snap a pic of that dangling plug and post it. there's something fishy about "a bad muffler that causes NO back pressure." hmm...

 

It's called a clogged cat, LOL

 

heres the wire i found unplugged. I called a few shops and told them my problem shaking at 45-55 and it stops when i hit the overdrive off button and they siad it might be a transmission problem.

and about the clogged cat I just figured when I replace the muffler I'll drill out the cat as well, will it throw a check engine light since I only have a pre-cat 02 sensor?

 

Photo was too big before here it is

 

Hmm, I don't recognize that particular plug, and you have both trans sensors plugged in by the pic, not much reach for that plug, and it looks factory.

If disengaging the OD unit removes the shutter, then I would say yes, you have a trans problem. more than likely the OD unit is not engaging because the snap ring has broken into several bits and are laying in the bottom of your trans pan. if you pull the pan and find small curved bits about a half inch thick, that's more than likely your problem.

 

Is there any thing else that does not work?

 

it has a little trouble shifting at 40 as well, if the transmission is the culprit would it even be worth taking in to get fixed? has anyone had or heard of this 45-60 shaking problem with the transmission is it a big expensive problem?

 

spark plugs for sure just happened to me

 

Lol, well might as be easy as replacing you tires? are they in bad shape? My truck did the same thing with bad tires, and now its perfect, it can go 120 and not shake. its a beast. But yea do you have bad tires?

 

Does it only shake while under power from the engine? Sounds like this is the case, which would lead me to investigate a power train issue rather than a chassis one.

I propose a simple test to check if whether it's definitely an engine miss or not.

Your goal is to get the engine in OverDrive WITH the Torque Converter locked at the lowest speed possible. When your trans shifts through the gears all the way and goes into TC lockup, just barely ease off the gas until you find it's lower limit before it downshifts.

Once you've done this a few times: while at this speed, slowly apply the gas just a bit to stress the engine WITHOUT downshifting the transmission. You're trying to load the engine.

Now,

Feel the vibrations....

....

Are they good?


Long live the Beach Boys, now back on topic:

With a touchy foot, I'm able to get my truck down to ~36 mph in OD with the TC locked. At this point, an engine miss was VERY obvious. The locked torque converter carried the miss perfectly. At no other point while driving could I pinpoint a miss. It even idled okay. 'Twas a burned valve in my case.

When you turn off overdrive, the engine will be in higher revs, which can conceal an engine miss. With the engine lugging, the miss will be pronounced.

I'm not convinced that it's a transmission problem just yet....

-JT