Help! '99 Blazer 4WD with loose torque converter - how access bolts?

63vette

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#1
I have a customer who brought me this '99 S-10 Blazer 4WD and 4.3L with over 200K miles. He has had it for about 1 year and supposedly the engine had been rebuilt about 40K miles ago (which I seriously doubt but that doesn't relate to my question). I have yet another instance where Alldata's info doesn't seem to match the vehicle. The customer brought the truck to me because he thought that there was a bearing knock in the engine. The harmonic balancer/pulley has a wobble that I thought was causing the noise - it wasn't an engine bearing knock - it was between a rattle and a knock. I removed the serpentine belt but still the only place I could detect it with a stethoscope was behind the harmonic balancer on the CPS bracket. I was about to replace harmonic balancer but just wasn't convinced that the balancer was causing the noise. I kept poking around and found that the noise was being transmitted through the crank from the torque converter.

A rather lengthy intro to my question which is: how do you access the nuts/bolts that hold the torque converter to the flex plate? The "bell housing has an access hole on the underside that is covered by a round, clip-in plate but no removable cover. I'm am hoping that the answer isn't to pull the starter but that looks like it might be the only access to the flex plate. I've replaced those starters before and they are no fun to get in and out.

To be pointed in the right direction would be GREATLY appreciated! Thank you...Allen
 

63vette

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#3
Thanks for responding Al but as I indicated in my original post, there is no inspection cover. The engine oil pan is a cast aluminum piece that mates up to the transmission case/bellhousing. The only inspection cover is a round hole (less than 2" diameter) at the bottom that is behind the flex plate (no access to the bolts). Further research seems to indicate that the starter opening is the only access to the torque converter bolts - YUK! Also as I said originally, Alldata's info for trans removal and installation doesn't include a single reference to the starter. I wish I could say that this is the first time that Alldata has been useless. $160/month for a one-man-shop is a lot (for me) to pay for "nothing".
 

63vette

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#4
Well, the research was correct...after removing the starter, there is good access to the torque converter bolts. At least we now have a reference here on BAT!
 

billr

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#5
That 2" hole in the back-side, can you see well enough in there to at least tell if there are cracks, or the screws are loose, or the weld-nuts on the flex-plate have come loose? Any chance you could bend a combo-wrench into a "U" shape and get it through that hole and then up onto the screw heads (kind of like a sooper-dooper dizzy wrench).

Edit: OK, ignore that...
 

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#7
@billr: the ring gear is too close to the "bellhousing" to get a wrench on the front of the flex plate. Even if you could, the hole isn't big enough to move the wrench enough to tighten or loosen the bolts. Yes, I was able to VERY slowly turn the flexplate to see that there was some play between the torque converter and the flex plate. On the one bolt/weld-nut that come into view, I could see about one thread of the bolt between the two. And no, unless the crack ran almost to the outside edge of the flex plate, you can't see too much of it.

@al daniels: two of the 3 bolts were loose. I removed them (one-by-one obviously), cleaned the threads, applied medium (blue) Loctite and torqued them to spec (44#'s). I have only briefly started it once so far and the original rattle/knock is gone. I can only hope that the flex plate didn't get hurt.
 
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#8
I had a 95 Chev pickup with the 4L60E that was making a higher pitched knocking sound. I was able to remove my lower bell housing.
But it turned out to me to be the flex Plate was cracked all around the bolt holes where it mates to the crank shaft.

Not too expensive, but you'll need to remove the transmission to replace it.