Hi all,

Brand spanking new member here. Also a proud owner of a 1995 4x4 f150 XLT, auto (3speed with OD) with 184,000 miles. I've been driving a '91 2x4 f150 lariat as a work truck and have been loving it, so I bought this one to take my family camping with a trailer.
As I was driving it on the freeway, I started noticing some vibrations (hubs are in the "free" position) I was going about 70mph. They went away on inclines, and when I took my foot off the gas pedal. When I did that, though, I noticed a "clunk" sound. Is there something wrong with my transmission? I also feel a clunk when I shift from R to 1st.
Thank you very much.

 

Welcome to the forums BkeyMikey!

Congrats on the f150, hopefully she will give you years of service!

Start by checking your speed sensor, it could be going bad and confusing your tranny. That being said, it could be a number of things. This is just merely a suggestion

 

welcome to the site and on your purchase of a great truck, i would hafta agree about checkin the speed sensor

 

would a bad speed sensor be the cause of the clucking sound, whiplashy feeling I get when I shift from R to 1st, or the slight clunk I hear/feel when I let off the gas?

 

Check the driveshaft universal joints for any play.

 

Drive shaft is my bet

 

U joint is my bet

 

check the following man, in no piticular order but still check the following...

drive shaft - check for any play (loose)
u-joints - same as drive shaft
check speed censer (psom/vss)
tranny (just for the heck of it, your truck shouldn't go thunk here)

 

Ok, first off, don't bother "checking" your speed sensor. It has nothing to do with the problem.

The clunk is probably your u-joints. Jack up the rear axle and support it with jackstands. Crawl under it and check all the u-joints in the driveline for free play. They should all be tight. If there is movement in any of them, replace them.

 

Trans yokes will bind then 'clunk' when the pressure is released. Had this happen when all the usual checks in the driveline were checked and dbl checked. Under load, the yoke (splined) is under pressure and held in place. when the pressure is removed, it slides to the 'new' position.
Hope this makes sense.

 

thanks, everybody. i crawled under the truck, and sure enough, with it in N, the rear drive shaft u-joints had tons of play in them. i got some new ones, made by precision.
i've been on youtube, and it seems like there are millions of methods to remove and replace these puppies, using hammers, bench vises, u-joint presses, extractors and installers. i'm thinking i'm going to try to rent a u-joint press and not use the hammer or bench vise methods. i hope this tool will allow me to install the u joints straight, without loosing any needles. do you have any suggestions?

thanks!

 

That u joint press is the tool to use spray em with pb blaster to losen them a bit

 

the tool makes it easy but be real careful so you dont knock the rollerbearings out of place when you press them in just be patient

 

I always supplement the factory grease with some hi-temp grease, for to hold the needles in place, and to guarentee coverage if a grease gun in't on hand yet, or the u-joint isn't a zirk style. Dab a little on your finger and add to each bearing cup. Never had a needle go sideways on me.

 

Welcome to FTE!