Jstihl, I know this is a holiday week and you only took the truck in on Monday, but did you hear anything from them or did they say when they thought they could get to looking at it?

You are very wise to set out a course of action in case you find out it is the flex plate. You will have part numbers and sources ready instead of researching and taking more time.

I don't know if I want to hope this is the problem or not... If it is, great! You can get it fixed... If it is not, great! You don't have to spend $1000 to fix it, but you are stuck trying to figure it out.

 

Hey Sous, thank you for following up I have been meaning to update. The truck is at a local trans shop and initially the mechanic said he thought there was nothing wrong when he drove the truck but when I told him the truck ran fine he had to go under the truck to listen in the tourqe converter area with the inspection plate removed he then agreed with me that the trans needed further inspection. I have listened to all the you tube videos that have to do with broken flexplates and though my situation is not as bad as many of those there are a few that sound exactly what my truck sounds like. There have been several threads that I have found that fit my symptoms to a tee. There is a grinding sound in park and neutral and as soon as the rpms are raised the sound and vibration goes away. There also seems to be a uneven load being put on the engine which I think is where my idle surging was coming from. At this point all I can do is have the mechanic remove the trans to see if there is anything wrong. Being that he did such a good job on my f450 I am having him go through the trans and upgrading everything that needs it while it is out.

This is a big gamble in hopes of solving my problems especially the vibration at idle. My question to you gurus is it safe to remove the trans and run the truck with no load on a lift? I think if the problems still persist at this time I may be looking at the crank which would be heart breaking.

Trans guy is a one man band and very thorough , he will be starting at some point this coming week. At this point I am hoping and praying the trans is the problem even though it may cost a pretty penny , I am hoping for some closure to this issue..... I said the same thing right before I bit the bullet on new injectors

 

I see no problem running the engine without tranny,just dont rev it too much..Should spin pretty easy with no drivetrain..

 

I agree with our friend from Finland. I think jdeshler had his engine running sitting on a crate outside of the truck in this thread. I might be remembering another teardown thread though.

 

Great, thanks guys, if there are not any obvious signs of something wrong when he pulls the transmission I will have him run it

 

I like this clip.
No turbo with headers and cammed..

 

Hey guys just wanted to give a update. Trans guy finally got the tranny out and tore apart today. Turns out the guy I bought the truck from pretty much fixed the transmission enough to sell it. He said there was alot of red flags In there. Clutches 2 and 3 were on their way out and the accumulator springs were all bent up and warped. He thinks they did not put in a billet tourqe converter which might have been the grinding noise I was hearing. He showed me all the bad parts and also showed me alot of the upgraded parts that he puts in these 4r100's. Truthfully alot if it i didn't understand being that I know hardly anything about automatic transmissions but he seems to do a really good job. He rebuilt the tranny on my f450 and I haul a ton of weight with that, still going strong. He said the flex plate still looked okay. Is it possible to pull the tranny without pulling out the flex plate? He acted like it was still in the truck so I wasn't sure. I was really hoping for a definitive answer like a bad torque converter or broken flex plate that might be causing my vibration but at least I know that it wasn't all for nothing being that all this was going to need to be done soon anyways. will let you guys know how it runs once I get the truck back

 

It's a direction at least right, and it's only money. Oh how these trucks luuuuv money.

 

Another option is having your mechanic change the flex plate/flywheel anyway since he is right there. You have spent a lot of time and money chasing this issue down. So, the question is do you want to be sure for ~$200 more or hope that you are making the right decision?

That is what it boils down to good sir and only you know what is in your heart and mind.

https://www.riffraffdiesel.com/flex-...el-7-3l-94-03/

 

Converter has to be unbolted from the flexplate,before tranny can go out.Flexplate is bolted on the crankshaft.

 

Thanks guys, turns out the flywheel was still on the truck but he took it out and it didn't have any cracks. Didn't know if there was any way the flex plate may have been unbalanced or something so I am overnighting a new flex plate from riffraff anyways just to be on the safe side. At least now I will definitely know there is nothing from the transmission causing any of these problems. hoping to have the truck back on Friday so I will report back then. Crossing fingers 😬😬😬

 

That was a wise call in my opinion and I would have done the same thing.

I really hope you have a smooth running truck at the end of the week.

 

Well I got the truck back yesterday and when I first fired it up it ran nice and smooth with just a slight vibration, I thought well I can live with that the truck ran more quiet without that odd vibration sound in the front..... After about 10-15 minutes of driving it was back to vibrating just like it was 🤬. I can't think of anything that would cause this to be intermittent, all he did was pull the tranny. This isn't the first time this has happened though. It's like the PCM is commanding something on to make the vibration. It's also back to surging up and down from 760 - 704. Try disconnecting the batteries overnight to see if it ran smooth this morning but that didn't work. I'm at a loss, the truck runs great other than at idle. Super bummed out but the truck shifts and drives much better now. If there is any silver lining I guess it's better that I got the transmission rebuilt now than being stuck on the side of the road....

 

On another note, I found out that someone replaced the passenger side battery ground cable with a single alternator version. The battery cable is too short so it rubs really tight against the lower alternator and has worn away some of the insulation which I tried to put electrical tape on. Motorcraft has discontinued this cable and you can't find it anywhere but I did find one company that makes them with the correct fittings ,which I ordered. I don't know if this would be the cause of any of my problems but it definitely can't be good with all the heat generated from the alternator and the insulation somewhat worn away. Took me forever to figure out that there is a different cable for dual alternators, the one that's on my truck looks like a factory cable but always thought it was way too short as it barely reaches the battery post. Here is a link to the part if anyone needs it for dual alts. It is way overpriced but I didn't feel like getting the parts and making my own as I have so many other things I'm trying to deal with on this truck. Notice the different cable end that attaches to the block next to the lower alternator.
https://www.npdlink.com/product/cabl...y/128569/70254

 

If I may suggest trying to track down the 1105 and 1106 DTC's and HOPEFULLY that will either fix the issue or lead you to the true issue. Like you said, the truck shifts and drives much better now and you can continue your journey to identify the true issue. Sometimes things do not work out the way we wanted them to or hoped they would, but it is a good quality for a person to have to find that silver lining.

You are wise to replace that negative cable, just one more box ticked off the checklist.

As you work your way through the checklist, keep us all in the loop. We are here for support in anyway we can and many of us are hoping you find the issue soon.