DanMan2k06
NAXJA Forum User
- Location
- Damascus, MD
1998 - AW4 - 231 - 90,000 miles - Ok here's the scoop. Picked up a new Jeep super cheap from a small up and coming shop that seemed to be cherokee enthusiasts. When I bought it, the seller told/showed me there was a noise, and leaned REALLY hard towards a cracked flexplate or something transmission related.
Got the Jeep home, started it up, and the noise sounded EXACTLY like serious rod knock. Towards the back on the block, so maybe it was the TC bolts or a crack? Or cylinder(s) 5/6 knocking? Checked all the TC bolts, tight. Checked for any cracks, couldn't see anything. Did some basic engine diag and came up empty handed. So I dropped the oil pan and all the bearings, looking for any destructive evidence. With such low mileage I found it hard to believe something engine related would have gone wrong so soon. Reassuringly, everything on the bottom end was fine.
Decided to pull the trans. One that was out I could see the the flexplate was not only cracked, but it was completely broken. The center section that bolts to the crank had completely broken away from the remaining part of the flexplate. I've never seen this. I'll get a pic soon.
Got a new flex plate and threw it in. Along with all new bolts, and a new spacers that sits in front of the flexplate. Now when I start the jeep, there's a horrid noise of the starter skipping teeth on the flexplate. With someone under the jeep and the cover off, we can see that the flex plate isn't spinning true. It's "wobbling", like too much runout. When a certain part of the plate gets around the the starter, there's not enough engagement to keep it moving and the starter skips. I figured maybe the shaft on the TC is bent, causing the flexplate to also bend. So I disconnected the torque converter bolts, and pulled the injector plugs so the jeep wouldn't start. The flexplate is still spinning crooked, and still skipping teeth. Could I have gotten a warped flexplate from the get-go? Could the end of the crank be warped? The palte was seated and torqued properly. It's a rock auto special, so I was weary from the start.
Got the Jeep home, started it up, and the noise sounded EXACTLY like serious rod knock. Towards the back on the block, so maybe it was the TC bolts or a crack? Or cylinder(s) 5/6 knocking? Checked all the TC bolts, tight. Checked for any cracks, couldn't see anything. Did some basic engine diag and came up empty handed. So I dropped the oil pan and all the bearings, looking for any destructive evidence. With such low mileage I found it hard to believe something engine related would have gone wrong so soon. Reassuringly, everything on the bottom end was fine.
Decided to pull the trans. One that was out I could see the the flexplate was not only cracked, but it was completely broken. The center section that bolts to the crank had completely broken away from the remaining part of the flexplate. I've never seen this. I'll get a pic soon.
Got a new flex plate and threw it in. Along with all new bolts, and a new spacers that sits in front of the flexplate. Now when I start the jeep, there's a horrid noise of the starter skipping teeth on the flexplate. With someone under the jeep and the cover off, we can see that the flex plate isn't spinning true. It's "wobbling", like too much runout. When a certain part of the plate gets around the the starter, there's not enough engagement to keep it moving and the starter skips. I figured maybe the shaft on the TC is bent, causing the flexplate to also bend. So I disconnected the torque converter bolts, and pulled the injector plugs so the jeep wouldn't start. The flexplate is still spinning crooked, and still skipping teeth. Could I have gotten a warped flexplate from the get-go? Could the end of the crank be warped? The palte was seated and torqued properly. It's a rock auto special, so I was weary from the start.