Replacing the flexplate on a GM ZZ502/502

Have a starter that will not mesh. Checked the flxplate and it is showing some serious flat spots. I just got a new flexplate from GM and am getting ready to install it and could use some pointers.
Engine is a ZZ502/502, tranny is a 700r4, in a 94 Yukon 4WD. I will be doing this in my garage. This is my plan, please point out any obvious errors

Drop the front and read drive shafts
Support the tranny with a floor jack and some wood
unbolt the torque converter from the flewplate (I have to turn it a little to get to all the bolts)
Unbolt the bell housing from the engine (I think it's 4 bolts, at least that's all I can see)
unbolt the tranny from the crossmember supporting it
Slide the tranny back a few inches
Remove the flexplate
Install the new one, and put everything back where it belongs.

Does this sound like it will work? I really do not want to pull the engine (I do not have a hoist) and I don't want to pay $300.00 to have someone do it for me.

What are the major pitfalls I can encounter.

The engine is fairly new, only about 2000 miles on it, the tranny is 2 months old with only about 100 miles on it. The guy I bought it from shimmed the starter out wrong and messed up the fleplate, now it eats starters, and at $129.00 a pop for the autozone gear reduction starter, eating them ius not a good thing.

any suggestions would be greatly appreciated

thanks, John

sounds good to me .but on the trans use longer bolt on the block 4 1/2 to 5 the bottom two is will let you slide it back an keep it off your head the dip tube will have to come out six bolt hold the trans on a chevy and the trans cooler lines shifter link and kick down cable have to come off. trans oil will come out of tail shaft and trans lines so watch out put the drive shaft back in to keep the oil from making a mess. shiming starter can be a pain alot of times they need to go up if you know somone with a mill it can be done or use a big file the air gap should be 0.25 some of the gear reduction starter do not fit great you will have to play with it:whacked:

Quote:

---

Originally posted by DennyW
:) There should be 6 bolts in the bell housing. A safety, if you have the room, is take the left and right bell housing bolts out, install 2 long bolts that will give you up to 3 inches of room. That way, you can support the trans with a jack and blocks, and let the trans slide back on the 2 long bolts. Once you get the flywheel changed (flex plate), you can bolt up the starter, and check the clearance.

---

ya'll making that look to easy. :HMMM: :whacked:

I have no illusions that this will be easy. I have never attempted doing something like this will the engine still in the car, but I don't have much choice. There are two nagging problems.

1. I like to do stuff myself, no point in having a hotrod that you don't wrench on.

2. I don't have the 300+ bones just laying around to pay someone to do it for me.

I don't think there is much in the way of linkage since the tranny shifts electronicaly. How much fluid do you think will leak from the driveshafts after I drop them?

Thanks a-lot guys for the tips.

John

the tough part is getting the trans oil out of you hair .but dawn works good and it works on oily ducks quack quack:LOL:

Quote:

---

Originally posted by ScjohnK
I have no illusions that this will be easy. I have never attempted doing something like this will the engine still in the car, but I don't have much choice. There are two nagging problems.

1. I like to do stuff myself, no point in having a hotrod that you don't wrench on.

2. I don't have the 300+ bones just laying around to pay someone to do it for me.

I don't think there is much in the way of linkage since the tranny shifts electronicaly. How much fluid do you think will leak from the driveshafts after I drop them?

Thanks a-lot guys for the tips.

John

---

i was just joking youll do ok. keep the trans about leval and if its not over full you shouldnt loose a lot. i thought they had yokes on them , if they do you wont loose nothing.

I'm in the Army, not much hair to wash it out of, however, if it gets too bad, I can just shave it off and it'l grow back in a month:LOL:

i have done 400 trans but it will be the same way how much trans oil will you lose ?? put the drive shaft back put a pan down if it is leve not much?? i do not kown it is hard to say sometimes pulling the drive shaft out can make it come out from the drawing out the drive shaft**)

it's a 700r4, basicly a turbo 350 with overdrive. It's also 4WD which just makes this job even more of a pain. My only experience with 4WD vehicles has been working on Hummers in the Army. Just more crap to get in my way tomorrow when I tackle this beast.

Well, it has all been going quite smoothly, only one problem. Does anyone have a suggestion as to how I can get to the top 2 bolts on the bell housing. Once I get this one tackled, the rest should be smooth sailing

A couple of the guys suggested that I put some long bolts into the 2 bottom holes on the bell housing to allow me to slide the tranny back out of the way with greater safety. Does anyone have a suggestion as to where I can find some 4-5 inch long 9/16 bolts that are long enough. i'm out here in BFE and do not have a lot of stores to get stuff from. Any idea wether auto zone or O'Rileys would have something like this? Or any suggestions of something that I could use that I would have like alternator or starter bolts? I don't want to mess up the threads in the block, so trial and error are out. I was hoping that some of you experts could enlighten me as I am as shade tree as it gets.

I got the top 2 bolts out. I actually had enough clearance between the engine and the firewall to get my hand behind it. I could not believe it, but it's true.

Also need to know what to torque the flywheel bolts to, the torque converter bolts, and the bell housing bolts once I am ready for reassembaly.

I know.... I ask a-lot, but I really do appreciate it

Thanks guys,

John

P.S. If you want to see what a ZZ502 looks like in a Yukon, check out my album

i have used two starter bolts they are 3/8 16 NC they can be grade 5 . any hardware should have them .it s is hard to get a to torque wrenche in there .' but i have a built in torque in my arm ' ha ha
i use threadlocker loctite on them crank to fly wheel 65. and conveter ??? uses threadlocker and say 45 to 50 this should give you a ideal on the torque. :whacked:

I mentioned this on another thread, but it bears repeating. Be dam sure you get the flex plate in the right way! Some aftermarket ones don't have a lip,on the center hole, making it possible to put it in backwards. The right way puts the ring gear closer to the engine so the starter engages all the way.

it's not aftermarket, it's GM performance products, and they must have seen this happen a-lot too since they stamped "Engine Side" on the inside of the flexplate

Thanks,

John

What, you read directions?????

so "engine side" means face it towards the tranny right????:confused:

if it has a lip on the auto fly this faces the trans engine side faces the engine

LOLOLOLOLOL:LOL: :LOL: :LOL: :LOL:

Denny and Pat, your suggestion of using the long bolts on the bottom 2 bell housing holes was pure genius. It worked perfectly. I did not even need a tranny jack I just unbolted the crossmember from the chassis and slid the entire thing back. thanks a-lot guys

Here's another pic of one of the bolts. I used 2 really long alternator bolts, and they worked perfectly.

one last question (hopefully), is there anything special I should know about flywheel bolts? Is there a trade secret for removing these things? I cannot get any of them to budge. It's only supposed to by 65lbs of torque, but GM did not read their own manual, either that or they put loc-tite on them. Are they reverse thread by chance? I have spun a socket (6pt) on one already and have tried the Craftsman bolt out kit on one of them with NO LUCK.
Seems every time I think I have this thing licked, it bites back.

Thanks,

John

I was using a 6pt socket and 18" breaker bar. I managed to get 3 of them off, but cannot get the other three to budge. The socket keeps wanting to turn on the bolt head. When I got the other 3 out I did not see any loc-tite on them. I do not want to do any more damage to the bolt heads than has already been done. And, like I said earlier the craftsman bolt out kit is not doing much, I don't think it was designed for this kind of torque.

14mm is what i'm using, 9/16 is the right size I believe but is a little too loose, so I have been using the 14mm, this is the one I used for the 3 bolts that I got out.

okay, I'm off to wal-mart to get a torch. I don't have any 6pt wrenches though. Gonna have to keep using my 6pt socket with a breaker bar. I wish I had a welder so I could just weld a bar onto the head and get it off that way.

yes denny is rigth i think the heads are metric 17mm?they use to be 11/16 and i had a short socket for them. i learned the bolt trick over 20 years ago. dont tell NO one.it is killer :HMMM:

then it 14 mm you do not have to get it that hot to breake the locktite .BE CARE FULL NOT TO SMOKE THE REAR SEALWITH YOUR TORCH OR YOU WILL BE LOOKING AT REAR SEAL TO:whacked:

Having some problems getting them cherry red, or red at all for that matter. I don't have acetalyne at the house and am using a propane torch designed for sweating pipes. I heated them up a few times, and sprayed them down with some penetrating oil. I do not have, and cannot find a 14mm 6pt wrench, so I am going to try a new type of plier that vise-grip has come out with. The jaws are specially designed to grip hex bolt heads. I'll get back with how well everything worked, or did not.

John

These are those Vise-Grips, anyone have any experience using these? I really don't want to have to get a flywheel bolt machined out of the head if I totallt F**K this one up. I already bought new flexplate bolts so I don't care if I destroy these, I just want to get the damn thing out

John

i can say i have not. but i do not likes the looks of them .they looks to thick ??try to find a six point wrench or try to fine one on line or snap off or mack??i have a 11/16 3/8 drive i used with a breaker bar .six point 14 mm 3/8 drive with a breaker bar ?? try hiting the side of the bolts with a drift punch don t they have a shoulder on them hit them at the base of the bolts if you got them hot the loctite is broke if not try heat them do not cool them heat one at a time look out for the rear main seal :whacked:

great thanks for all the great tips. The vise-grips were too thick, I could not get a hold of the bolts. I finally said screw it and went for broke. I hammered the Craftsman #8 Bolt-Out onto the bolts and applied even pressure, while pushing the socket onto the bolt at the same time (to ensure it did not slip), well, between the heating, the hammering, the penetrating oil, and the bolt out kit, I finally got the three off. I got enerything reassembled. I am still having problems with the starter though. It will engage, but only cranks once, then I hear the motor going, but the cog on the starter will not spin. I am not sure if I need to shim the starter or not, since this is what caused me to have to replace the flex plate in the first place. I do not want to have to go through this again. according to GM, the starter should not require a shim, since it is a new motor.
Has anyone had problems using the high torque gear reduction starters from Auto-Zone?
Any idea what could cause the starter to engage, spin one revolution, and them just stop spinning the cog, opnce again, I can hear the motor spinning, and the cog stays engaged to the gear ring, but no spinning.

Thanks,

John

if you take the starter apart so you can push the bendixs in and out by hand when you take it apart bolt it back on the block you will have the aluminum block and the bendixs is set in the aluminun block if you can pull it in and out of the fly wheel there is a air gap 0.20 or more 030. it will work if not you have to shim it or trim the aluminum block down you can use a thick paper clip to check air gap this the teeth on the fly wheel and the bendixs mesh at the root of the teeth is the air gap i did tell you how to do this before . i have used the gear drives and the stock type some things you have to work on to get it rigth:whacked:

If the starter turns but the pinion doesn't, the drive is shot. There's an over-running clutch in it that's slipping. From your pix, the ring gear didn't look that bad, seen lots worse that still worked,but then the part that didn't show could be worse.