? I bet the new bearing is not as wide as the original bearing part number. Think about the fact that there is a rear snapring BEHIND that bearing...that ring groove would be hidden under the bearing if some spacer was added by mistake.

Right?

I say leave that spacer there, then move the 2nd gear thrust back up front, and I bet it will be all good.
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Thanks guys... I'm headed out to the garage now to see what's what with this thing. Will report back soon.

 

Josh, I bet you still have that old rear bearing. Measure the width of old vs. new. I am positive the new one is not as wide. The spacer would have come with the new retrofit bearing with instructions on where to put the new spacer/shim.

If so, the press guy did put it in the correct spot, which would keep the mainshaft location exactly as it was. If the press guy put it on the backside, that would have moved the mainshaft rearwards. I am confident the spacer is needed, and is in the correct location.

Move the 2nd gear thrust washer back to being in front of 2nd gear. It should fix every issue IMO
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Frank I didn't see your post about comparing the old and new bearings. You were right. The thrust washer was behind the gear. Dumbass award nominee right here. Anyway, I got that pain in the ass snap ring out, moved the washer to the front side, and put the gears back in without the snap ring like you suggested. Both bearings fit nice and snug against the case with no effort and everything spun nice and smooth. So I put the snap ring in and reassembled it all on the stand and sure enough with all the gaskets, bolted up to the bell it all moves freely. I have to, once again, thank you Frank, and Walt for being so ready and willing to help me with this. I'm really grateful for the both of you. I wish I lived closer so I could take you guys out for some frosty brews! I'll make it up somehow.

 

great news Josh. Just got home (rain chased us out of Can). I had not realized that you replaced that rear bearing with a new one. Good call Frank on the spacer. Glad this is behind you now.

 

Found this thread by searching casting number.

I have an Olds tail housing I am not using, casting #1173968-3. Does anyone need it?

 

need pics of the big end to see if the thrust plate is broken and the overall length

 

@Skankin' Rat Fink I would be interested if it doesn't have the broken thrust surface that mine has, and like Walt says, need the overall length. I can't remember my casting number off the top of my head.

 

can't remember seeing one with a pipe plug hole in the tail like that......now I am curious!

 

Later this week when I'm in the shop I will get you a length measurement. I haven't looked it over very closely for cracks yet, so I'll do that as well. I will post better pictures below.

That hole looks to be for the vent on top.

 

yep, for the vent! Looked a lot bigger to me in the first smaller pic. Both of those look to be good in the thrust plate area.