Starter can't engage flex plate

[TheDWord]

I have an interesting one!

I've working on getting my 2001 TJ 4.0 Automatic back to a respectable running state, and having a nightmare of a time with it. Check this thread if you're interested in more detail on that - https://wranglertjforum.com/threads/yet-another-misfire.59466/

I just grabbed and swapped in a long block from a 2006 with like 60k (super clean motor!). After getting it started up I had reason to believe the flex plate was bad, so I went about dropping the transmission and replacing that. After getting everything buttoned up, I was able to start the engine a couple times, noticed a small issue that needed fixed. I corrected that issue and haven't been able to start since.

The starter receives power pops the bendix and gears on the flex plate and starter just touch and grind. I've tried 2 different parts store starters and an OEM one from the junk yard, they all are doing the same thing. From what I can tell, it appears the starter is about 3/8" too shallow. I think the couple times I've been able to start it I was just lucky enough to catch enough of the flex plate to get good rotation.

Anyone have any thoughts on what might be happening here and how to correct it?

 

[TheDWord]

Seems I goofed when putting the transmission back in. On another forum I saw a comment about a shop possibly using the flex plate to converter bolts to pull the parts together, apparently that's a no-no and appears to be what I did. I backed out those 4 bolts to finger tight and gave them just a couple tightening turns. With that, the engine fired right up. I have some noise coming from the bell housing (I'm guessing the crank sensor?) and seems the shifter linkage needs some adjustment.

Guess I have some reading to do on proper installation procedure.

 

[BabyBass2]

Seems like a depht issue. A bit of “too much distance” from the starter gear to the ring will do that. The starter is designed to first move forward and only start turning when it reaches its full sprocket forward motion, this trick is done by the solenoid internal mechanics, if you open one, you will see that the solenoid-starter electrical contacts inside the solenoid, make contact “at the end of the solenoid mechanical motion so the starter won’t turn until is fully engaged too the ring ( the solenoid is a very wise design ). If it is to far from the ring, it will start rotating before engaging the ring and you will get that awful grinding noise and no engine turning. Measure, measure, measure, thats the trick. Try to find a friend with an automatic that is dissasembled and find its distances. There are longer starters with deeper sprocket reach, perhaps you have got the wrong starter part number also, try comparing starter sizes, I mean, sprocket to starter mount lenght, this might be the issue, wrong starter for your install.

 

[Fishtaco]

Seems like a depht issue. A bit of “too much distance” from the starter gear to the ring will do that. The starter is designed to first move forward and only start turning when it reaches its full sprocket forward motion, this trick is done by the solenoid internal mechanics, if you open one, you will see that the solenoid-starter electrical contacts inside the solenoid, make contact “at the end of the solenoid mechanical motion so the starter won’t turn until is fully engaged too the ring ( the solenoid is a very wise design ). If it is to far from the ring, it will start rotating before engaging the ring and you will get that awful grinding noise and no engine turning. Measure, measure, measure, thats the trick. Try to find a friend with an automatic that is dissasembled and find its distances. There are longer starters with deeper sprocket reach, perhaps you have got the wrong starter part number also, try comparing starter sizes, I mean, sprocket to starter mount lenght, this might be the issue, wrong starter for your install.

So if you engage a starter Bendix when out of the vehicle why does it throw out and spin from the worm drive from first power contact ?
unless I am on another planet the Bendix spins as soon as its given power from the solenoid so much so you have trouble holding a starter.

Just asking not telling

 

[BabyBass2]

I have an interesting one!

I've working on getting my 2001 TJ 4.0 Automatic back to a respectable running state, and having a nightmare of a time with it. Check this thread if you're interested in more detail on that - https://wranglertjforum.com/threads/yet-another-misfire.59466/

I just grabbed and swapped in a long block from a 2006 with like 60k (super clean motor!). After getting it started up I had reason to believe the flex plate was bad, so I went about dropping the transmission and replacing that. After getting everything buttoned up, I was able to start the engine a couple times, noticed a small issue that needed fixed. I corrected that issue and haven't been able to start since.

The starter receives power pops the bendix and gears on the flex plate and starter just touch and grind. I've tried 2 different parts store starters and an OEM one from the junk yard, they all are doing the same thing. From what I can tell, it appears the starter is about 3/8" too shallow. I think the couple times I've been able to start it I was just lucky enough to catch enough of the flex plate to get good rotation.

Anyone have any thoughts on what might be happening here and how to correct it?

Another thing is the year, sometimes the changes in parts between years are so minute that are hard to see. You said you installed a different engine, probably from a different factory altogether. Its all in the measurements, I would start measuring things.

 

[Old_Crow]

Sounds like you shoved the converter all the way into the transmission when you installed it and then used the bolts through the flex plate to try and pull the converter back to its normal position. If you tightened the bolts one at a time, you probably put a bind on the converter, which caused the flex plate to, well, flex instead of actually pulling the converter out of the trans. When you loosened the bolts and rotated the flywheel/flex plate assembly, you likely eased the bind and the converter moved into position correctly. IIRC, the snout of the converter is a snug fit into the back of the crank, and that's likely where the binding was.

 

[TheDWord]

Turns out, in my excitement to get the engine in I didn't fully review the documentation from the wrecker and failed to note the motor was from a manual vehicle. On top of that, my inexperience swapping engines allowed me to miss the pilot bearing in the crank.

Removed (hammered, drilled, chiseled... destroyed) the pilot bearing from the crank and everything went together perfectly!

 

[BabyBass2]

Turns out, in my excitement to get the engine in I didn't fully review the documentation from the wrecker and failed to note the motor was from a manual vehicle. On top of that, my inexperience swapping engines allowed me to miss the pilot bearing in the crank.

Removed (hammered, drilled, chiseled... destroyed) the pilot bearing from the crank and everything went together perfectly!

Congrats !!! I am so glad !!! This hobby is like solving a “Rubics Cube“ !!!, to make a change and succeed you have to go through weird movements. If you do this every day for years, you will master it just to figure out that every day and mod or fix is a new thing you have never seen before !!! We write in this Forums with questions, and the answers and solutions pop up, and stay for others to use. Thanks for sharing your findings. Now about the late pilot-bearing, and its final destiny....... thats a funny story !!! I can picture you all so eager to pull it out of there, total madness ????

 

[TheDWord]

There are so many things that the service manuals just don't tell you, and can't anticipate! The forums are a wealth of information, you would think that all of these scenario's have come up many times over considering the age of our Jeeps, but here we are. LOL I know this experience is going to help me in future projects, but I hope it can save someone else some headache too.

Here's the final condition of the pilot bearing. Tried the bread trick, didn't budge. Tried a pilot bearing puller, didn't budge. Ended up getting a drill, chisel, large screwdriver and BFH out to encourage the removal. Can't believe this little bugger was holding me back for days!

 

[TNHEADDUCK]

There are so many things that the service manuals just don't tell you, and can't anticipate! The forums are a wealth of information, you would think that all of these scenario's have come up many times over considering the age of our Jeeps, but here we are. LOL I know this experience is going to help me in future projects, but I hope it can save someone else some headache too.

Here's the final condition of the pilot bearing. Tried the bread trick, didn't budge. Tried a pilot bearing puller, didn't budge. Ended up getting a drill, chisel, large screwdriver and BFH out to encourage the removal. Can't believe this little bugger was holding me back for days!

View attachment 323517

Wet toilet paper or paper towel always worked for me, It will hold a lot more than you think behind the bearing. But simple hydraulics works in the end.

 

[SlipJoint]

There are so many things that the service manuals just don't tell you, and can't anticipate! The forums are a wealth of information, you would think that all of these scenario's have come up many times over considering the age of our Jeeps, but here we are. LOL I know this experience is going to help me in future projects, but I hope it can save someone else some headache too.

Here's the final condition of the pilot bearing. Tried the bread trick, didn't budge. Tried a pilot bearing puller, didn't budge. Ended up getting a drill, chisel, large screwdriver and BFH out to encourage the removal. Can't believe this little bugger was holding me back for days!

View attachment 323517

Wish Had found this thread 2 days ago. I did the same exact thing. I guess it's time to pull the transmission. Thanks