I have a '99 SD PSD CC 78000 miles I noticed last night on my way home a vibration in the truck. I thought it was just our wonderful PA roads. However this morning on my way in (on a different road) I felt the same thing. It seems to happen when I hit a bump. I tried various things to get it to go away and the only thing that seemed to work was back out of the throttle. It did not seem to happen when I got on the interstate traveling aroung 75 mph.

Anythought on what this could be??? universals in drive shaft maybe????

Thanks in advance

Mike

 

Where do you "feel" this vibration- steering wheel or seat? If in the steering wheel, the problem is most likely in the steering components. If in the seat of your pants, then you should check driveline. Have you checked your tires & shocks?

 

Not in steering. I can't really pin point the vibration it doesn't do it often enough. The whole truck just has a little shutter to it.

I looked at the other threads in this area reguarding vibrations and noises. I checked the driveshaft before I went home last night and it seemed to be just fine.

Could the rears being low in fluid possibly cause this? I have not check the shocks or tires. I am researching lift kits now so I will be putting on new shocks and tires within the next two weeks.(I hope) * 4" lift w/ 35's is my plan *.

Any further comments or questions would be appreciated.

Mike

 

Alright, After driving it for the weekend I think I can explain it a little more.
This vibration is felt through out the truck. (Pass. side, back seat, Console, dash, gas pedal, etc.) I manually take off overdrive no help, I place trans into neutral no help, Hit brakes no help...

HOWEVER WHEN I SHIFT INTO 4X4 THE VIBRATION GOES AWAY...

Does that help anyone out here???

 

So, you hit a "bump" and the truck starts to vibrate. It will only stop when you either a) let off the gas or b) shift to 4WD. The vibration can be felt throughout the truck...

I'd start by checking the transmission mounts. Seem to remember some coming from the factory not completely tightened. You might also check your front hubs to make sure they are completey disengaged or set in the "auto" position.

Just a couple of pure guesses, but they are something to check.

 

Thanks NoMo,
I have some free time tonight I will check on that and post tomorrow.

Mike

 

Thanks NoMo ,

Not only are you a Posting Guru but a genius also. I really appreciate your input on my post. Last night I check the tranny, it was fine, but I also check my hubs, and for some reason my pass side was between auto and lock. God knows how long that has been like that.

Now I was wondering what kind of problems could this have caused, if any??? Do you think I should be conserned???? Also when I went to check the hubs I could not move it either way so I had to use a pair of pliers. It was still very hard but I mannaged to get it to move. I sprayed WD-40 in it and now it moves just fine. The drive side was tough also but it moved by hand so I also WD-40'd it.

 

That was outstanding NoMo. I would not call that a guess, I would call that an educated input to resolve a problem. I am very impressed.

Mike, I am wondering if you shouldn't flush the gear oil in your front diff. Could the partially engaged hub caused some wear on the gears thus causing some metal shavings in the diff? I am not a mechanic by any stretch but seems like a relatively safe insurance policy.

 

Unless your a real stickler, I wouldn't worry about the fluid. Lots of guys here drive around all winter with the hubs engaged.

The hubs are pretty much locked or unlocked, there isn't really an in between or "partially" locked.

They do tend to stick in the locked position, whether manual or auto.

The WD 40 trick will work a couple of times, but the real solution is to take the hubs off, clean them, and lube them properly. You may also want to check the vacuum line to that hub if you have the ESOF system, although most likely the hub was too stiff for the vacuum to overcome.

Good work NoMo, it was really hard to tell until he mentioned that the vibration went away in 4X4, then I figured you were on the right track with a sticking hub.

Glad your up and truckin' again 99sdpstd!

Waxy

 

Thanks, but the real key to guessing about the hubs was the 4x4 "cure" that was found. I guess the real question is whether the problem is truely fixed or not.

As for running with the hub engaged, I'm with Waxy. No need to change anything unless you are just about to a scheduled maintenance point anyway. I would, however, recommend a monthly "manual" locking of the hubs, drive a few miles, then unlock them. This will serve two functions: You'll keep the front axles lubed and you will keep the hubs from sticking so bad you have to use pliers. At the very least, you'll want to add a hub-check to your fuel station routine. You know, fill with gas, check the oil, kick the tires, eyeball the hubs, etc.

 

Guys I truely appreciate your input. The problems has now been fixed for 24 hours with about 200 mile and I have yet felt that vibration. (THANKS TO NoMo)
Sorry it took so long to figure it out that it went away when I went into 4x4 but I was trying to eliminate one thing at a time and to my surprise shifting into 4x4 and presto it was gone. I am glad though that when I posted that finding NoMo gave me the right area to look. I was deathly afraid maybe front rear, axles or what ever.
I know one thing for sure I wont do a darn thing to my truck without checking with you guys first.

Hey NoMo this is the last time I am going to kiss your a$$ and thank you for viewing my post and giving me a great idea, which fixed my prob.

THANK YOU!!!!!

Mike

Oh yea I also have a question about lift kits but I will start another thread. I am sure DC special will be all over that I see him reply to alot of lift questions. He seems to really know his sh**.

Waxy thanks for your input also I am definately going to lube my hubs this weekend.

 

Partial quote above

Hey Waxy/NoMo,

I haven't had the problem since we last talked. However we were blessed with 4 inches of snow yesterday and to move my truck around at the shop I used 4 wheel drive to get up the hill. Yep, you guessed it. On the way home last night I hit yet another bump in our wonderful PA roads and the vibration returned. Waxy you stated something about a vacuum line for the ESOF system. Is it posible for you to be a little more detailed as to what I am looking for and what to do once I find it???
I always thought your hubs were locked or not locked this "auto" stuff kind of confussed me. Why not just put the lever on the floor like I had in my '97 F150?? It was still SOF.
Sorry for being long winded. Bad weather expected all week I hope to get a chance tomorrow night to look at it.

Thanks in advance,
Mike

 

The vacuum line is a thin black hose, kinda like a fuel line, that runs from your hub up to a connection point at the solenoid on the passenger side behind the battery. I don't have a picture of the hub, but check out Stan Wright's article on this (and a ton of other good info on the SD) at

http://www.eurekaboy.com/f250/esof.htm

Check the line for any sign of cracking or leaks, if the line is OK, then it may be the seals inside the hub itself. My suggestion would be to take the hubs apart, clean them, and give them a light coat of grease. This will make them easier to lock/unlock, and should really help the performance of the vacuum actuation. I'd suggest picking yourself up a cheap Haynes (or the equivalent) service manual to help guide you through it, it's a good investment.

Depending on the miles and useage you have on your truck, it may not be a bad idea to replace the rubber seals while you're in there, it's cheap insurance.

I haven't torn into the hubs on my SD yet, so I can't be a whole lot more specific than that, but someone else will likely be able to answer your questions if you get stuck.

Quote:

Why not just put the lever on the floor like I had in my '97 F150?? It was still SOF.

Careful, that's a loaded question around here.

The ESOF gives you the best of both worlds IMHO, you can flip the switch or you can get out and manually lock the hubs like you did on your '97 and use the switch the same way you used the lever. The ESOF is a "convenience", but it has a built in fail safe in case you need it. Either way works.

Unfortunately, sticking hubs is not uncommon, I've had manual hubs that were a bear to unlock too.

Waxy

 

Thanks Waxy,

I tried to post earlier but server was down I guess?

Thank you for the link I spent alot of time there today. That guy was loaded with info and very descriptive.

I will get some time this weekend and try some additional things. ie locate the vacuum line, take apart hub and lightly greese etc... I will post my findings and results. Thanks for now.

Mike