Subliminal ...

What you're describing almost sounds exactly like what my donor truck was doing when I got it.

Good at idle, rough mid-range and would shake the truck apart when you tried to get her all the way up ...

I believe what fixed my truck ensuring the KSB solenoid had a good connection. (I fixed a few things at once)

I changed my spade terminals to ring terminals, cleaned all the connections and she now purrs like a kitten.

 

I actually recently cut the ends off the two wires going to the fuel pump, and I think it was one of the two...cleaned it all up and put new spade connectors on...

I wish that was my problem...maybe I'll double check!

Thanks for all the replies, fellas...anyone else...feel free to chime in, too!

I wanna track this puppy down!

 

I recently had the front motor mounts replaced - passenger side was broke and drivers side was cracked badly...

Now I've got a vibration that starts about 1100 rpm and gets worse to about 1800 rpm then gets less as r's go up more.
What's really bad is the bench seat springs must be harmonic or something because the whole seat vibrates in time with the engine.

Cool massage but I can see this being a MAJOR PITA on a long trip...

I'm replacing the trans rear mounts next week, hope that'll quieten things down...

 

Yeah, I have new mounts under the tranny as well.

Good luck, though!

 

So, I noticed something weird last night that I thought was worth mentioning:

In gear, when I let the truck go to the governor (remember 3200 spring), it will run semi-smooth (normal) up till it hits the governor, and then it feels like it backs off just a little and when it does this, it vibrates so bad it feels like the truck is going to fall apart.

 

I don't know if this applies to the getrag or not but the nv4500 can suffer from a warped bellhousing, causing a vibe. There is a spec for this, something like .010 off max. It changes how your input shaft mates to the engine and will at the very least make for short lived pilot bushings. I have also received freshly machined flywheels that were 'balanced' but still vibrated. Removal and another balance check showed to be balanced, but a new flywheel is what fixed the problem.

James

 

Have you removed the balancer or the serpentine belt yet?

 

Yeah, I did that last night. Didn't make much change.

My guesses at this point are:

Fuel system
Something behind the engine.

I don't really know what to do at this point to check out the fuel system. I've had injectors tested and replaced with no change. I've changed the fuel filter.

Behind the engine, I just need to have some time I guess. I can borrow my friend's ATV jack again and pull the transmission. If I do, I'll pull the tranny out and leave the clutch and such and then start it, see if it vibrates. Then pull the pressure plate and see if it still vibrates. I've another pressure plate I can throw in, if that's the issue.

Grrr. Getting too cold to be out there crawling around under the truck, but I can't take much more of it...it's really starting to **** me off.

 

Any possibility that the drive train is mis aligned.(since this started after the swap) I had a vibration after I did the downgrade, no where near what you are describing but still there.
Also do you have any other manual trucks to compare yours to.

 

I haven't seen a first gen other than mine in...well, I can't even remember.

Drivetrain could be misaligned...I'll tell you what...if I take this all back apart again, you can be damned sure I'm going to try and be precise when I reinstall it all.

 

I'm keeping this one up at the top for more suggestions.

I noticed the last few days that it vibrates WAY more in the AM, now that it's getting cold. Drive home from work isn't so bad, but drive in makes me sad to own it.

 

I would try putting your old sticks back in to see if it makes a difference.

 

Well, it didn't make a difference when I switched to the new injectors, as far as the vibration issue goes, so I'm not sure if that'll help...but I appreciate the suggestion!

 

Oh, sorry. Missed that time line...

 

That's ok...like I said, I appreciate the help...I'm hoping someone will make a magic suggestion I haven't tried and I'll be able to get past this issue and move on to just enjoying the truck!