Flexplate & Torque Converter problems...need some advise and referrals on this one..

[Asmoday]

Flexplate & Torque Converter problems...need some advise and referrals on this one..

Hello All,

I have been noticing a weird rattling sound developing over the last month or so on the M1009 and finally had some time to get under her today to see whats up. I had read all the posts about torque converter bolts loosening up on the flexplate and a little voice was telling me to check them. It was a bit of a pain to get the bell housing cover off because the trans cooler lines were not co-operating since some idiot had rounded the flare fittings a bit. No...it wasn't me who rounded them.

Nonetheless once I started checking the bolts I found all but two of the bolts barely wrist tight...! Now what really pisses me off about this is that when I bought the truck the transmission had just been swapped by someone I believed had done it correctly and since I've only put about 3,000 mi on the truck so far I did NOT expect any loose bolts.

Upon removing each bolt it was obvious that no loctite was used on any of them. I pulled out the TM's and found the appropriate section for the torque spec. on the bolts which is listed as 50 ft/lbs. (68 N.m).

I marked all the bolt locations and removed each bolt, cleaned and reinstalled with loctite 243 and then torqued to spec. doing each bolt in a crisscross pattern. Everything went well until the last two needed to be done. Both bolts stripped out at around 30 ft/lbs.

I determined that the bolt threads were fine but the torque converter threaded bosses themselves stripped out. I wrapped each bolt with a thin aluminum sheet shim, added loctite and then reinstalled for now. I was able to get them pretty snug but obviously not to spec and this is only temporary. I stated her up and the majority of the rattling noise is gone but some still remains.

I was planning on replacing the torque converter and flexplate when I get the trans rebuilt....just not yet...
I do have a NOS flexplate put away at least.

My main questions...

Can I still drive it for now until I line up a viable shop to do the trans rebuild or is this a no no?

I know this is a loaded question but who's making the HD best torque converters these days for our M1009's? I'll pay for quality.

Can someone in the Los Angeles ares recommend a viable trans shop who can do a nice rebuild? I have not had good luck through the years with trans shops.

Should I add any special upgrades for the rebuild?

Thanks guys....I'm bummin'...

 

[Skinny]

I would go about it a few different ways.

One, if you want to salvage what you have...I would helicoil what you have. Since the TH400 converter in this application is a non-lockup, you can't do too much damage to it other than puncturing the metal and letting ATF come out. If it was a lock up converter, you could risk dimpling the front side of the housing which will destroy the clutch. In this case, hammer away. If you don't want to go that step, try tapping whatever threads are left and assembly using red loctite. It will hold like a weld but be prepared to impact it trying to get it apart again. I think it would hold with red if there is any bit of thread left.

Two, pull the converter out and have a trans shop that rebuilds converters weld new bungs or repair yours. The only thing that can fail in a CUCV converter is the stator bearing or something physically coming undone. That's it! Fix what you have.

If I was in your shoes, I would red loctite it and run it till it goes.

 

[V8Astro]

^what he said

 

[Asmoday]

Skinny...Thanks for the advice! Late last night I pretty much came to the same conclusion.

Now...what's the best way to get in there and helicoil the torque converter lugs while it's still installed? I really don't want to have to pull the trans since it's way beyond my capability at this time. Where would the most room for access be in there? I basically re-torqued all the bolts at the starter side area but I'm wondering if I remove the oil filter maybe I'll have room to get a 90 degree drill in there with a short bit or maybe I should just remove the starter and go in there?

The threads on the two bad lugs are pretty well stripped preventing any real torque spec. so I will definitely have to use helicoils. Now I'm wondering if I should redo all of them with red Loctite...opinions?

I confirmed the torque spec. listed in the TM is 50 foot-pounds. Does this sound correct to everyone as I have read on some diesel web sites that 35-40 foot-pounds is recommended for the 6.2? I would think the lugs with the 10mm bolts should torque to 50 though.

Do you all think it will be OK to drive right now until I can get to it in a couple of weeks? The bad bolts were snugged up pretty good with Loctite 243. I wouldn't think they would back out short term.

Thanks...

 

[scottladdy]

I don't know if it will be OK to operate your truck in the current condition. I will say, if it was mine I would not do so. Just what I would do.

I hope this helps ...

 

[Asmoday]

Hmmm....what to do.

Plus I'm trying to figure out how to get in there to drill and tap the bad lugs...

 

[Barrman]

I think if you remove the starter motor and postition the one you want to work on over there. You should be able to get better access. I just looked at an engine here in my class and you will have about 1-2 inches of room away from the pan and as far forward as the motor mount to get a drill in there. An angle drill would do it without issue. An air angle drill will make the job easy. As far as putting the heilicoil in. Get an 8 point socket for square head bolts and run the tap with that.

 

[Skinny]

Yes, what Barrman said.

Also be sure to inspect either with a mirror or video bore scope the center hub area of the flexplate because that is also a common place for it to crack as well.

 

[Asmoday]

Ok...will do. Thanks guys... I did look it over best I could for cracks but I'll give it a second go over during repairs.

Now...My main concern is how am I going to line the drill up in there to get the hole drilled straight and correct? Does anyone have any suggestions, tips, etc.? It's gonna be an awkward area work in from the get go and I've been racking my brain trying to figure out the best way to get the hole drilled straight for the helicoil tap.

A A&P mechanic friend from work did comment that if the hole was already completely stripped out that I may not even need to drill it....maybe just go ahead and run the helicoil bottom tap on the hole. What do you guys think?

Thanks!

 

[scottladdy]

Don't you need about the same amount of clearance to drill the hole as to run the tap? I'd hate to see you snap a hardened tap off in a slightly undersized hole. Now that would be a bear to fix ...

 

[Asmoday]

Yes...that's true. I have a couple really nice shorty drill bits coming for the job so I'll drill them. I'm just concerned with how I'm gonna drill the holes straight...

 

[scottladdy]

berry berry caiwfuwee!!