I have a 94 f150 4.9 4x4 with a m5r2 and a bw1356. I have a vibration that causes the whole truck to shake it lightly starts in 1st and 2nd but in 3rd it shakes more with a valve rattle or loose chain coming from the floor around transmission an transfer case location. When I shift to 4th around 45mph the vibration is worse an the rattle is loud an a growl starts. If I shift to 5th the growl gets loud but the rattle lessons an the vibration gets worse with the speedometer bounces around 10 mph up an down but I stay steady speed. If I slow down without down shifting the rattle is extremely bad as like something os coming apart if I pop the clutch it completely stops if I'm driving. The ujoints on the rear is brand new. Fluid in diff an transmission is new an clean. I found the pink milkshake in the transfer case knowing that was water in there I changed it out with clean ran for a day the flushed with diesel fuel several times then added fresh fluid in it. This is happing in 2 wheel drive I haven't tried 4 wheel and front hubs aren't locked need help asap thanks

 

Welcome to FTE.

You need to take that all apart and look for cracks, breaks, bearing failure, u-joint failure and phasing, drive shaft bend, mounts bent or broken, transmission, clutch, etc issues.

Stop driving it till you can take it apart.

 

What exactly do I need to take apart? Ujoints are new drive shaft is fine mounts look good still I'm trying to find the exact problem I don't want to play a guessing game I did that when I first got the truck I listen to 10 people an changed all the parts they said after 2000$ in I found that the fuel regulator was bad a 15$ part so I'm now playing with drive train I don't want to just start replacing things I don't need because it's way more money involved now

 

When I first got my truck it too had a hard buck. I removed the inspection cover on the drivetrain and realized that I only had one bolt, where there should have been 6 or 4, I can't remember exactly, left connecting the flywheel to the converter. I added aircraft grade bolts and red loctite and no problems since.
Now, you can't come on here and do a write up and expect anybody to be able to diagnose your problem sight unseen then get pissy about it. All we can do is give you our best guesses and past experiences then you have to figure out if that's your problem or not. Of that $2000, did you test the parts before buying new and replacing. Not our faults if you just threw money at it.

Take it to a mechanic,... that's the only suggestions that you will get with this attitude

 

Just for your information I didnt get mad nor pissy at all I was just asking simple questions so if you thought I got mad or had a attitude I think it's you that has the problem I'm still not even mad or have a attitude lol I think that was funny you thought so actually. But I dought that's my problem thanks for the help I don't have a torque converter bud. I know people will do there best an have guesses an I appreciate that they do no harm no foul because either way it's my choice to replace or not. An no I didn't test them because I have not mess with fuel injection until I got this truck so now I have more wisdom an knowledge into diagnosing the electronics of fuel injection system buddy

 

I didn't take it as being mad, just frustrated, which is understandable. Sometimes things don't translate well on the internet.

It sounds like already have, but definitely comb everything over to be sure that there are no broken bolts, transmission mounts, engine mounts, that sort of thing.

A U-Joint would only cause an issue when you're NOT accelerating, since the engine would otherwise apply pressure/torque that would keep it from wobbling.

As 85e150 said, check your driveline phasing. If it's out of phase, that'll really shake your truck.



When Carloespo was talking about the flywheel, he wasn't suggesting you have an automatic or torque converter, but the idea that your flywheel may have bolts out, which would cause it to be out of balance.

Another issue would be if someone used the wrong flywheel, like one from a V8 which is not balanced the same way.

If you want to eliminate the rear end as a potential, remove your rear driveshaft from the vehicle completely, and then drive around in 4x4 (essentially like a front wheel drive truck). See if it still rattles / vibrates.

You should also post your issue over in the driveline forum, since this does not necessarily sound like it is specifically 300 inline six related. Get some more eyes on it.

Clutch, Transmission, Differential, Axle & Transfer Case - Ford Truck Enthusiasts Forums

 

See the red posts
Dave ----

 

hey guy update just found out the issue but first I want to thank everyone for there answers an help I deeply appreciate everything an the help I wasn't mad at anyone on here also was little frustrated about the truck not towards y'all. Anyways I found out u bolts that hold the axle to the leaf springs are lose as hell I think I may also have snapped a pin in the lift blocks unsure right now but again thank you for all the help everyone. If y'all need help if I can help give me a message I'll do my best thanks again.

 

Good to hear you found something and before it get really bad and lost control of the truck.
Dave ----

 

Thanks for the update on your issues, much appreciated! And definitely glad you figured it out. That sounds like it could have gotten dangerous.

And FuzzFace, you're correct on the U-bolts. I was actually thinking about a bad slip joint in the driveshaft. It's been about 10 years since I fixed all of that stuff and I was getting them mixed.

 

Not a big deal if you have not dealt with this much you do forget about it.
I have never had to deal with a bad slip joint so would not how it would show up till then.
As long as the information is out there so if someone searches they find it.
Dave ----