71OldsCut

Good point! I will do the pump cleaning and rebuilding first.

RetroRanger

good thread 71 oldscut im following along

cherokeepeople

if i need to do this i go late at night.the car washes around here usually only have somebody around til about 5 or so.go in at 9 at night there is nobody around.

71OldsCut

I should be doing the air pressure test some time tomorrow. What is a good PSI to do it with? I have read anywhere from 10PSI up to 30PSI. The last thing I want to do is put too much through there and damage something, assuming that is even possible.

I have never run the compressor at PSI that low, hopefully it will shut off and not keep running. It will be hard to listen for leaks if the compressor is screaming away right beside me.

bry593

matt69olds

droldsmorland

Enough to force the clutch pack against the snap ring.
You should see the stack compress and release when you let the air out. It has to maintain air psi. You shouldn't hear bypass leakage.

The gap is set dry. Now a question I've not been able to answer.... Adding or dipping the frictions/steels in ATF to do final install(an absolute must do) effects that stack up tolerance. Thus you do need to stick with gap spec for that pack. But is it better to be a couple thou tight or loose???

If you can't achieve the correct dry spec you have the wrong thickness frictions and or steels. I ran into this with a Rev break TH7004R. Some time in late 86 early 87 they redesigned things and installed an aux valve body etc... The kit I bought didnt cover the new rev. I found it right away when the stack up tolerance was way too large. Took the drum to a friendly trans shop. The owner allowed me to go in the back and speak with one of the techs. He did the air(first time I witnesed that) test and knew immediately what was wrong. He said this must be an early 87 out of a V6 S10. Yep...He took out the stack. went into the parts room and came out with the correct stack. installed it for me air tested and had the correct gap. He said Ill keep the short stack and trad you for this...Free of charge! Great lesson learned the easy way for once.

71OldsCut

Hi guys, I am subscribed to the thread but it didn't tell me about the last couple replies.

So for the air pressure test, the spring loaded piece on the pump comes up and down with no noticeable leakage. The clutch that goes right on the pump engages solidly, but I hear air pressure leaking a bit, then the last piece that sits right on top wasn't engaging at all at roughly 30 PSI. I tried 75 PSI and it does engage, but there is air leakage.

I did take the first clutch assembly that sits on the pump back apart, made sure the seals were not damaged and put it back together being very careful. The seals seem fairly strong in terms of the force it takes to lift the lip the wrong way. That and also there isn't a lot of clearance once it is in there. I would assume that if a lip was curled up or pinched it would be very hard to rotate the part and it would have to be forced into place fairly hard.

I did notice that the majority of the air leaking out when testing the top clutch assembly is coming from that hole that is about 3/8" inward from where the snap ring sits. There is also a bit coming out of one of the other holes in the pump a little ways down from the hole I am blowing the air into.

Does any of that raise any red flags to anyone, or should I just take it all back apart again and try again?

matt69olds

71OldsCut

That is good to know. I will try to put some vaseline on the ring seals and see how that goes. One thing I forgot is that ring style bearing with the single tank that goes on right at the underside of the pump. That helped a bit, and pushing down on the top of it helped too, but I don't think that is a proper way to do the test.

I can't plug my phone in to take a picture of the hole that most of the air seems to be coming from, but found a picture online that shows it. It is not the one in the center of the shaft, but a little bit inward of where the snap ring goes.

matt69olds

71OldsCut

The vaseline on those lock rings on the pump seemed to help a little. I just finished taking the two pieces back apart, took the seals off to make sure there were no tears or signs of them being folded over. Everything looked great. I actually tried using some playing cards to get them back in. It worked pretty well. I am confident that they are all seated properly.

I don't want to take the "screw it, good enough" approach here, but it could also just be that I have never seen this test done before and am not seeing/hearing what I was expecting, but things are actually good. I did actually pull up a youtube video and it looks and sounds about like mine. I am probably just concerned with nothing here. The clutch pack closest to the pump engages hard with a loud thud. The other engages weaker, but if I put a finger over the hole on top or the other hole that air is coming out of on the pump it engages hard too.

71OldsCut

So regarding input shaft endplay, The book says 0.015-0.030, but I have found online 0.017 to 0.044 for units newer than 1977 and 0.032 to 0.064 for older units. am sure that tighter is better, but for a stock daily driver when the weather is nice, how critical is it to get this number down? Mine is at about 0.040.

matt69olds

This is a situation where tighter clearances are better. Things will loosen up as they wear. If you have the thickest thrust washer on the pump and enf play is still excessive, there are “problem solver” thicker thrust washers that go under the annulus gear that goes inside the direct drum. From what I have read on other forums the 10 bolt rear-end pinion shims are also pretty close to being the right size. You don’t want to stack too many shims under the pump thrust washer, you could run into issues with the sealing rings on the pump being blocked or uncovered. Use the thickest thrust washer, if clearance is still excessive then you need to take dome out somewhere else. Hang in there, you will get this whipped!!

71OldsCut

I will have to try a local shop to see if they have any shims. The rebuild kit seems to have everything except those. I just noticed that it actually has two sets of valve body gaskets too, one set has transtec printed on them. I suppose those would be for the shift kit and the blank ones would be stock?

Is it OK, to proceed with the rest of the build in terms of getting the valve body back on and all the other pieces? I won't be able to get shims until Monday at the earliest. I don't see why I wouldn't be able to pull the pump back out with that stuff reinstalled. Hopefully pulling it back out won't hurt the gasket...

matt69olds

71OldsCut

That makes sense. I will get this finished up today and hope that one of the local places has a few shims they are willing to sell me. My inexperienced opinion from what I have read online is that for my purposes the endplay is acceptable, but tighter would be better. If I can get these shims I would for sure prefer to have them in and tighten things up. I think I will be greedy and ask if they happen to have a space pump gasket too just in case the one I have in there gets damaged when I pull the pump out again.

Good point with the guide pins for the valve body. If I recall I used 5/16" guide pins for the pump so I will see if these fit.

71OldsCut

I think I am done other than trying some shims to decrease the input shaft endplay. How big of a concern is it to add too many shims and get the oil pump holes in a bad spot?

Other than that, I am very pleased with how it went. The last pressure test once everything was in the case went well, once I figured out how to plug things up to where air wasn't just coming out all over the place. Both clutch packs seemed to engage strongly as did the low/reverse. I am very glad to have those seals come out in pieces like they did so that I know I found the problem.

A very big thank you to everyone along the way that gave me the confidence to take this on and all the help along the way to help get this done. I will post some pictures of the compressor tool I made and maybe a quick list of things that had I known going in to this would have made things a little easier and less stressful in case someone down the road is looking to the the same thing and comes across this thread.

matt69olds

bry593

71OldsCut

I just tried one and they said they don't have any. I will try a few more. Like matt69olds says, if it is in spec, I won't lose any sleep over it if I can't find any.

I am excited to get this thing back on and see how it works. I am not looking forward to fighting with the cooler lines. The old fittings were so corroded in place I had to cut them off. I have new lines that will require a little bit of adjustment to make work, but hopefully I can get them all tightened up and run properly. One of the fittings at the radiator was all rounded off too so it will be nice to replace them with new. Whoever worked on the car before apparently didn't know about the proper wrenches for line fittings. The fuel line to the carb is rounded off too with vice grip marks on it....

bry593

71OldsCut

I will have to check where I got the lines from, but Right Stuff sounds familiar. They look right but a lot of the reviews said they didn't fit exactly and required some re-bending. That part should be easy enough, it is just getting them tight with the very limited space to turn wrenches that I am not looking forward to. I might try to get them on and at least started with the trans lowered a bit to get some more room.

I will have to also remember to get the new driver's side header on first. It is wide open right now and should be a lot easier than doing it with the transmission and starter back on.

droldsmorland

Inline tube is another good source for pre-bent lines.

bry593

I'm pretty loyal to Right Stuff Detailing at getdiscbrakes.com. They have made custom lines for me and also supplied lines free of charge when the kit didn't quite cover my application. You can call them up and talk to a real person that knows real stuff about cars! Not to mention, the lines are normally just about spot on and are made just like the originals and for a very attractive price. With that sort of service and quality, I can't justify going anywhere else.

Inline

My tips as first-timer to other first-timers.

Get RIGHT TOOLS for bushing install. I tried a hack-way, and managed to destroy few bushings. Then i made an ghetto-lathe and made correct bushing tools from oversize metric bearing tools.

Also, mostly in case you dont happen to live in US / Canada, get two sets of bushings, and those pesky lip-seals to drums. Waiting for a new set of bushings blows, also the moment you pressurise drum and notice it leaks, and wait week for new seals, or buy whole gasket-set for 80$.

Otherwise TH350 turned out to be pretty simple, and your able to do it with regular tools you have at home. And get a ton of brake-cleaner.

71OldsCut

LOL, I agree completely with the right tools for bushing and spare bushing if you can get them. The only bushing I had that went wrong was on the clutch pack that has the splined shaft. There was the bushing that can be removed with a tap, which worked great... for the original one. The new one I was putting in ended up splitting at the seam which I didn't realise until it was more than half in, so it was further in on one side than the other. Sockets don't work like proper drivers, lol. I was able to straighten it out and get it in and it even looked nice, but my compulsive behaviour wasn't letting me rest easy about it. I had to pick my torque converter up from a shop that cut it open and checked it out, so while I was there I asked if they happen to have a spare bushing. To my surprise they did and gave it to me for free.

The problem came in trying to get the new one back out. The book says to use small amounts of red threadlocker on the bushings. The new one was not coming out with a tap, so I had to resort to using punches to make a lip that I could collapse the bushing and pry it out - not fun. Long story short, I think having the right set of drivers would have prevented this from happening in the first place, but if it does, do yourself a favour and take the questionable bushing out before the threadlocker dries....

Also very much agree with the brake cleaner..... and rags or cloths. Wiping parts with paper towels tends to leave bits behind...

I still have to get some pictures of the compressor tool as well as what I did with the cards as a lip seal in case anyone finds that easier. I think both ways are a bit of a pain, but I found with the cards I was much more confident that the lips were down and nothing was pinched. I think there is a lot of valuable info in this thread and it will likely be very useful to others that are on the fence about doing this. I certainly would not hesitate to do another one now.

Inline

Ouch.. One thing occured to me when i was just discussing about transmissions with my friend.

Between first time when i tried installing bushings with hack-tools and broke them, and getting new bushings and making correct tools, i just realised that at try #2 i totally forgot bearing retention glue, ie. Loctite….. The bushings were really tight to cases and axles, and by thinking they shouldnt move anywhere nor turn..
Am i screwed now or…?

71OldsCut

Hmmm, I think that would be a question for people who have done a lot more maybe with and without and what they experienced. I just followed the book which said to do it. I thought it was overkill, especially using the red stuff, but I figured the author's decades of experience versus my zero experience I had better just do what he says. Hopefully it will be fine.....

Inline

Thats why im asking, since this is my first trans too. Just to think, thought i didnt see any residues of locking compound either on bushing surfaces.. If my memory serves me.

bry593

The factory bushing was not loctited. So long as the interference fit is tight, you should be fine.

Inline

Thank you.

Inline

While we are here with TH350's, might we add some theoretical talk about the amount of frictions.

I had 5/5/4/3 from factory, and updated, because might as well, to 5/5/5/3. But, assuming you use shift-kit, i used transgo 1-2, which comes with new valve-body support plate, i assume this dual feeds direct, is the 5th friction in reality even necessary on street car?

As said, i did just because, but does anyone have some thoughts what 4-friction with dual-feed take compared to 5 frictions?

bry593

Assuming same pressure, 5/4=25% greater torque capacity.

matt69olds

The factory didn’t loctire the bushings, if the bushings take some effort to drive them in, and it doesn’t take excessive amount of effort to turn the parts, you should be good. It’s not uncommon to have to polish the bushings to get a good fit.

I have on occasion filed smal dips into the pump bushing bore and staked the bushing in place. Sometimes the pump bushing just doesn’t all that great after multiple bushing replacements. I think staking the bushing is much more reliable than loctite.


Unless its a completly stock rebuild, and you know without a doubt that no engine performance upgrades are in the future, do the dual feed modifications and machine the piston for the 5th friction. No downside to either modification. I have asked countless people with far more transmission knowledge than I’ll ever have why Hydromative bothered with the added complexity and hydraulics of the dual chamber in the direct deum. The 400, 350, 2004R trans all have it, all of them are easily defeated with a seal removal, and blocking one hole. To the best of my knowledge, no other transmission company does the dual function clutch.

Inline

Thanks for some insight. About bushings, yes, i had to hit few with fine brake-cylinder hone after measuring they were for sure straight on the bore. Took very few turns to get them going.

Reason i asked about 5th friction and how necessary is it; is that many times we do ( been quilty many times) something out of habit without even questioning the need for that modification/ part we just bought. Rather we did it just because masses keeps repeating the same "old truth" without even stopping for a minute to ask themselves "why"?

I did add Transgo 1-2 shiftkit, hardened intermediate sprag, new roller clutches to intermediate and low/reverse, wider direct-drum bushing, 4 sun-gear bushings and while there i opened the existing holes of direct-drum drive-hubs to 7.5mm ( .310" suggested by book turns out to something like 7.8mm). As a "bonus" i also have HD-band, it just came on the kit. I quess im fine with my 350 Olds.

Core was also good, since it was original behind smog 350-engine from 76', not much power to rip it apart or even think of playing with it. Case had no wear and no slipped frictions, no warped parts, end-play really nice as were the oil-pump gears.

One "trick" i did was with that smallest, input shaft bushing which is hard to get out. Metric M14-bolt with collars, it threads to that soft bronze ( if you happen to have bronze-bushing instead of nylon), and just turning it clockwise lifts it out up to bolt-head.

matt69olds

The input bushing is a PITA to remove. Drill it, tap it, chisel, punch, easy out, whatever it takes. When I worked at Coan Engineering that was one of my many jobs, the Powerglide used the same bushing in the carriers. I bet I removed about 100 a week. Once all the pinion gears are removed there is a little more room to work with that bushing, I had a pilot bushing removal tool that usually worked to get them out. If not, I had to get creative to remove them.

Inline

While topic is still "hot".

Speaking of various shiftkits. Those with dual-feed add-on plates.
Im speaking of Transgo reprogramming kit for TH350 to be exact.
I remember when i torn one separator plate gasket, and checked it against stock separator plate gasket; all the holes were there. This led me to discover stock vs Transgo separator plate. All the holes were there, but Transgo had sized some of them differently. Plus the dual-feed add-on plate.

Ever since ive been wondering following. Since all the passages are there, just sized differently, plus transgo separator plate is alot beefier than stock ( mine showed crossleaking on few spots). What about using Transgo separator plate, but removing that dual feed add-on plate, and dual feed it internally? Its only tack-welded on two spots, and for me it looked kinda questionable for long term use, mainly about the possibility of huge leak if the fluid seeks path of least resistance between plates.

What i think about it:
- One less place to leak if dual-feeding internally
- You still retain the improvements Transgo made, by retaining the hard-parts going to valve-body, plus the sizing of the orifices and passages and beefier separator plate. Trans builders seems to rate Transgo reprogramming kit very high
- Of course improvemt is relative term, GM did no bad job of making great feeling actuation of gears. Many modern automatics could take a lesson or two..
- No non-reversible mods done to your case like drilling holes bigger; all is on separator plate and as hard parts on valve body, you just need to remove plug from low/reverse passage if internally dual-fed, so for any reason you can still reverse everything back to as GM made it

Any thoughts? Or am i missing something?

droldsmorland

More info than you want or need:
Discussion about the term "Improves High Gear Oiling" and Info about "Dual Feeding":

"improves high gear oiling" is a vague term...

If I drill the 3rd feed hole (more fluid volume in a shorter period of time) to apply the piston quicker, you have a firmer shift and "improved high gear oiling".
If I use a stiffer pressure regulator spring, and therefore more line pressure at all times, I have "improved" oiling to all circuits.

However, neither of these mods (while common in all shift kits) has "dual fed" the direct drum.

There are two ways to dual feed:
The one that all trans brake (TH400 and TH350) setups use, and I use on TH350's is to leave the center seal off the direct apply piston, sometimes a ring off the center support (TH400) or stator (TH350), and plug a passage in the separator plate or transmission case.

The other method is to "make" an additional passage. ON ALL TH350 kits they accomplish this by using a "transfer plate" that is sandwiched between the support plate in front of the valve body.
This plate has a slot cut out, and when sandwiched between the support plate and the separator plate is simply a new passageway for the fluid to flow to "the other side" of the direct apply piston.

The direct piston in a TH350 and 400 has two purposes.
One is that it applies in direct or 3rd gear.
The other is it must also apply in reverse.

Without going into a huge long explanation of planetaries ( that is worthless without pics) reverse is simply the directs and low gear being applied at the same time.

A trans brake is low, reverse (directs) and forwards applied at once...
For the direct piston to be used for both reverse and drive, they designed it to have two separate apply areas. One for drive or 3rd gear, the other for reverse (reverse actually uses both stock).

When you leave out the center seal, there is nothing separating these two apply areas ("chambers" as they are on an assembled direct drum)
So when it goes into high gear, the whole backside of the direct piston is applying force on the high gear clutches. Instead of about half of it.

Problem is, now fluid can back feed into the low/reverse circuit and apply the low band or clutches... then you'd effectively have a trans brake, not good as you are shifting into high gear...
So you have to block the passage that can back feed...

The reason you want the entire piston having fluid pressure behind it is simple hydraulics.
Area X pressure = force
So in stock form, say it is 10 sq/in. with 175 psi line pressure.
That is 1750 psi of force applied to the clutches.

If you bump up the line pressure to 250 psi with the PR spring, you now have 2500 lbs of force.
That is the difference in actual holding power that a TCI or other similar kit will give in high gear...

Now add another 10 sq/in. to the apply area...
Now we have 20 sq/in and 250 psi line...
5000 psi of holding pressure on the directs...

Here's the deal on the TH400,
TransGo is the ONLY kit that dual feeds without doing the internal mods. So it is the only kit you can install for dual feeding with a trans in the car.
They do so by using a sandwiched separator plate assembly... it is a patented deal that has 3 plates riveted together, the center one performing the same function as all the TH350 kits "transfer plate" but it is a little more complex due to the nature of the TH400's fluid passages in the worm casting area.

As far as other shift kits go, I cannot say without a doubt that it does not dual feed, I'm willing to bet they do not...

I have used TCI stuff and their kit is almost exactly like a TransGo but does not have the patented separator plate...
I like the TG kit for both a TH400 and TH350, however on the TH350's when I do a complete build I do not use any packaged kit, I internally dual feed, use a heavier PR spring, and drill the feed holes. I do NOT leave out any springs...
I also use heavier direct clutch return springs...

If you want to do all that why not turn the 2-3 accumulator piston upside down on the TH400, grind off the 3 tabs, and then re-install with no spring. NO movement, NO accumulation, KILLER hard shifts, and broken parts...
The same thing can be accomplished on a TH350 with a 3/8" nut on top of the piston..I don't suggest either...

On a TH400 going into a pretty stout car I usually drill the feed holes out to the upper end of TransGo's suggestions. ~.130-150"...

Inline

Thanks for commenting.

Thats actually why im asking. As im aware, for TH350 you dual-feed direct either with separator plate which connects two passages with add-on plate, or by removing center-seal on direct and from stator-shaft ( if i remember correct the name of that shaft) plus plugging the low/reverse passage with 3/8-24 set-screw. Theres also internet full of modifications, and from actual trans-builders, which provide means to complete everything shift-kits gives you by mods to trans itself; be it drilling some passage or plugging; removing spring or locking accumulator.

And here we come to this; its really vague what you really need to do and when; all seems to aim for drag-strip use. For street etc, maybe sudden strip use; what would you do? Something between; but what? Thats why it came to my mind, that what if i would remove the separator plates add-on plate which does the dual feed, and dual feed it internally. No harm done; nothing more to leak. Nothing un-reversible, and if i like how the trans feels, i dont need to worry about that added circuit starting to leak at some point.

This might make no sense, and i admit im not the best to express what i think with foreign language, but i hope you get the idea what im chasing after.