Author Topic: Pulling 4-Speed trans and re-installing...  (Read 793 times)

nUcLeArEnVoY

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Pulling 4-Speed trans and re-installing...
« on: December 07, 2022, 11:20:05 PM »
Very last leak to chase on my '79 is a small leak at the original BW ST-10. After two and a half years of ownership, it's time to nip it in the bud and finally have a leak-free car. I think I may have narrowed it down to the midplate gaskets, but either way I have a full re-seal kit at the ready and this will call for removing the trans as a unit.

So removal seems easy enough, my question involves more around the shifter assembly, rods, and linkages. So say I unbolt the shifter assembly and the rods from the shifter shafts at the side cover, and tie all that stuff out of the way as specified in the service manual... SHOULD be good, right:? As in, once I re-install the trans and bolt it all back up, I shouldn't have to adjust anything, right? Should go right back to shifting the way it always did, assuming I bolt everything back up correctly, right? The trans works and shifts in all gears just fine, don't want to mess that up or god forbid have to adjust shifter linkages, because I hear that can be a nightmare. I don't want to mess up the settings/adjustment I already have,  and I don't intend to do absolutely anything new to the trans other than just replace gaskets and seals, even though that unfortunately means having to take a lot of it apart...

Just want to plan ahead in case when I reinstall the transmission and bolt back up the shifter assembly and rods, I have to make adjustments.

Also, is there a gear I should put the trans in for ease of removal/disassembly and re-installation? Keep it in reverse (i.e. lockout), or shift it into neutral or what?
1979 Trans Am 400/4-Speed W72/WS6 - Starlight Black Hardtop

81Blackbird

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Re: Pulling 4-Speed trans and re-installing...
« Reply #1 on: December 08, 2022, 04:10:22 AM »
There should be an alignment hole/slot on the shifter base.  This will place the shifter in the neutral position and lock it into place.  Then, it's a matter of adjusting the length of each
rod, if needed, so that it slips into each of the transmissions "dog tags" on the side of the transmission.

I leave mine in first gear with the yoke in the tail shaft housing.  I find it easier to replace the trans should the spines not match up. A SMALL amount of grease or light weight oil helps
when placed on the raised portions of the input shaft and clutch disk.

b_hill_86

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Re: Pulling 4-Speed trans and re-installing...
« Reply #2 on: December 08, 2022, 06:59:50 AM »
Been a while since I messed with pulling my trans or messed with the rods but I’m pretty sure the factory shifter has lock nuts that prevent the length of the rods from being altered unintentionally so you should be good. As long as the rod length isn’t altered, and you’re happy with how it shifts now, you should be back in business when you reinstall.
-Brian-

1977 Trans Am 400 4 speed

ryeguy2006a

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Re: Pulling 4-Speed trans and re-installing...
« Reply #3 on: December 08, 2022, 08:40:09 AM »
Just make sure to take a lot of pictures before you take it out. It is very easy to install those brackets upside down and then your shift pattern will be backwards.  :cool:

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phil400

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Re: Pulling 4-Speed trans and re-installing...
« Reply #4 on: December 08, 2022, 04:47:50 PM »
It's not fun pulling the transmission laying on your back even less fun trying to stab it back in through the throw out bearing and lining it up with the clutch and pilot bearing. If I was pulling the trans I'd probably replace the clutch and pilot bearing while in there. Jmho
78 T/A 4 speed, original paint, match #s, mine since ‘99, 3rd & final owner as long as I'm alive.
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Re: Pulling 4-Speed trans and re-installing...
« Reply #4 on: December 08, 2022, 04:47:50 PM »

b_hill_86

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Re: Pulling 4-Speed trans and re-installing...
« Reply #5 on: December 08, 2022, 11:24:32 PM »
Good point. A transmission jack or an adapter is your friend too. I ended up making a crude one but it made things so much easier
-Brian-

1977 Trans Am 400 4 speed

nUcLeArEnVoY

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Re: Pulling 4-Speed trans and re-installing...
« Reply #6 on: December 10, 2022, 11:13:28 AM »
One thing I actually did prepare myself for is I made some guide pins that the service manual recommends, which are basically just some 3" long headless threaded rods you thread into bolt holes on the bellhousing that the trans mates to in place of the trans bolts as you remove them, allowing you to index the trans back and forth on a linear plane, so that will make things just a tad easier. I'll have no choice but to do this on my back without an adapter, but I can at least use my floor jack to lift the trans if need be since the front of the car will be up on jack stands.

My main concern was if when I reinstall everything, if I'd need to adjust the shifter assemblies and linkages... hopefully not.

I know that if I can successfully drill out and retap the original threads in the cylinder head of THREE snapped exhaust manifold bolts all with the engine and head still in the car (probably the most nightmarish repair I've done with this car), I can do this.  :lol:
« Last Edit: December 10, 2022, 11:20:47 AM by nUcLeArEnVoY »
1979 Trans Am 400/4-Speed W72/WS6 - Starlight Black Hardtop

81Blackbird

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Re: Pulling 4-Speed trans and re-installing...
« Reply #7 on: December 10, 2022, 12:27:05 PM »
I would head to Harbor Freight and pick up two jack stands and jack up the back of the car.  Having the car level would be so much easier and will give you more room to work.  Don't be too nervous
about the shifter rods.  They are easy to realign.  Just remember to set the shifter with the keyway in the locked position.  Things may have shifted a little which would make adjustments necessary anyway.  Great idea about the alignment pins for the bell housing.   

nUcLeArEnVoY

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Re: Pulling 4-Speed trans and re-installing...
« Reply #8 on: December 10, 2022, 01:11:35 PM »
I would head to Harbor Freight and pick up two jack stands and jack up the back of the car.  Having the car level would be so much easier and will give you more room to work.  Don't be too nervous
about the shifter rods.  They are easy to realign.  Just remember to set the shifter with the keyway in the locked position.  Things may have shifted a little which would make adjustments necessary anyway.  Great idea about the alignment pins for the bell housing.

Okay, and where is this keyway you're referring to?

And so you always put it in first gear before pulling the trans?
1979 Trans Am 400/4-Speed W72/WS6 - Starlight Black Hardtop

81Blackbird

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Re: Pulling 4-Speed trans and re-installing...
« Reply #9 on: December 10, 2022, 02:08:34 PM »
This should give you a good overview.  Allen wrench was the easy was to show you. A properly sized pin is best.

https://imgur.com/YLGcY1t

https://imgur.com/YXgOO0z

https://imgur.com/peBgKvW
« Last Edit: December 10, 2022, 02:13:27 PM by 81Blackbird »

b_hill_86

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Re: Pulling 4-Speed trans and re-installing...
« Reply #10 on: December 10, 2022, 02:34:28 PM »
I’d agree on raising the back of the car. It’ll make it easier to get the driveshaft out and the trans.

I would consider removing the trans from the bellhousing first then the bell. That’s how I’ve done it anyway and it seemed to work well. Not that it probably wouldn’t work with the bell.

As for the shifter, see in the one photo where I have the T-handle Allen wrench. In the other photo is a white “alignment tool” that came with a rebuild kit. Either way, with the shifter installed, in neutral and the rods disconnected (assuming they’re not adjusted properly) insert the alignment tool or something of similar diameter so the shifter can’t move around) and adjust the rods till they fit in the appropriate levers on the trans. This can be done with the trans out of the car.

Again though, I circled in red the nuts on the rods. They shouldn’t move if they’re tight and not messed with so if you’re happy with where things are they should stay there.

-Brian-

1977 Trans Am 400 4 speed

b_hill_86

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Re: Pulling 4-Speed trans and re-installing...
« Reply #11 on: December 10, 2022, 02:35:52 PM »
Also a good time for a shifter rebuild if there is any slop in it. Not difficult other than needing to make a tool to help reinstall the springs in the carrier.
-Brian-

1977 Trans Am 400 4 speed

81Blackbird

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Re: Pulling 4-Speed trans and re-installing...
« Reply #12 on: December 10, 2022, 03:26:55 PM »
Sorry I miss under stood...I agree with b_hill_86  Put the bell housing on first and then use the guide pins to get the trans in the right position.  Something I will do next time.
You can do the rod alignment outside the car but I don't see the need to assemble then disassemble and then reassemble the unit.
There is a little trick that racers used to do to make the 2 - 3 shift easier.  After getting the rods aligned, make the 1-2 rod slightly shorter and the 3-4 rod slightly longer.  One turn of each of the
pivot points.  This will in turn "shave off" part of the 90 degree slot of the H-pattern on the shifter making it easier to hit 3rd gear.  If your not racing, there is not point in that procedure.

nUcLeArEnVoY

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Re: Pulling 4-Speed trans and re-installing...
« Reply #13 on: December 10, 2022, 09:16:31 PM »
But wait, do I need to even remove the bell housing at all??
1979 Trans Am 400/4-Speed W72/WS6 - Starlight Black Hardtop

b_hill_86

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Re: Pulling 4-Speed trans and re-installing...
« Reply #14 on: December 10, 2022, 11:08:05 PM »
No not really unless you plan to replace the clutch, T/O bearing or pilot bushing. Great time to do so but otherwise no.
-Brian-

1977 Trans Am 400 4 speed

Re: Pulling 4-Speed trans and re-installing...
« Reply #14 on: December 10, 2022, 11:08:05 PM »

tajoe

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Re: Pulling 4-Speed trans and re-installing...
« Reply #15 on: December 11, 2022, 06:01:56 PM »
But wait, do I need to even remove the bell housing at all??
If you've put over 30K on the clutch, a new disc and TOB would be a good investment. The diaphragm pressure plate should be OK if you don't see a bunch of obvious discrepancies. Unfortunately the price of parts have risen to a pathetic level, and if you're tight on $, don't drive it much, and it's workin fine, leave it alone.
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scarebird

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Re: Pulling 4-Speed trans and re-installing...
« Reply #16 on: December 11, 2022, 11:36:25 PM »
Leave the bellhousing, pressure plate and disc alone with that low of miles - they are perfectly aligned.
 you can slide in a new throw out bearing if desired.

nUcLeArEnVoY

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Re: Pulling 4-Speed trans and re-installing...
« Reply #17 on: December 12, 2022, 04:55:15 PM »
Yeah, guys, I was gonna say, the car shifts just fine and there's no slippage or even inkling of evidence the clutch or throwout bearing/pressure plate are bad. The engine was rebuilt at some point, and it wouldn't surprise me if the clutch and pressure plate are also newer as well. Literally all I need to do is just pull the trans as a unit and reseal it... which I'm sure in and of itself will be a huge pain in the butt, but thank the gods for the GearBox vids on YouTube lol.
1979 Trans Am 400/4-Speed W72/WS6 - Starlight Black Hardtop

b_hill_86

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Re: Pulling 4-Speed trans and re-installing...
« Reply #18 on: December 12, 2022, 06:18:28 PM »
Yea if you’re talking about Paul he is super knowledgeable and helpful. I called him looking for a thrust washer for the reverse idler gear in my trans. Super helpful. Pulling the trans isn’t bad. As said, make sure you have enough height and unless you have two sets of hands, I’d snag a trans jack adapter from harbor freight. I pulled mine without once and it was doable but sketchy. Not worth cracking the aluminum case. Needed two hands to reinstall. Did you watch the videos I sent you? The jack adapter I made made a world of difference.

Pulling the tail case off isn’t bad. I opted not to pull the front of mine apart when I resealed it.
-Brian-

1977 Trans Am 400 4 speed

ryeguy2006a

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Re: Pulling 4-Speed trans and re-installing...
« Reply #19 on: December 13, 2022, 07:46:59 AM »
Yep, don't let scope creep kick in. Fix the leak and reinstall. If you give in scope creep will kick in and next thing you know, you have installed 3 motors 2 transmissions, 2 ECU's and 7 years has gone by. Ask how I know haha

1976 Trans Am LS1 and much more...SOLD
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roadking77

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Re: Pulling 4-Speed trans and re-installing...
« Reply #20 on: December 15, 2022, 08:36:54 AM »
How can I tell what the correct bell housing is?  I have a 79 400 4 speed, drive train was in pieces when I got it. I have 2 bell housings and no idea which if even one of them is correct?
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b_hill_86

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Re: Pulling 4-Speed trans and re-installing...
« Reply #21 on: December 15, 2022, 10:57:46 AM »
Pics?
-Brian-

1977 Trans Am 400 4 speed

Re: Pulling 4-Speed trans and re-installing...
« Reply #21 on: December 15, 2022, 10:57:46 AM »
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