Smooth in park/neutral, rough in drive

[chicagodiesel]

So, noticing a big difference in the idle of my truck between park/neutral and drive with the brake on. I know there is going to be some difference due to the load being put on the tranny and drive train, but this is a pretty marked smooth to shaking feeling.

Wondering what anyone's thought on this is...flex plate, torque converter? There are not out of the ordinary sounds as described when flex plate bolts come loose. Thanks ahead of time.

And I'm not having unreasonable expectations of how smooth this ride is going to be, I want a good back massage driving around town. However, I would also like to be able to not feel like I just mowed the lawn after getting to work!

 

[chicagodiesel]

I guess I should clarify...

I have replaced the transmission and motor mounts, properly tensioned my belts, installed a new lift pump, changed all filters (fuel/oil regularly, transmission pump filter), replaced fluids (differential, t-case, transmission, oil), installed a new flex plate (starter destroyed the last), there is no debris in the IP check valve (return on top) and glass ball is clean, new return fuel lines.

So, I'm just looking for ideas on where I might try and problem solve with what's left (besides a new IP).

But maybe it's just a dumb question. I'm open to hearing that too. Thanks.

 

[mistaken1]

Nevermind

 

[chicagodiesel]

Nevermind? You're leaving me hanging here.

Thanks Kevin. I will change it around and see what happens.

The windows working out magnificently with in dash switch! They crushed that 87 Blazer before I could get back to it. It was funny, I went there and they told me it was out in the yard...looked for it and then sheepishly walked towards the crusher only to confirm my fears. Oh well. Just wanted the spare and the wiper arm. Also got the windshield washer pump working...mine was missing a spring that yours had. The simplicity of a fix sometimes.

 

[3dAngus]

Not related, but I changed out two fuel pumps, and the fuel filter on my Mercedes, ran fine for a couple of mile, then got rough at higher speeds, even stopped running. Idled fine before all the work, put it in gear, ran rough and barely moved, so I changed out all fuel parts.

Turned out, it was a piece of plastic still in the fuel line.

Idled fine before and after the filter and pump changes. Point is, there is a possibility of something still wrong with your fuel system where it calls for more fuel under load.

 

[mistaken1]

Nevermind? You're leaving me hanging here.

Thanks Kevin. I will change it around and see what happens.

The windows working out magnificently with in dash switch! They crushed that 87 Blazer before I could get back to it. It was funny, I went there and they told me it was out in the yard...looked for it and then sheepishly walked towards the crusher only to confirm my fears. Oh well. Just wanted the spare and the wiper arm. Also got the windshield washer pump working...mine was missing a spring that yours had. The simplicity of a fix sometimes.

I read your first post and was suggesting motor or transmission mounts. By the time I got around to posting my reply your second post was now there where you stated the motor and transmission mounts were new .......

 

[chicagodiesel]

Well, pulled injectors and cleaned them today. Replaced. Started, still rough. Disconnected alternators and power steering to make sure it wasn't a pulley alignment problem. Restarted, no dice, still shaking.

Turns out the engine is shaking pretty good at idle only becomes very noticeable under load in drive. So, seeing my second post you can note everything I have done. I don't think an idle adjustment will cure this one. I'm going to do a spin on filter mod to make sure filter isn't letting air into the line. I don't have leaks but as some have noted doesn't mean there can't be air getting in. Otherwise I'm convinced at this point the flex plate I installed wasn't counterbalanced correctly (from manufacturer) or my torque converter is giving me the wobbles.

I will upload a video tomorrow of the amount of movement. Looks like I have bad mounts, but they were just replaced last week. Thoughts?

 

[Barrman]

How does your exhaust sound? Can you put your ear next to either tail pipe and get a smooth sound or is it skipping and not really a constant beat? I have 3 6.2 trucks here at my house right now. Two of them are smooth as glass at all times and have a very constant sounding exhaust at each pipe. The third truck can't keep a steady beat. That is my 1009. It idles great until put in gear. Then it shakes and bounces a bit. I should be putting a new IP in it next week if it shows up in the mail. I am convinced that is my problem.

Since yours didn't do this before the work, it sounds like you are on the right track. However, unless you put in a new IP yourself, that should always be considered as a problem causer for these 25 year old 6.2's.

 

[uscgmatt]

I was having a shaking problem with mine also. Great in park but it shook pretty good in gear stopped. Then one morning I went to move the m1009 and the only gear I seem to have left is neutral. Guess its time for a trans. rebuild. The pump is hardly pumping any fluid. Hopefully yours will be a little easier. Good luck. Oh and I have a new lift pump, filter, injectors, and IP on my truck.

 

[chicagodiesel]

You know, I just want to believe deep down that there is something that doesn't need replaced on the truck like the IP. I know its a matter of time. No leaking or debris...but I guess that doesn't mean much?

I played around with the timing today, but only achieved getting different amounts of smoke to come from the truck at different moments during acceleration.

Exhaust has continuous feel with same pressures. Although, passenger side is definitely stronger than the driver side. Both mufflers are swiss cheese, so this is where that problem is coming from. Do you think different back pressures on the exhaust could cause the engine to shake? Hmm...maybe I'll chop the mufflers off and see what happens! My neighbors would love that. They already think there is a UPS truck outside every morning.

Mufflers need replaced anyways. Maybe I'll drop some more cash this week and take care of that! Any suggestions on decent mufflers for a good price or will anything do (like the 18.99 universal mufflers)?