Hi, I have a '97 F150 Standard Cab 4x4 5.4, lately Ive been getting this real harsh vibration, kinda seems like hopping. Its seems as if its coming from the front driver's side but I was told its probably the rearend. I just repaced the ball joints/ control arms upper and lower, didnt help. The vibration happens when I take left hand turns and when I go fast from a standstill in a straight line. If there are any who've experienced this, any info is greatly appreciated. Thanks!

 

Make sure you are COMPLETELY out of 4x4. Could be it somehow got engaged but never disengaged completely. That sounds like the 4x4 is engaged and it is the normal wheel hop you get when turning in 4wheel drive on dry pavement.

 

Ill see if the hubs are totally unlocked. I started noticing this vibration the day after I took it to Les Schwab to get the front left stub axel replaced. Could it be that they didnt install it correctly? Also, recently I had a new shock put on the left rear after driving around for a month with a new one on the right and the stock one on the left. Could that cause any vibration? The tech that told me it could be the rearend said that the ring and pinion could be binding or breaking teeth.

 

this real harsh vibration, kinda seems like hopping.



that is the textbook case for bad clutch packs! did you replace the diff fluid with the wrong type?

 

ford390gashog is correct. Seems to me also classic case of differential clutches.

 

I never changed the diff fluid. I dont think the fluid was changed when Les Schwab replaced the front drive axel. Whatever the vibration is, its coming from the left side of the truck. Whether its from the front or rear I dont know. Im figuring that it has something to do with the replacement of the axel, the truck has never acted up like this before. Could the installers have locked the hub while putting the axel in? My truck has automatic hubs. Im new to the forum, so thanks for the feedback guys.

 

There is also the possibility then when they re-assembled it, they thought it would be good to grease up the hub. Yes you do need to have it lubricated, but not with grease. The springs in the hubs are not that strong and a blob of grease is enough to keep them from moving. One of the better known steps is to clean the hubs grease free with brake cleaner then to soak them in tranny fluid and put them back in. I did that with my manual hubs after hearing about it and they were smooth as silk from then on and worked great.

 

I would change diff fluid and ad some posi lube ...sounds like fords tipical rear diff clutches scrubing....they need new fluid and additive.....Put the right stuff in too.

 

its not coming from the front but the rear. the clutch pack is toast.

 

I hope its not the rearend. That could get spendy, ill check the fluid, but the clutchpak? If it is the clutchpak would that mean that its done for, or can I save it by flushing the fluid and putting in an additive? Thanks for the info!

 

that feeling is 99% the rear end. if the clutches are wron out nothing will save them.

 

Ill have Ford check out the rearend. Its weird that the truck started acting up the day after I got the front axel put in though. Also, I drove around for about a month with two different shocks in the back, could that mess it up in any way?

 

I had Ford take off the rear diff cover and check it out. The said there was no sign of metal flakes or anything visibly wrong with the gears or spider gears. Oh, they did say that there wasn't any LS additive. Im gonna drive the truck for a few days to work the additive into the clutchpaks. Im pretty sure that its the front drive axel that got replaced, Im gonna check that out next.

 

That additive does wonders......you'll know in a few days.......do some tight parking lot turns nice and slow...each direction ...that might speed up the process.Solved my problems.

 

Should be easy to tell if the 4wd is staying engaged.. take it off road and see if the problem goes away when you're not on pavement. If it stays, then its probably not the 4wd.