zagscrawler Posted October 13, 2013 Share Posted October 13, 2013 Hey all. while doing my 2wd to 4wd convert I am having issues with the new flexplate I am getting from napa. The first one was out of round bad enouph to start to shine the tops of the tight teeth on the ring gear with only about 5 start ups..besides the horrible sound as it was cranked, so after looking at the teeth as the engine was cranked I noticed that the teeth were moving side to side (close then far away from bell housing wall) about an 1/8 of and inch. I removed the trans and flexplate and took it back to napa and picked up a new one. I installed the new one (again) and didn't even connect the converter bolts so I could crank it around again only to find out it was even worse. I mean like this pile of s..t almost scrapes the inside of the bellhousing wall. Almost 3/16 of an inch if I had to say anything. Of course this is reeking havoc on my starter and my knuckles. sooooo has anyone else had these issues or am I missing something when installing these things. The damned thing is indexed so I can only go on one way and has tabs that try to hold the plate centered to the crank flange. I checked for slop with the flange and the flexplate centering tabs and they might move a 1/32 of an inch no where near what I'm seeing at the bell housing.. The only thing I don't know is if the sensor cage that is built into the flexplate moves as much as the ring gear does. The first new plate I installed I actually started up and it ran fine, I'm assuming the cps sensor had no issues picking up breaks in the cage, I am not even going to finish the install on this one so I can't tell if it will run with this flexplate. These are non stock items for my store and this is costing me so much time on a already large project. ANY ideas? Please tell me I'm putting it in wrong lol. At least I can fix it myself then. Thanks guys and gals. Zag Link to comment Share on other sites More sharing options...
jimoshel Posted October 13, 2013 Share Posted October 13, 2013 Any possibility your crank is bent? Leave the plate off and slowly rotate the crank looking for any warpage. Depending on the crank you may be able to attache a dial indicator and check what's happening. Chuck the FW up in a lathe again use the dial indicator. Link to comment Share on other sites More sharing options...
zagscrawler Posted October 13, 2013 Author Share Posted October 13, 2013 my lathe is not large enough to handle that large of diameter part, I would have to go to my pops place and to be honest I don't think it is going to be that critical. There are bigger probs here. no need for indicator imo, I can see the run out with my bare eye lol. Also this truck has been one hell of a trooper with way over 300k miles on it and not once did it ever show any signs this kind of misalignment. No vibrations to speak of with the old set up at all, and with this much of a deflection I would have noticed it with a flywheel as heavy as it was. LoL besides the thing still has the main bearings in it after 300k so I'm sure the crank should be able to handle a little ol flexplate. besides the sound is the first indication that things are not norm. it sounds like my flexplate is eggshaped... To be honest I am going to take a video of the amount of run out with my phone so I have some proof other than my word, if you were to see this $#!& in person you would $#!& a brick. I can believe the starter doesn't stall at the high point its that bad. Link to comment Share on other sites More sharing options...
onlyinajeep726 Posted October 13, 2013 Share Posted October 13, 2013 Make a run out to your nearest junk yard and grab a flex plate from an XJ. As much as you've dropped a tranny by now, you shouldn't be too long out in the yard... haha. Link to comment Share on other sites More sharing options...
zagscrawler Posted October 13, 2013 Author Share Posted October 13, 2013 lol crap ..about an hour ago my wife found a factory flexplate in the garage while we were BBQ'in.. I owe her in a huge way right now. that thing is solid lookin. the crap I have sliced my fingers on today looks so much worse now, what crappy parts those have been. Link to comment Share on other sites More sharing options...
onlyinajeep726 Posted October 13, 2013 Share Posted October 13, 2013 Wish my wife was that helpful when it came to my Jeep addiction haha. I know everyone likes to talk up NAPA like they're the best ever auto store, but even they get Chinese made junk parts from time to time. Probably the case here with your flex plates... Link to comment Share on other sites More sharing options...
Oyaji Posted October 13, 2013 Share Posted October 13, 2013 I have a guess as to the root of the problem - you either got the wrong flexplate or the manufacturer drilled the mounting holes too big. Is there no indexing dowel/rollpin for this application? . If indeed the holes are much bigger than the bolts holding them to the crankshaft, the flexplate could be perfectly machined with so little runout as to be beyond measurement, yet when mounted still be eccentric. Because it hangs from the bolts when you mount it, that eccentricity would be at maximum, too.. . Compare the holes - betcha find them oversize for your crank bolts, and that the flexplate is actually perfectly round after all. Link to comment Share on other sites More sharing options...
zagscrawler Posted October 14, 2013 Author Share Posted October 14, 2013 I wish that was the case man.. Also the flexplate does have centering tabs not aligning pins. Next time you get a chance to check one out look in the center of the plate there are small fingers stamped out and domed slightly that are supposed to ride against the circumference of the machined flange of the crank. I can expect small bits of play here as there was with all the flexplates ive installed lately but the play was no where near the run out I was seeing. Also the indexing I was referring to was the bolt pattern of the crank meaning I could only put the flexplate on in one clocked direction, so like if someone was to say you just need to rotate the plate till it was in the proper holes, I could say I can't rotate it, it only goes on one way... You nailed the fact that the defective plates were infact round but the mounting holes and centering tabs were of to one side, I placed my factory plate on top of the second napa one today and lined up the ring gears till they were totally flush all the way around, which they were, but the center that was stamped out for the mounting was offset. I installed the factory plate earlier today and everything sounds great. I have a video of the run out on my phone now and when I show my buds they all $#!& lol. that's a keeper. The reason I actually took the vid was because when I took the first plate back to the store the counter guy said maybe it was my truck and he was thinking of grabing my returned one for his jeep, I warned him to chuck that piece cause it was all fubared. Hope he believes me. Anyhow I'm sure ill have to show him the vid of the second one to prove I need my damned hard earned money back lol. Thanks for all the advice guys I really appreciate it. this one worked it self out at my shop but I am already having other probs with the convert that I need all the info I can get from anyone :thumbsup: Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 14, 2013 Share Posted October 14, 2013 For a labor intensive products to replace like a flexplate, no way would I mess around with aftermarket junk to save a few $$. You can pickup new Mopar units on Ebay from various Jeep dealerships for less than $70 shipped. It's just not worth it to me. Link to comment Share on other sites More sharing options...
zagscrawler Posted October 15, 2013 Author Share Posted October 15, 2013 That is damned good news to me. I might just get one coming as a back up considering the reputation these things have. Thanks for the heads up. Link to comment Share on other sites More sharing options...
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