This is out of an 03D2 that I bought which ran fine but would not pull. PO says he was driving along and started hearing a loud noise from underneath and truck stopped pulling, he towed it home on a trailer, thought is was the transmission, didn't want to spend the money on a trans, so that's when I bought the truck.

I figured it was the flexplate from listening to it and here it is now that I have it out.

My questions are: Why did this break? Was it from the stress cracks in the flexplate that caused it to finally break? I see cracks running out from center toward outer edge. Or was it something else that caused this? like the trans broke and caused the flexplate to break?

I thought at first maybe someone had pulled the trans for whatever reason and didn't install the torque converter correctly and caused the flexplate to break but, could see by the buildup of dirt and grease on the trans and bellhousing bolts that the trans has not been out for a long time if ever.

After removing this and looking at the torque converter, it does not have any slop or play up or down or side to side and seems like it's seated properly and no fluid dripping into the bellhousing. I can turn the torque converter by hand and it feels like it is in there all the way like it should be. I tried turning it 180 degree and 360 degree and pushing hard on it just to see if it would click in any further and it would not. I put a straight edge across the bellhousing mating surface and it is 1" back to the flexplate mating surface on tc. Don't know how far in it is supposed to be? Looks like from the mating surface on back of engine to back of flywheel 1" is about right?

Just wondering if any way to tell if I may have more damage in the trans other than putting it all back together with a new flexplate and seeing if it will pull?

 

That is some serious damage!

You might find this info useful: Cracked or Broken Out Center of Flywheel

• Worn or broken engine and/or transmission mounts.
• A rebuilt torque converter and/or front pump was installed on the transmission during a transmission rebuilt. Rebuilding the torque converter and/or front pump removes metal and increases clearance at the flywheel.
• Out-of-balance engine, harmonic balancer or torque converter.
• Worn front pump bushing will cause excessive movement of the torque converter.
• Failure to install the flex-plate perpendicular to the crankshaft recess area and/or over-tightening of the flex-plate bolts, tightening the bolts in the in-correct sequence
• Sudden shock to driveline-"neutral drops" (high engine r.p.m. in neutral and then dropping into drive), racing etc.

 

Thanks for the link and info.

It probably wasn't such a mess initially but, I had to run/idle the engine for 30 minutes before I bought it to be sure the engine ran good and wasn't overheating or ticking. It was making all kinds of noise down there and probably wrecked the flexplate a little more but hopefully nothing else?

 

"Was it from the stress cracks in the flex-plate that caused it to finally break" ? it is quite possible. I remember reading about 2 or 3 that had cracked or broken flex-plates, not as bad as that. In one case it was the cause of his engine tick.

Most converters slide on the spines turn 180 degrees go in and side in some more to seat, this is were most people screw up, they just slide it on and think its seated.

I cant say for sure but I have been told that LR has 3 splines, in other words you have to turn it and lock it a third time. But this is just what i've been told.

 

Thanks! I'll turn it more and put some good pressure on it while turning to be sure it will not click in any further.
I did take your advice and run a long bolt up through one of inspection plate bolt holes to hold it from moving out while I pulled the engine. Thanks for that tip.

 

That thing looks worse than mine when I pulled it. And I let mine rattle for weeks.

 

No idea how long it rattled before it broke but once it did break I bought the truck 3 or 4 days later. I ran it for 30 minutes with it broken completely and no idea how many times he started it after it broke. It is a mess and was fun to get to.
I also made another discovery while doing this, the flywheel on a 4.6 crank is different than a flywheel on a 4.0.
On my 4.0 engine the flywheel bolts onto the crank hub with the 4 bolts that hold the flexplate on and the recessed hex screws hold the hub on. On the 4.6 the flywheel is held onto the crank with the recessed hex screws only.
Weird that it's different. I guess more of their cost cutting?

 

I broke a few in my time when I was 19 years old and did not know anything about a torque wrench.

i think if you torque it wrongly onto the crank shaft it can flex and break.

I think if you torque it wrongly onto the torque converter it can break eventually.

Plus ---
A torque convertor is a rotating mass.
Like a drive shaft - the convertor must be spun and balanced.

i would take the torque convertor to a transmission shop and have then test and balance it.

 

I'll be sure to torque correctly when putting back together.

Good to know. I may do that with the torque converter.
I am kind of concerned that if I pull it out I'll never get it back seated right.

 

Nah.
It will go back in fine.
Pull it out and practice getting it back in fine.
Just put some trans oil into the shaft of the torque convertor and mind the seal that you don't hack that up messing around and you'll be fine.

If your convertor is not balanced that could be a problem.
Look for a weld on the round of the convertor where a weight may have been weld tacked on and fallen off.