Ad-HocXJ

I could really use some help with this violent vibration I've been having for the past few years. I'm at the end of my wits, and at this point want to send the Jeep off a cliff.
I've spent time searching the forums, trying the solutions that worked for other people with no luck.

The vibes only started when I put the new Brown Dog motor mounts on, as the original ones basically didn't exist. New ones were instantly very violent and hasn't changed since.
I followed instructions to loosen them up and drive with them on, then re-tighten with no luck. Still no difference after several years.

I currently have an oil leak from the rear of my oil pan gasket, because all brands of aftermarket ones I've tried so far (Fel-pro, etc.) have all had the same problem where the rear main seal section doesn't fit. Not even close. This causes oil to cake the underside of my jeep and rear hatch. Only very slight loss in pressure: 40+ @ startup/driving, 20 @ idle. I know that's low cause FSM says min 25 @ idle. Still working on that. Probably going to give up and RTV the $#@ out of it. 2.5L problems.

Engine currently stutters slightly at idle, most likely due to oil leak. Probably trying to maintain oil pressure.
Overheating issues are probably also due to this. Coolant has been changed, heater core flushed (Not entire cooling system). Twice.


What I've done:

• Brown Dog Motor Mounts (Soft Rubber)
• Crown transmission mount (just done tonight, no luck)
• New harmonic balancer
• New piston rings (ultrasonic cleaned pistons and rods)
• New rod bearings
• Glass bead blasted head
• Lapped exhaust/intake valves (were heavily pitted, now in spec)
• New seals for valve springs
• New spark plugs (been a year or more now)
• New oil pan, timing cover, valve cover, head gaskets. Twice.
• New oil pressure sensor
• New Temp sensor (gauge)
• Several oil changes w/ WIX filters
• New drive belt
• New 19lb injectors w/ o-rings
• Cleaned CCV hoses & fittings, added a catch can (Has been dry since re-ring)
• Cut and drilled CCV tubes in valve cover (Recommended by cuiser54)
• New tranny & Tcase fluid
• Exhaust manifold gasket. Twice.
• New distributor assembly
• New shocks, springs with new lift.
• New Walker muffler
• New cowl intake w/ filter. Made sure CCV and gas tank vent were connected.
• New clutch, bell housing, master/slave cylinder w/ stainless line,

I have some things that I think I still need to check, but have no idea if they will help at this point.

• Rear-most exhaust hangar. Completely gone, new one in the mail.
• Rear leaf spring sliders. Ones I got originally were crooked, so springs rubbed against sliders. Kinda straight now, new ones In my room going on soon.
• I put Teflon tape on all the head bolts when I changed the gasket the first time, so second time they kind of gunked up the threads. (I know I should have cleaned them out, but was on time crunch). Maybe this causes head gasket to not seal?
• There is a missing exhaust hangar/clip that is supposed to mount to bottom of bell housing. Maybe it's that important? Exhaust has rest of rubber hangars (except tailpipe), which are all ok.

What I think I need to try:

• Compression test. Post re-ring
• Vacuum compression test.
• ?

Any help on this would be really appreciated, as I have tried every single solution I could dig up over the past few years.

gat

I doubt that the vibration is caused by timing nor compressions, but you may change those.
You can unthread the nut so much so that exposed threads exist on both sides of the bolt for the Brown Dog Motor mounts. The nut is a prevailing torque nut; therefore, it won't budge on its own.
You can always call that company. He is really open about receiving calls for technical assistance.
Also, did you install the new motor mount brackets? I highly recommend changing the stock mounting brackets from the motor for their motor mounts to Brown Dog brackets. You didn't install the lifted motor mounts, right?

BillyBoy

The former response was a great response by a person representing the Brown dog company.... Your engine is not only mounted by the engine mounts but by the transmission mount also... It makes sort of, a 3rd leg How is your transmission mount looking?

BillyBoy

Sometimes, things are more of a system problem then a problem with a specific part.

Dave51

These look pretty OEM:

https://www.quadratec.com/products/5...iABEgL10vD_BwE

Dave51

These guys claim to have OEM:

https://jeepautomotiveparts.com/

Ad-HocXJ

Thanks for all the replies.

I bought some genuine NOS 2.5L MOPAR engine mounts as a plan B in-case the transmission mount didn't fix it. So, I guess the next step would be to maybe try that.

The transmission mount i took out wasn't too bad, had a deep cut along the side of it, so I replaced it. Shifting got smoother, vibration remains.

I only put on new Brown Dog motor mounts (engine to frame of car), as he doesn't make the mounts from the engine to the rubber mount for the 2.5L. And they were non-lifted motor mounts. Stock height.

Lastly, I will fully back out the motor mount nuts to see if they need to be much farther out, but its doubtful. I'll give the company a call during lunch tomorrow to see if they can help.

I appreciate all the suggestions so far, and anyone comes up with anymore please let me know! I'm open to all ideas.

Thank you, will post update tomorrow night.

Ad-HocXJ

I have only managed to install the drivers side mount tonight.




Oh man what a difference! Immediately got much smoother! Rear view mirror now no longer shakes, and is useful again!




Plan on doing the passenger side mount tomorrow, and hopefully the results will get even better!




I called Brown Dog today, and they told me after all I have done, trying OEM mounts would probably be my only option. His reasoning was that some 2.5L engines need the softer OEM mounts more than others. He owns a 2.5l YJ with poly engine and tranny mounts.

He told me to call him to let him know the results, so after the pass mount goes on, I will let him know.




Thank you everyone for the advice!

Ad-HocXJ

Quick update:
Got second motor mount in, Jeep is smooth as butter.

For anyone reading in the future, this may be your problem.

Cheers.

gat

I'm not a representative of the company. I am a product purchaser. The brackets saved my vehicle when the threaded bosses snapped. He had posted that he changed the mount for the transmission. Also, Brown Dog doesn't make mounts for the transmission. I inquired. The owner informed me that he uses a cheaper priced brand and wheels without issue.

I have additional positive experience contacting Fel-Pro about it's gaskets as well as contacting Brown Dog about it's products. I was sent an image and instructions on installation of the oil pan seal. The company doesn't just have the instructions included in the plastic of each gasket because there would be an additional cost to include in each product. I have the 4.0 but I would guess that it is the same issue in your smaller engine. There are some areas that the gasket requires a bead of sealant to be included when you install the gasket. If you contact Federal Mogul, then you will receive technical assistance for the installation like I did.

P.S. I don't work for that company either. I just encourage access to good resources in customer service when available. I always buy Fel-Pro gaskets and have yet to be disappointed. The exception being lube-locker on my Wrangler.

Dave51

Seriously, thanks so much for the update. So many people don't come back after they've fixed their problem like it's a BF secret.

Best of luck!

Ad-HocXJ

Thank you for the insight! I will be making a separate forum post in much more detail and pictures about the oil pan seal for 2.5L soon in the Stock section. Would be great to have your input there!

Ad-HocXJ

Of course! I found that to be an annoying trend too, so I try to do my best to add conclusions to all of my threads. Better late than never!