High 3rd gear, low 4th gear vibration (2 Viewers)

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Aha interesting. So you get it both on the gas and off the gas, and cruising at 40 (?), but not with the clutch pushed in.

I see a drop off fluid on the transfer drain plug - all your fluids are topped up I assume? (Gearbox, transfer, differentials).
Probably a bad assumption! Yes I saw the drop there too, I'll check those ASAP...
 
Probably a bad assumption! Yes I saw the drop there too, I'll check those ASAP...
Its a fairly short aluminium thread on the drain, so don't be tempted to swing on the wrench to stop the leak. Might need a new crush washer.
Open the fill plug and see how much you can add.
 
Its a fairly short aluminium thread on the drain, so don't be tempted to swing on the wrench to stop the leak. Might need a new crush washer.
Open the fill plug and see how much you can add.
Thank you, I appreciate the advice, it'll be good to get that leak stopped. I think I ordered a half dozen crush washers for my oil plug but I'm sure I won't be that lucky they'll match; as soon as I get home I'll check it.
 
I watched a vid on a f150 a few days ago. He have vibrations in a certain speed range. One u-joint was bad on one cap and a few other sides were worn. New u-joint, no more vibs. And I have seen issues with the shaft half pumped full of grease - it can settle on one side.

I still vote for hands on with an "experienced" car person.
 
Thank you, I appreciate the advice, it'll be good to get that leak stopped. I think I ordered a half dozen crush washers for my oil plug but I'm sure I won't be that lucky they'll match; as soon as I get home I'll check it.
Should be the same M18 thread I think. If you find it stripped beyond use then I'll point you to my recent helicoil repair on the same hole ;)
 
Has the OP gone to the clubhouse section and posted locally to see if someone local can lend him a hand in diagnosing what the issue might be?
 
I watched a vid on a f150 a few days ago. He have vibrations in a certain speed range. One u-joint was bad on one cap and a few other sides were worn. New u-joint, no more vibs. And I have seen issues with the shaft half pumped full of grease - it can settle on one side.

I still vote for hands on with an "experienced" car person.
My usual guy who has a shop behind his house is very good but covered up that any help from him is months away. I'm going to try the things within my reach like fluids and lube any anything you guys think I can swing but I do intend on getting on his books for some suspension work and shims, if it's still vibrating like crazy hopefully he can get it handled.
 
What you are describing is ujoint(s) that are toast. Replace your U-Joints and I bet your issue goes away. BTDT twice.
Why does it go away when the clutch is disengaged?

OP has seen slight improvement after greasing the front one - not greased the rear yet - is that consistent with your expectations?
 
Why does it go away when the clutch is disengaged?

OP has seen slight improvement after greasing the front one - not greased the rear yet - is that consistent with your expectations?

It goes away because there is no load on the u-joint with the clutch pushed in.
 
For anyone still wondering about this, I have a bit of an update -

The vibration got significantly worse recently, to the point it started making a high speed grinding sound intermittently. When I was driving it home from getting a new gas tank put in, as I turned the corner on my street 3rd gear "slipped" - it was in gear and not doing anything. The mechanic who swore up and down that it was just a flat spot on the tires recanted and said that it might be the syncros on the transmission going out.

At this point I'm scared to drive it, so I'm going to tow it to a shop and and get a new (used) transmission put in (or have it rebuilt if it's an option?) and then have the clutch done while it's ripped apart.
 
It drives normally in other gears now but not in 3rd?

Synchros tend to create a lot of gold flecks when they break up so you'll know right away when you drain the gearbox oil.

Surprised that it was changing gear smoothly before though if that's the case.

You sure your transfer is fully engaged in 2H?
 
It drives normally in other gears now but not in 3rd?

Synchros tend to create a lot of gold flecks when they break up so you'll know right away when you drain the gearbox oil.

Surprised that it was changing gear smoothly before though if that's the case.

You sure your transfer is fully engaged in 2H?
1st and second gear are buttery smooth - if I wind 2nd gear higher than I should (where I should be in 3rd already) it starts to vibrate some, but it only gets REALLY bad in the middle / high end of third and the begining of 4th. Once I pick up a sufficient amount of speed in 4th, it goes away as well - or it used to; now it does the roaring thing.

I can stick my finger in the transmission fill hole and see if there are any gold flecks - or should I just go ahead and drain it and check that way?

As far as being sure about the transfer being fully 2H, I honestly didn't think to check that. I'll go mash on it and see if it is hanging halfway or something...

Edit: As best I can tell it's properly in 2H - I put it in neutral and pushed it up, down, left and right and it seems to move really easily and seemed like it was where it should be, not half in / half out or anything...
 
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Changing the fluid isn't very expensive - be sure and use the right stuff. I think they have a magnet on the drain plug that will collect steel gear shaving's, yellow glitter in the oil would be from the synchro's.
 
1st and second gear are buttery smooth - if I wind 2nd gear higher than I should (where I should be in 3rd already) it starts to vibrate some, but it only gets REALLY bad in the middle / high end of third and the begining of 4th. Once I pick up a sufficient amount of speed in 4th, it goes away as well - or it used to; now it does the roaring thing.

I can stick my finger in the transmission fill hole and see if there are any gold flecks - or should I just go ahead and drain it and check that way?

As far as being sure about the transfer being fully 2H, I honestly didn't think to check that. I'll go mash on it and see if it is hanging halfway or something...

Edit: As best I can tell it's properly in 2H - I put it in neutral and pushed it up, down, left and right and it seems to move really easily and seemed like it was where it should be, not half in / half out or anything...
I'd just go ahead and drain - refill. Small job, big return.

One thing to be wary is that the transfer linkage can work loose, so the knob moves but the gears don't engage - worth looking underneath while someone else engaged 2H to see that it's all moving correctly if you're at all concerned.
 
I'd just go ahead and drain - refill. Small job, big return.

One thing to be wary is that the transfer linkage can work loose, so the knob moves but the gears don't engage - worth looking underneath while someone else engaged 2H to see that it's all moving correctly if you're at all concerned.
I'll do just that. I'm afraid whatever damage is done is catastrophic though. Already got quotes on a replacement tranny and holy crap I was not prepared to see that cost.
 
I'll do just that. I'm afraid whatever damage is done is catastrophic though. Already got quotes on a replacement tranny and holy crap I was not prepared to see that cost.
If the oil is clean then maybe you can sleep better tonight.

You'd get it fixed and sell it on easily enough anyways to recoup some cash
 

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