Replacing the flexplate without removing engine or transmission

[dmjlambert]

I thought some of you may enjoy these pictures. I replaced the flexplate without removing engine or transmission. My truck is a 1969 CST/10 with 350 engine and TH400 automatic transmission. I am a newbie for such an in-depth repair, so if I can do it anybody can. Some of you may recall a recent post of mine where I talked about chewing up my flexplate and needing to replace it.

First of all, the research. I found this interesting forum article:
https://ls1tech.com/forums/automatic...l#post18644698

The only special tool I ordered for the job was a Lisle Flywheel Turner. I highly recommend this tool, it is just great.
https://www.amazon.com/dp/B000FN7JE2/

I did some things slightly different than the article. I did not remove the driveshaft. Instead I just took loose the rear u-joint and the carrier bearing mount bolts, and rested the driveshaft on a strap so it could move front to rear with the transmission.


I disconnected the negative lead of the battery. Instead of removing the starter, I just loosened the inner bolt and remove the outer bolt, and rotated the starter out of the way.


I removed the parking brake cable guide that is right behind the transmission and pushed it up the cable and out of the way, and put a small bolt and nut in place, and hooked the cable under it. It is out of the way for when the transmission moves back. This picture shows the transmission already moved back.


I took out the flexplate-to-torque-converter bolts with help of the flywheel turner tool. I removed the various transmission connections and mount bolts. I put in the 4 long bolts one at a time, and took out the top 2 transmission bolts. I put a jack under the transmission to lift just a little bit of weight. It probably wasn't mandatory, but I thought it was a good idea. The truck was on ramps for the operation. My Home Depot was out of 4 inch 3/8 grade 8 bolts, so I got some 5 inch bolts. It worked great. The transmission slid back on those bolts with little effort, and what I saw was a big work area to get at the flexplate-to-engine bolts.


Here is what the flywheel turner tool looks like.

[terry b]

Look's like you have it under control. Good talking with you today. Good luck with the truck it looks like a keeper.

[randy500]

Nice Job! Bravo!
I have done that many times and I learned something today, glad I clicked on the post, never thought to use long bolts to slide it back on, I always pushed it back and propped it up with wood and such across the frame rails. I also like that you left the driveshaft in, much less mess and no fluid lost!

[randy500]

Oh and where did you get the flywheel turning tool? My snap-on one is just like that except a different handle, wouldn't mind getting another one if it were reasonably priced.

[dmjlambert]

Originally Posted by randy500

Oh and where did you get the flywheel turning tool? My snap-on one is just like that except a different handle, wouldn't mind getting another one if it were reasonably priced.

Amazon: https://www.amazon.com/dp/B000FN7JE2/
Just click and a couple days later here comes the tool.

[randy500]

Originally Posted by dmjlambert

Amazon: https://www.amazon.com/dp/B000FN7JE2/
Just click and a couple days later here comes the tool.

Sweet tool and price. I put one in my cart so I can find it later.

Do you know you can ratchet with it on the flywheel to get the proper span of teeth? I jam the tooth attached to the handle in the flywheel the move the handle to engage another tooth with the springed portion, then turn the flywheel, makes it quick to engage when rotating the flywheel to line up the bolts.
Another tip you may not know...each of the holes in the flywheel are elongated, 2 are the same elongated around the circumference. One is 90 degree opposite elongated. (from the center of the crank outwards) If you install that bolt first you can fully tighten it then when you turn the flywheel the others will line up because they are elongated around the circumference for the bolt to line up.
Saves time as you don't have to start all the bolts before tightening them up.

[dmjlambert]

I didn't know that. Good info, thanks.

[chris mc bride]

Works on old chevy,not newer dodge.I had rear seal go on 2005 dodge ram 4x4.Tried this.Did not work out as well. Congrads on working around extra work.

[custom10nut]

I'm in the process of doing the same thing. I've done it before. I'm replacing the starter and flexplate ate the same time.

[SonnyBoy]

Great post !!
I haven't had the pleasure..... yet .
Looks like the deal.
Time saver and like Randy said , much less fluid loss.
Thanks for the info.

[custom10nut]

That's a great tip with using the five inch bolts to keep things lined up.
I didn't do that when I replaced mine. It sure will make things easier.

[GASoline71]

All I would add is use a piece of wood, like a 3/4" piece of ply wood about 12" x 12" between that transmission pan and the floor jack.

Good job!

Gary

[demian5]

My dad and I did it on my 73 BB 2WD suburban. Not too hard, just needed enough room for hands and a torque wrench.

[BugzC10]

I did the same last year...drop drive shaft at diff, unbolt tranny at crossmember, 4 long bolts, slide tranny back & wala. Used the same tool also.

[abig84]

The longer bolt thing is a good idea. We used to run into a lot of 2000ish s10s with cracked flexplates at my old job. I just took all the bolts out and backed the top 2 halfway out and just let the gap happen. Had just enough room to get in there with box end wrenches.

[NJKelly]

I have a 72 coming tomorrow. PO said the ring gear needs to be replaced and I started researching how to do it and found this post. First off, thanks! So I've seen ring gear can be purchased separately but feel you may as well replace flexplate with ring gear at the same time. Do you recall where you bought your flexplate?

[Ol Blue K20]

Originally Posted by NJKelly

I have a 72 coming tomorrow. PO said the ring gear needs to be replaced and I started researching how to do it and found this post. First off, thanks! So I've seen ring gear can be purchased separately but feel you may as well replace flexplate with ring gear at the same time. Do you recall where you bought your flexplate?

A manual trans flywheel has replaceable ring gear. The automatic flex plate is welded so the whole flex plat must be changed.

[dmjlambert]

Originally Posted by NJKelly

Do you recall where you bought your flexplate?

I got mine through Amazon:
https://www.amazon.com/gp/product/B000C8RDCS/

I compared them when I took the old one off, and the new one was exactly the same.

[NJKelly]

Was this on a 2 wheel drive truck? I'm attempting this on a four wheel drive Blazer which with the transfer case may make it more difficult.

[AussieinNC]

The fact you could just remove one starter support bolt and turn the starter tells me the support bracket at the end of the starter is not in place...

I would make sure the starter support bracket is in place at the end of the starter when you put it back together....

These missing support plates are the number one reason the starters break out the outer mounting bolt hole in the ear on the block.

Nice work on the flex plate R&R ...

[dmjlambert]

It is 2 wheel drive truck, no transfer case. I do suppose it would be different for a 4 wheel drive truck. In 1969 there was no additional support bracket for the starter on trucks. I would like to get one anyway before I do anything to the timing that could cause kickback.

[AussieinNC]

Make sure the block is tapped for the bracket then...I just checked my 69...it has the bracket, as does my 67....maybe previous owners had em fitted...

[NJKelly]

Originally Posted by dmjlambert

It is 2 wheel drive truck, no transfer case. I do suppose it would be different for a 4 wheel drive truck. In 1969 there was no additional support bracket for the starter on trucks. I would like to get one anyway before I do anything to the timing that could cause kickback.

I used your method and got the old flexplate out. I did not have as much room to work as you because the transmission jack I was using was hitting the crossmember. I moved it once to allow the transmission to move back further and probably could have moved it a second time to get even more room but didn't really need it. I think I mentioned earlier in another post the driver side second bolt had to be 3in as it hit the firewall. The four was too long. Other than that I disconnect the transfer case to frame mounts and took off the rear drive shaft as there is no leaking problem and took off the front drive shaft as it connects to the differential. Got in front of the truck and started kicking the Jack hitting the front and rear wheels at the same time with my feet and was able to move the transmission without any problem whatsoever. I came back to this post to double-check the correct direction of the flexplate. Lots of conflicting information out there. Hopefully tomorrow with rain in the forecast my son and I will get underneath it and install new one. Looking at your pictures of your old flexplate it looks decent, mine the teeth look like they were hit with a hammer.

[dmjlambert]

Originally Posted by NJKelly

...Looking at your pictures of your old flexplate it looks decent, mine the teeth look like they were hit with a hammer.

It looks like in my pictures I did not show the parts of the flex plate where the teeth were ground up. It was really messed up bad, but had some good sections with some good teeth left. I could start the truck if the engine happened to stop at a place with good teeth where the starter engaged.

[NJKelly]

Originally Posted by dmjlambert

It looks like in my pictures I did not show the parts of the flex plate where the teeth were ground up. It was really messed up bad, but had some good sections with some good teeth left. I could start the truck if the engine happened to stop at a place with good teeth where the starter engaged.

Same with mine. I don't recall did you mention changing the starter as well? When I was searching for a flexplate at advance Auto website they actually sell just the cog for the starter as opposed to replacing the entire starter. Have yet to inspect mine to see if that needs to be changed out, the guy at the auto parts store said it's probably not in bad shape despite the flexplate being bad because it's a bigger bulkier piece of metal. We'll see.