95 F150, stick shift, all stock.

#1: When I let off the gas while it's in gear, about 30ish and down I get a shudder. If I push in the clutch it goes away.

#2: About 65+, another shudder I feel through the steering wheel. It sets on quite quickly and stays on up to 75 ish which is about as fast as I have driven the truck. Does not do it at the same RPM in any other gear. Up till then it accelerates smoothly and seems fine maintaining speed.

We just replaced a motor mount which I totally hoped would fix it, but it did not. The mount was totally thrashed so it wasn't a waste of time, but it didn't fix my problem either.

I am kind of at a loss of where to look next. The transmission mount is solid, and I do plan to but haven't had time yet to take it in and have the wheels balanced. That might be the speed vibration but I doubt it is the decel problem?

So where else should I look? If it was like my old Jeep I'd immediately think pinion angles, but this is totally stock so I don't know how that could be it. Maybe the driveline needs to be rebalanced or something? How do you tell? The u-joints look OK, maybe that is something we should just replace anyway, they aren't expensive. What about front end parts? could it be a bushing or steering link or something? Something to do with the TTB front end? The big bushings on the arms look OK, I know that was an issue with these front ends.

I hate not knowing what's wrong I sit here and imagine the worst. I drive it every day to work, so if there's something serious we need to get it taken care of soon. We are getting low on functional vehicles for my husband and I. Maybe this is an excuse to fix a few things and start driving the Mustang to work? (that sounds fun in traffic)

 

Sounding little bit like weak pressure plate.

When happens slowing down heavy or light deceleration?

Cruise condition in top gear, will it go away under heavy acceleration? IE; can cause clutch to slip?

 

it does it under most deceleration conditions, it starts about 30 and gets worse the more compression the truck is under--like putting it in first gear and putting up to a stop sign, I really feel it then.

Acceleration does not seem to matter at higher speeds, it starts at about 65 no matter what you are doing, accelerating or just maintaining speed on the highway. Up to 65 it feels fine under acceleration no matter how heavy my foot feels that day.

It doesn't *feel* like a clutch slipping, we just replaced the clutch in our Subaru and it was really bad so I remember what that was like. But maybe it's a different feel than a little car.

It has about 170k on it, shouldn't a clutch have a little longer life than that? The Subaru died at 240K and my old Toyota was about 230k or something when it got real bad.

It was used by a contractor though so maybe it saw some heavy abuse. He also had a 3/4 ton Chevy so I don't think he used this truck for a lot of towing or anything.

 

Subaru be a lot lighter then a 3/4 ton truck even though the truck would have a larger clutch to start with.

Not sure yet it is pressure plate shutter, kinda sounds like it might be based on your comments so far.

Weak pressure plate, it will more often then not cause a "shutter" at take off, first or second gear, does so while starting off from a stand still. Get any of that at all?

 

No, it feels fine when taking off.

It IS a little weird to put in 1st gear from a dead stop, but it's always been that way.
Another symptom of some sort of clutch issue?