Dropping the TH350 1980-82 Years?

[HammerDown]

Long story short...seeing ATF just above the trans-pan and just inside the trans case lip, it appears my TH350 has to come out > (all other leak points have been addressed) I believe it's leaking at the pump input seal.

So, the car is off the ground, drove the front up on ramps and the rear wheels are blocked-up a little higher than the fronts...plenty of crawling room on the ground...yuck.

The front Y-pipe is off.

Besides the driveshaft being removed, trans cooler lines being removed and the crossmember needing to come out to drop the rear of the trany some...what else am I up against???

Can anyone tell me (for sure) how much ground clearance is needed to slide the TH350 out from under my car?

Not looking foward to this job, thanks for any feedback.

 

[Peer81]

Ray! Really, what are you getting yourself into!?

You're moving up the ladder with "I do all the impossible crappy jobs first" in a amazing rate!! :BOW

For me the easiest way to remove the trans is to take out the engine and the trans. But as I read your progress I think this isn't a option anymore. I've never done it this way but here it goes. The biggest problem you have is that the engine trans combination is sitting on the chassis at 3 points. The 2 engine mounts and the rear transmount. So if you remove the trans you'll need to find a way to support the engine or it will flip backward! Supporting it at the oilpan isn't a good idea but you can support it at the rear (at the clutch) or if you remove the oilfilter support it at the oilfilter inlet. Or if you have something like a hoist it would be much easier to support the engine. Then disconnect everything as you already did. Support the trans with a good thick garage jack (you still need to move it backward to clear it from the engine, so make sure you have enough support below the trans so it doesn't slide off the jack). The torqueconverter is connected to the flexplate with 3 bolts. Loosen the first bolt but don't remove it and keep it till last, turn the flexplate and remove the other two. Then remove the last bolt. Now try to move the trans backward to clear the engine dovel pins. Now the engine is on it's own and the trans too! Lower the trans and if you can't remove it from under the vette try to get the trans off the jack for extra clearance.
To be honest, this isn't a job you do on your own! If your under the vette and something goes work you just don't have enough strenght to keep the engine or trans under control!

If you use a hoist the engine and trans will be hanging in the hoist so no worry about things falling or sliding off. Much saver to me
I'll measure my th350 (from bottom to top) as it is sitting in a corner.

Greetings Peter

 

[HammerDown]

Peter, as usual thanks for the feedback.

Using my hoist isn't an option...my garage is just way to small!

If using a large enough piece of 2x10 (to spread the pressure) I didn't think supporting the engine under the Pan would be too bad, but I like your idea about using the oil filter boss.
BTW, I know 'some' people use the pan-rails for support too.

Knowing how tall the TH350 is from floor to the very top is important...so if you can, thanks for getting that for me.

 

[Hib Halverson]

If you have the front wheels on ramps and the rear tires on blocks, you're likely not high enough.

An automatic is tall because the trans case includes a bell housing so you need a lot of room. Plus, you're going to need extra height because the trans will be sitting on a transmission jack.

 

[HammerDown]

If you have the front wheels on ramps and the rear tires on blocks, you're likely not high enough.

An automatic is tall because the trans case includes a bell housing so you need a lot of room. Plus, you're going to need extra height because the trans will be sitting on a transmission jack.

"transmission jack"...no such luxury, I'm talking maybe a floor jack to aid it down then, onto the garage floor and slide it out from under the car.

I just visited a few transmission repair shops, got prices if I bring the transmission to them or, I let them take it out of the car.

As with my recent diff/rear suspension rebuild (that I ended up doing) I just don't seem to trust anyone and feel I'll get charged for a "full rebuild"...and get minimum parts replaced.

 

[Peer81]

The transmission is 42 cm high at the front. If you want to make this work I think it only can be done if the car is level off the ground.

Greetings Peter

 

[HammerDown]

The transmission is 42 cm high at the front. If you want to make this work I think it only can be done if the car is level off the ground.

Greetings Peter

Centimeter, what's a centimeter??? lol

I had to visit the conversion chart, 42 cm = 16.535450

My under car clearance is 16.50 (inches)

I can raise the rear of the car a few more INCHES...that should do it.

 

[Peer81]

A cm? Welcome to my world. But after 10 years i know 1" is 2.54 cm!

I included 1 cm extra to be on the save side so it should fit. When the trans is on the floor you can also lift the tailpiece so the front drops about 1" I think.

Greetings Peter

 

[Yellow81vette]

Wow. I just can't see that being done on ramps. The bellhousing wont clear, especially if you have a jack of some sort under the tranny. Even if you drop it on the floor I still don't think it will clear on ramps. I switched to a 700R4. Had to shorten the drive shaft and get a Bowtie crossmember.

 

[TimAT]

I've been pulling transmissions for years with the front on jackstands. Raise it as high as you can, drain as much trans fluid as possible. Drop the trans with a floor jack then slide it off on the floor. remove the dipstick tube and drag it out from the front. Putting it back in is pretty much in reverse- stuff the trans under the car about where it goes then muscle it up onto the floor jack. It's handy to have some help.
I always pop the distributor cap too. Letting the rear of the engine down, if the cap is close to the firewall, it won't hit if it's not secured to the engine.

 

[HammerDown]

Like I said, if I can help no suspension will hang!
Finally made the front stands...maybe over kill but it's SOLID!

As you can see...I'm working in a 9' wide garage...very snug!

I purchased a used Transmission Jack (great condition) $60 bucks!

*Frame cross-member will be coming out
*Drive Shaft will be coming out

*Question...to access the upper transmission bolts, anyone know how much the trany/engine will need to be tilted down?
If I can help it, I'd rather 'not' remove the distributor.
Also, how much tilt can the engine mounts take before they're destroyed?
BTW...not enough room to pull the trany out from the front of the car...it has to come out the drivers side.

​

 

[TimAT]

No need to remove the distributor- just take the cap off. Leave the wires on it, just unlatch and set it off to the front or side- where ever it wants to go. Plenty of clearance that way.
I have a long extension- 3/8 male on one end and 1/2 female on the other. I use a 9/16 impact wobble socket and a good 1/2 impact to take out the upper bolts. Or use a wrench on them from the top if you can get your hand down there.
As far as the tilt on the mounts, they won't go much- if they drop the back of the engine over about 3" they're already dead.
Too close to get the trans out the front? How about just getting it past the front crossmember and then sliding it sideways out the corner? Worst case, you can remove the convertor while it's still under the car and then tip the rear up to slide it out the side. It'll be a bit messy, the convertor will dump a little fluid when you pull it, and then you'll get a bit more when you tip the rear up. Not terribly messy, but expect some fluid.

Looking at your picture, you won't have to tip it much to get it to clear the frame.

 

[HammerDown]

No need to remove the distributor- just take the cap off. Leave the wires on it, just unlatch and set it off to the front or side- where ever it wants to go. Plenty of clearance that way.
I have a long extension- 3/8 male on one end and 1/2 female on the other. I use a 9/16 impact wobble socket and a good 1/2 impact to take out the upper bolts. Or use a wrench on them from the top if you can get your hand down there.
As far as the tilt on the mounts, they won't go much- if they drop the back of the engine over about 3" they're already dead.
Too close to get the trans out the front? How about just getting it past the front crossmember and then sliding it sideways out the corner? Worst case, you can remove the convertor while it's still under the car and then tip the rear up to slide it out the side. It'll be a bit messy, the convertor will dump a little fluid when you pull it, and then you'll get a bit more when you tip the rear up. Not terribly messy, but expect some fluid.

Looking at your picture, you won't have to tip it much to get it to clear the frame.

Great info, thanks!
With the way things have been going I'll assume the mounts are shot.
What I can do, once the trans is down, I'll wrestle in of the Trany jack and then it will easily slide out from the drivers side. Think I have some 22" from floor to undercarriage.

 

[HammerDown]

Update...
finally got back on the transmission job...working with a bad shoulder in a 9'wide garage makes for slow going but I decided to pull the Dizzy, this allowed me to remove the two top trans bolts.

Also, by pulling the Dizzy, it exposed a pressure sender that's mounted at the rear of the intake manifold > that would have snapped off for sure!

Being the rear of the car's wheels/tires are sitting on blocks it's going to be difficult to remove the driveshaft...but I'll figure something out.

 

[HammerDown]

It's finally out!
Using my trans-jack, I was sweating the car may not have been high enough.
Only dropped the engine maybe 1" and it came out like butter!
Then, by using the 'tilt' on the trans jack I was able to just get it out from under the car...just behind the front left wheel.

Now the hard part, tearing into this thing and seeing what parts 'hard parts' may be needed.

*first, I need to find out what way to let the trans sit/hang to drain as much fluid out of it as possible...don't want this thing hemorrhaging all over my basement/workshop.

 

[Peer81]

Congratulations!!
Good moment to put a drain plug in the trans pan. Best way to drain it? None...
I really atmire your courage!

Greetings Peter

Verstuurd vanaf mijn GT-I9195 met Tapatalk

 

[Evolution1980]

I have some recollection of dropping my trans. Did not enjoy it! Enjoyed even less the process of putting a 7400R4 in there!
What's the reason that you're subjecting yourself this?

 

[HammerDown]

I have some recollection of dropping my trans. Did not enjoy it! Enjoyed even less the process of putting a 7400R4 in there!
What's the reason that you're subjecting yourself this?

The reason you ask, its had a leak that was getting worse. I hoped the leak was from the pan gasket or the other usual places...not so lucky, it's internal.
Being I have trust issues with my local shops and they're just gorillas that would break something and say "it was already like that" I opted to take on this job myself. The trans shifted fine etc but I figure with the miles on it and it's age I will just go through the whole thing.
Over the many decades I've always had my hands on tools and wrenches.
Last time I dropped a transmission I was 16 and the year was 1975 for my 1969 SS BBC Chevelle. Now being 56 with bad knees, back and a tore rotators cuff I can say this has not by any means been enjoyable.
But as mentioned prior...I have trust issues with the local shops and their gorilla mechanics.
Gotta admit, interest levels and the physical ability to do these big jobs is fading fast...and...nothing on these cars are easy to work on. The only fun thing about them is driving them. It may be getting time to where I just start selling stuff vs always repairing them.

 

[HammerDown]

Who made a lower drum spring compressor...this guy that's who!
The trans is fully apart...all rubber o-rings/seals were hard like plastic. The large pump o-ring was also like plastic and cracked as soon as I tried to remove it. That's where me leak was coming from.

The front clutches and steels look new... All steels look great without any burns or discoloring etc. The 1'st gear clutched 'may' be wore, not sure as they don't have the ridges like the other clutches.

So far the only viable problem I see...the front planetary gear is missing a thrust washer and the gear has visibly eaten into its case. So far that looks like the only 'hard' part I may need. This is where I was seeing some silver dust when changing fluid.
BTW, chatting with Tim/AT and his suggestions and feedback was paramount...big thanks!

 

[TimAT]

Don't forget to check the Torrington bearings-- Use a big socket or piece of pipe, load them up a little and turn. If you feel ANY roughness, now is the time to replace.