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Shifter Vibration - Rattling noise coming from transmission area

15K views 6 replies 4 participants last post by  willis36 
#1 ·
Hello all,

I just replaced my rear main seal, oil pump and oil pan gasket. Now I have an issue that I wanted to throw out here.

Problem: Vibration felt in the shifter; can hear "rattling" noise coming from, what sounds like, the transmission area (the hump on the cabin floor).
It's very noticeable at high RPMS, low gears, e.g. first and second, 2000 + RPMs.

Here is my email with more details to my buddy who also owns a wrangler:

"I'm trying to determine if it's the trans (and/or drive shaft) or engine. I know that I torqued the rear bearing because I put loctite on it and the brace I remember torquing down. Double checked those things before installing the pan. The oil pump, I had a broke a mounting screw but replaced with an automotive bolt. There are only 4 bolts for the exhaust brace and four for the trans plate...the trans plate could the be the culprit, I guess, but why would it start acting up so severely now when it was totally fine before? Man, I don't know. Here's the thing, if I rev the engine with the clutch disengaged I hear nothing. I think, have to confirm, that if I rev the engine in neutral (clutch engaged) I hear and feel nothing. I believe it only happens when in gear and under load (of course, I'd have to jack the truck up to test without a load but that's not an option). If you think of anything let me know.
"
Any insight or 2 cents would be much appreciated.

Other details about my truck:
4" Skyjacker lift (came with it and I know it sucks so no pointing it out)
Lift has spacer bars for the trans plate (again, I know...)
33" tires, no unusual wear
Rear lower control arms replaced and good. Front lower need new bushings but not bad at the moment...same with upper control all the way around.
Rear track bar busing bad

Mind you this was only an issue after the rear main seal replacement.
To replace, I supported the trans on a jack and lowered the exhaust system by disconnecting the front pipe from the mainfold (I also disconnected the front pipe sensor from the engine compartment, not the pipe). This allowed me to pull the pan out from over the front pipe.
 
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#3 ·
I have an update...I'm going to be doing more diagnostics in a few.

I feel the vibration/rumble when in neutral, reving the engine. I did notice my oil pressure is higher, too (I replaced the pump with a Melling pump, it's not a a HV pump, either).
 
#4 ·
The transmission plate is good.
The low pitch, muted rattle occurs with the clutch engaged or otherwise. Which leads me to a theory... But first, a buddy suggested it could be the flywheel. I know for a fact it's not the teeth. I did replaced the flywheel, recently, torqued to spec, with red loctite and it hadn't been suspect to any problems prior to replacing the oil pump and rear main seal. So, I guess while it's plausible, I seriously doubt the flywheel is the culprit. Nonetheless, I'm going to put the vehicle on a lift and check the flywheel.

When I replaced the oil pump, I inadvertently over-torqued one of the mounting bolts. Either my torque wrench is garbage or I'm ignorant...which the latter being something to not rule out. Needless to say I snapped the bolt's head off. Luckily, there was enough "meat" poking out that I was able to spin the remaining thread out and replace with a replacement bolt from AdvanceAuto. Note that I sent my fiancee to get the replacement and we trusted that they would give something in return of equal specifications. I would imagine all an auto parts stores carry are automotive bolts. The other bolt survived but I didn't use the torque wrench. At only 12 ft lbs, and my first failed attempt using the torque wrench at 12 ft lbs, I hand tightened it. This all leads me to my theory:
I suppose it's possible I over-torqued the hand-tightened bolt and, possible, the head pop off when I took out for a test drive...but leads to a couple of questions:
1. is this theory even conceivable?
2. If it is, could that cause it to vibrate, even with one good bolt still attached?
3. If it is conceivable, and it is vibrating, would the vibration likely be more noticeable in lower gears?
4. and if 3 were the case, would it be because of higher torque?

This mess has me stressed out. :thumbdown:
 
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