Hot Rods AD_NAPCO's 39 GMC Rocket 324 Build

Are you sure that the/some of needles are getting past the tube? It's a steam bath here and thinking is not doing well tonight..

Ok, Found some tubes that will fit in the bore, there are two types on my bench now. First type is very thick tube about 1/8" wall and has an unwelded seam lengthwise. Those vary at 5.080 tp 5.085

then I have a single one very thin, welded seam, about .036 wall, and it is 4.955

But I need to bring up the differences in cluter BORES.. I don't know if I covered that before anywhere on hamb. Go look at my pic of two clusters; see that one needle is sticking out? where I hung the smallest washer? Ok, that is as far as the last needle will go in...it's too tight. I never found needles here to fit correctly with no gaps or no bind.

So..I knew the bores were different, so I just measured the REAR bore only, on BOTH:
one is 1.225
other 1.180

Why I bring this up; is there a chance you bought new needles and are the wrong "needle" diameter?? Is that what is hitting? when you try to slide the solid pin in??

Fit it up on the bench, without the trans case. Or load both ends with needles, then try the shaft a bit on each end to see if the shaft can fit?
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I will do that Frank. In the meantime, the spacer tube I have is the welded seam type, with the .036 wall, and the same 4.955 length. I will measure my original rollers vs. my new ones and see if there is a difference, and as you said, bench test the rollers and shaft.

 

I have the internals from a 55-56 Pontiac tranny that I trashed a while ago. The spacer is 4.964 in length, .029 thick and has an OD of 1.025. The needles measure out at .125 and the main shaft measures out at .935. I have never used the hose trick but always a piece of conduit. Never had any issues loading one so I am at a loss here to suggest what is going on if all the measurements compare relatively. Have you tried standing the case on end to help alleviate the cluster trying to drop while shoving the shaft in?

 

I thought about that just as I was cleaning up last night. I will give it a shot tonight. I did load the cluster on the bench with shaft just to test everything out Seems like everything fits as it should. I'm not sure what my binding issue was but I'll attack it from a different angle tonight. I already was able to determine that I had room for another bronze washer in the stack. I wonder just how much end play was in this cluster to start with. I have the feeling it was a lot. Walt, you had said the end play should be '12-25' I'm guessing you meant thousandths, right? As in .012-.025?

 

Yes,, got that spec from 'ol John at NW but knowing how he gets "confused" at times perhaps you should check with him to requalify that specification just to be absolute!

 

Finally got the cluster loaded. Jeez. So, a couple things were fighting me. Mainly I think that the thin wall bearing spacer has a tendency to fall in the cluster bore when horizontal and it actually does create enough space for rollers to slip past and wedge between the bore and the spacer. The last time I experienced this and was able to completely verify it was happening, I was using a piece of 1/2" od pipe I cut to length this morning instead of the heater hose. I decided to do that just to absolutely eliminate the possibility of any curve in the hose fouling me up. Well, it worked better, but still not quite right because the OD of the pipe is not enough to hold the spacer at a stable centerline with the rollers for the shaft to slip through. So my last, and successful attempt involved using some red axle grease, which is quite a bit thicker than the white lithium grease i was using before, to hold all the needles in place without a loading blank in place. I then used the axle grease in a thin coat to stick washers to the end of the cluster, and the case, and was able to slip the shaft to just get into the first set of rollers. I then really carefully tipped the whole mess on end, and still had to wiggle the shaft a bit to get the spacer to line up, but it finally did and I got the dang thing to slide home.

So front to back, my current rear stack looks like this: Steel, Bronze, Bronze, Steel, Bronze. With this combination, I currently have .020" end play. I hope that's within spec. Ron from Northwest Transmissions is looking it up for me now. It must have been sloppy as hell before so this has to be an improvement no matter what.

 

Just for the heck of it, I decided to see if the reverse idler would go in with the cluster in place, and luckily it goes in easily. So, Frank, if you think the .020" end play is acceptable on that cluster gear I'm gonna call this part of the process done and set about getting the rest of it put back together again. I still haven't heard from NW trans yet.

 

Well I don't have any thin shims with correct ID/OD to get it tighter..so go with the 20. Closest I had was .030
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Great! Moving on then!

 

Well I was able to sneak out a little at a time today and get the main case back together again. I had to reuse the snap ring that fits down inside second gear. The one provided was way too stout. There was no way I was going to get it onto the shaft. All good though. Everything seems to be right! So next time I have a little time I'll be mounting up the tail housing. Do you guys use any gasket sealer on the paper gaskets or just go paper to metal and call it good? So far all the gaskets that came from this showed no signs of Permatex type stuff.

 

Since the tail housing may get replaced before the build is done, dry is Ok, but look closely at the modified oil hole....it might be wise to use RTV at that spot, if it looks less than smooth.

 

Reading thru the info Paul posted from the installation manual I noticed that they state not to reuse the set screws in the shifter yokes as they are deformed at the slotted end to provide a self locking feature which is lost when you reuse them.......also to be torqued to 15-20 lbs. I noticed that it appears all the ones I have taken out have already been reused. Wonder if any new ones are around or what do you other guys think about this subject?
Ordered a new spring for the shifter tower from Century. Will be here next week and I will let you know what it looks like. How is your machinist guy doing on the tranny Josh?

 

I just got back into town. I was gone for a few days, and really busy with work before that. I did get the top cover back with the broken ear repaired. Looks decent, and feels strong. He also machined some bolts to replace the staked over pins that retain the shifter plate. Rather than tapping the cover, he clearanced it for some nuts to retain the bolts/pins. He also case hardened the bolts. I'll post pics soon.

 

any updates Josh?
I am up in Canada until the 20th so I do not know if my spring has shown up yet from Century Spring since my mail is being held. Hope it is there when I get home.

 

I have been insanely busy and had to put the trans on hold for a while finally got back out there yesterday and got the case degreased, etch primed and painted. This morning I'm putting it all together on the engine stand. I got the bell housing bolted up and mounted the trans to it. For some reason upon first assembly the trans was locked up. Not sure what I did to cause that but I have now taken it back off the stand and confirmed that everything seems to be working properly. My bell was thin, so the machinist had to bore the relief hole all the way through, and then bored again on the inside to accept a 1" freeze plug for a cap. He said he cut it close enough that he had to press the freeze plug in so it should be good and tight. Still I will probably put a bead of epoxy around the edge for extra insurance. I confirmed that I got the right spot just now as I was able to slide the shift rail all the way home with the bell in place. Now I just have to figure out why the trans is locked up when I get it mounted. For the time being I'm not going to reinstall the shifter, as I still have to modify it (a) because the PO made an ugly mess of the stock one, and (b) because I'm not sure yet where the trans will land under the truck. I'll post progress pics this afternoon including the modified shifter plate retainer bolts the machinest made up.

 

So I've been out there fiddling with the trans/bell trying to get the gears to spin freely with the bell bolted up. So far no joy. I shot a couple videos so you can see what's going on. Maybe one of you guys will see what I'm not. Seems that as soon as I get the bell bolts snugged down, the trans goes into full lock... If I back them off just a couple turns, it unlocks. I'm not sure what could be binding. The bearing retainer fits down into the bell fine, and it's the same diameter as the bearing, so that should be fine. The bearing snapring is smaller than the relief for it in the bell so I would think that would float given the extra few thousandths of gasket added to the mix...

Here are a couple videos, first one shows lockup, second no lockup. I'd appreciate any help with this.





Here's the new threaded retainer pin. He just happened to have a bucket of these 1/4-28 bolts with these big shoulders on them already. He machined them to match the original pins and then ground flats on them so they can be grabbed with a wrench.



He also clearanced the top cover for a nut.



Here's the underside. He case hardened the retaining surfaces.

 

I watched the first vid quite a few times. When you rattle it, that is exactly what it would sound like when the trans is in two gears at once. It looks like the input shaft is still OK, not bound up or locked up.

One thing I can't see, is if one of the syncro rings is "sticking" to either the input shaft taper or 2nd gear taper. If one is stuck, that would be like it was in "one" gear....and then if the 1/R sliding gear is just barely engaged, then it would sound like it's in two gears...

Over the net is tough to see or feel, the same as in person...

You are also fighting the 1/R shift rod floating backwards; clamp or weight that detent spring down.

Then I'd leave the bell loose, and try each gear, enough to move the output at least one turn. I'd be checking to see for sure, if the 1/R rod will clear the freeze plug, ....I'm grabbing at straws to come up with why you have problems just by tightening the trans bolts.

 

2nd look after thinking more....

common sense suggests that when you tighten the trans bolts, the OD of the input main bearing is pushing back?

Tried to compare both vids to see if the input bearing looks like it is moved forward with trans loose; possibly. But the 3rd gear syncro ring seems looser with trans loose?

When you had the trans off the bell, did the front main bearing outer large snap ring sit tight against the trans case face? If not, I wonder if one of the short fat needles is sitting in the bore of the input shaft pocket? I don't know if one needle can get knocked loose and still fit sideways in the back of the bore, which would likely push the case main bearing forward a bit. You would think the outer snap ring would not fit against the case face.

 

Thanks for responding and taking the time to help Frank. I was thinking that the front bearing snap ring wasn't seating hard up against the face of the case like it should. Maybe there is an issue there. I'll get out there tomorrow again and go through it more thoroughly. Now, for my next potential bonehead move... While cleaning up I found a washer/shim that I'm not sure if I left out on purpose or not... I don't remember if a new one came with the rebuild parts or not, and I don't remember exactly where it went! This is the problem with getting pulled away from these projects. I end up forgetting some of these details. So... Do you recognize this washer/shim?

 

I sometimes have visual perception problems with pics.....this one, I can't guess the diameter

at first glance I thought it was a shield that came out of a sealed main case bearing. If the size is way smaller than that, I'd say it was a substitute shim when they "fixed" the cluster wear?

 

I'm sorry Frank... I should have thought of that. 1 11/16" OD x 1 3/8" ID x 1/16" thick. Seems like an input or output shaft item, possibly.

 

I wrote those down and will look through my stuff in the morning.
Walt had one apart very recently, so maybe he will see this

 

I looked in the parts book view, and as far as the upper shafts, the only possibility would be the washer behind the small snapring on the front of the input shaft. Take a look after you remove the candlestick, it will be plain to see if it is missing from there.

I can measure an input shaft in the morning, to see if it matches the 1-3/8" at the snapring surface of the shaft. Should also match the ID of your old front main case bearing, if that is what it is.

 

I measured an input and that washer matches it, so that is where it came from.

the bearing goes on the input first, then that washer, and then the snapring

 

Thanks Frank.

I checked and it looks like that washer is already behind the snapring, so they must have sent me one and I just didn't remember. I guess it'd be good in the future to mark the old and new as I go when I do this kind of thing. Lots to learn...

So anyway I went ahead and installed the shifter in the top cover and tried to use it to go through all the gears. Something's not right because I can't get it to easily shift into first or reverse, and when I do, it won't turn. seems to find 2nd and 3rd ok, but then again, I can't seem to find neutral... So, I took the cover off and started looking really closely at the shift rails, especially on the 2nd/3rd side. It seems the neutral position on the 2nd/3rd shift rail is not lining up with the hole, and the detent ball is not seating. So I'm wondering now if my synchro assembly is somehow not indexed correctly? I can't see it being any other adjustment than that because it can only go in one direction. I recall you posting in another thread to make sure that you don't get it in backwards. On mine, the main drive gear is considerably smaller than 2nd gear so the synchro has a big end and a little end. Only goes one direction... So is it possible that in needs indexing? That doesn't even seem like it could cause the problem I'm having. I'll post a couple more videos in a little bit.

 

Explain that in the video w/a good view.

With both shift rails in their central detent, then the notches on the two parts where the shifter tail fits into, should be directly across from each other. If that's not lining up, and if you suspect it is a problem with 2/3, then see if 2 or 3 syncro ring is crowded into it's mating gear taper. Why it would be, is not clear to me.

With the two rails in the central detents, I can't see how the two notches for the shifter tail would not be perfectly aligned.

any views with a steady camera will help

 

Josh, Frank....I have been up in Canada and was out of touch completely with limited internet service. Tonight I am in Bangor so have access again. Won't be in the garage now till next Saturday so I am not going to be much help.
??? on the synchro being two different sizes on each end taper. I thought all selector trannies had the same size front and back. The rear is machined a bit differently which is easily seen when you look at it and I think this goes to the rear.
So Josh do you remember the tranny shifting and working before tear down? Bolted to the bell ? Seems I recall that the bell was not drilled for the rail so could it have been bolted up?
Make up a couple of steel flat fingers and bolt them to the tranny and across the springs to get the pressure back on the balls for the rail. Then you can see what is going on a little better. It sure sounds like it is stuck between gears in the video?????????????????/

 

Walt, I never did try to bolt the trans to the bell before this tear down started. I seem to remember the trans shifting just fine before I tore into it. I think I have two problems. One, as yet unidentified. The one I think I have spotted has to do with the fact that there is zero room for endplay on the candlestick/bearing stack inside the bellhousing once it's bolted in. In fact it's short of room enough that the bell is compressing the input shaft into the synchro tapers forcing a permanent grabbing action, thereby eliminating the possiblity of any neutral action. Here are some measurements. Maybe you could compare what you have.

From the face of the bell to the surface where the candlestick flange sits is .446". From the face of the trans to the front surface of the candlestick ( I'm calling this the bearing/retainer stack) is .483" This is without forcing any back pressure on the bearing. So the snap ring is not hard up against the face. There is a .043" gap between the snap ring and the face of the trans. The thickness of the candlestick flange is .283". The diameter is 2.833" and the recess in the bell is 2.835"
So I think I need clearance for end play. The second problem has to do with not being able to spin the trans in first/reverse even off the bell. Not sure what is going on there. I'll post videos soon.

 

The front bearing snap ring, should be able to sit against the case and stay there, without any pressure from the candlestick pushing on the bearing or ring.

need to find out why it won't.

 

Here's a long video from this afternoon. I have been outside for a while trying to figure out what's going on. Will probably have another one soon including showing what the gap looks like between the front bearing snapring and teh case.