Flexplate replacement

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8T7K5

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While my Suburban is out of commission over some fuel injector issues I'm also going to replace the flexplate. Got quoted over 500 bills for a shop to do this and even though I've never done it, it doesn't seem too difficult and I'd like to save those Benjamins. The plan is to support the transmission with a tyranny jack, unbolt the drive shafts, use some all thread or longer bolts on the bottom two bolts, and slide the transmission back. Is it easier to just go in with some long extensions over the top of the transmission or with the upper intake out of the way is there enough room to get to the top bolts between the engine and firewall?
 

stutaeng

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I'm assuming it's a 2wd?

Removing the transmission crossmember and lowering it a bit allows you to get to the top-most bell housing bolts. This is to remove the tranny. Not sure what you are thinking about the all-thread? I'm a little confused about that.

Remove the torque converter bolts through the starter first, of course.

What's wrong with your flexplate?
 

thinger2

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Hes talking about using the all thread as a guide pin when you put the trans back in.
Ive used long bolts with the heads cut off and a chamfer ground onto the end.
I dont know if all thread will work as well because it might bend and it might hang up on the threads.
Using guide pins when you are wrestling it into place works great.
It lines up the bellhousing and allows you to take a break to get some circulation back in your arms without having to drop the trans because you cant hold it in alignment anymore.
You basically use the pins to guide the trans into place and as a way to "hang" the trans for a minute if you need to stop.
If you wanna get real tricky about it, make one pin a bit longer than the other.
Hang it on the long pin first and then rotate it up and hang it on the short pin and push it forward.
And, assuming you dont have a transmission jack, once you get the floor jack high enough, ratchet strap the trans to the jack head with some cheap ass straps so it doesnt get all sideways on you.
When you get it in place, cut the cheap ass strap if you cant get it to release
 
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Schurkey

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Use a L-O-N-G 1/2" to 3/8" adapter, and a swivel socket powered by an impact wrench to get to the bellhousing bolts. Since the main part of the adapter is sized as a 1/2" extension, there isn't as much "torsion-bar" flex as there would be with a 3/8-drive extension.

https://www.harryepstein.com/sockets-1-2-accessories-27792.html
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On my '88 K1500, most of the bellhousing fasteners have studded bolts with nuts holding the dipstick tube, fuel supply and return hose bracket, etc. I'm thinking that the nuts are smaller than the hex of the studded bolts. You'll need two sizes of swivel sockets if your truck is built like mine.

All-Thread is not very strong. Use a couple long bolts, head cut off, and the shanks chamfered as said previously.
 

8T7K5

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I'm assuming it's a 2wd?

Removing the transmission crossmember and lowering it a bit allows you to get to the top-most bell housing bolts. This is to remove the tranny. Not sure what you are thinking about the all-thread? I'm a little confused about that.

Remove the torque converter bolts through the starter first, of course.

What's wrong with your flexplate?

All thread was to keep the transmission lined up when it gets slid back/forward. It's a 4x4 in my 99 K2500 Suburban. Morons who had it before me told me one of the starter bolts had broken off. Had a guy supposedly remove the broken bolt. I'm not sure he did at this point but the threads in that bolt hole are pretty bad so that needs to be fixed in addition to seeing if the broken bolt has actually been removed. Because of all that, the flexplate has some bad teeth on it.
 

stutaeng

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I see. And so t case work as well...

That tranmission is insanely heavy. I'm assuming you are going to drain the oil, right?

The suggestion by @Schurkey is good.

Hopefully you have a torque wrench for the flexplate, as the bolts are torqued to spec, as well as the torque converter bolts.
 

Nad_Yvalhosert

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You'll need a minimum if 6" of space to get tools up and onto the flywheel bolts. There isnt enough room for you, tools, jack stands, tranny jack, etc, under the truck and in the transmission tunnel if you're working on your back, to go straight back on some kind of improvised "line-me-up" threaded rods.

Not to mention the wiring harness isnt long enough, so it must be disconnected. Then there's the shifter linkage, fuel lines, steel tranny cooler lines... Best just to drop it right to the ground and out.

So, it's a 4l80, right? Thankfully it has a torque converter cover like the 700r4. But, how're you getting to, and unbolting the converter if the starter bolts are NFG? And how are you getting the tranny and inspection cover past the exhaust y-pipe?

Sounds like that $500 is a screaming good deal at this point
 
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8T7K5

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You'll need a minimum if 6" of space to get tools up and onto the flywheel bolts. There isnt enough room for you, tools, jack stands, tranny jack, etc, under the truck and in the transmission tunnel if you're working on your back, to go straight back on some kind of improvised "line-me-up" threaded rods.

Not to mention the wiring harness isnt long enough, so it must be disconnected. Then there's the shifter linkage, fuel lines, steel tranny cooler lines... Best just to drop it right to the ground and out.

So, it's a 4l80, right? Thankfully it has a torque converter cover like the 700r4. But, how're you getting to, and unbolting the converter if the starter bolts are NFG? And how are you getting the tranny and inspection cover past the exhaust y-pipe?

Sounds like that $500 is a screaming good deal at this point

No dust cover. Previous owner removed that too. Like I said, I've never done this before, seemed like a practical way to go since others had done it with 4L60's. I didn't realize there were that many differences between the 60 and 80.
 

stutaeng

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No dust cover. Previous owner removed that too. Like I said, I've never done this before, seemed like a practical way to go since others had done it with 4L60's. I didn't realize there were that many differences between the 60 and 80.

The steps to remove the transmission are the same, regardless if it's a 4L60 or 4L80. The only difference is the 80 is a heavier unit. Physically I know it also larger. Maybe that why you can do the alignment deal you are talking about with the smaller tranny?

A new flexplate is going to be maybe $60? Not sure if the $500 quote already have that?

I removed the 4L60e on my truck recently and had to remove the exhaust y pipe, driveshaft and crossmember. Lowering the tranny with a jack allows room for the bell housing bolts as I had mentioned, as well as unhooking harness and oil dipstick.

But for installing it, a transmission jack is essential if you already have on. Make sure to ratchet strap the tranny to the jack plate.

Edit: then there's the transmission oil cooler lines...

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8T7K5

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$500 doesn't sound too bad. If it was as simple as just sliding it back I'd be a little more enthusiastic. Of course, I've still got to get that bolt hole fixed before I can get a new starter, which is another headache.
 
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