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Unread 06-02-2007, 07:17 PM   #1
jesse187
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how to replace bearings in 4.0

Ok my 4.0 is needing some fresh bearings and i was wondering if i had to pull the motor to replace the rod bearing and the main.

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Unread 06-02-2007, 10:08 PM   #2
4.7stroker
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Na just pressure wash the underside of the motor and surrounding area.
Drain the oil.
Disconnect the neg battery terminal.
Remove the oil pan clean and set aside.
Remove 1 main cap and remove 1 rod cap.
Note the condition of the bearing material and the condition of the crankshaft.
Remove bearing shell from the main and rod caps that you just removed.
The size will be on the back of each shell.
Order a set of bearings using these sizes, just take them to a machine shop they will get you the correct bearings/gaskets and oil pump. get assy lube also
2 days later
Take the new oil pump apart clean everything and fill it with assy lube then put it back together, set it aside.
Loosen all main bearing caps 2 turns.
Removing one at a time push the shells out of the cap then using a brass drift push the shell out of the block.
Lubricate the bearing face with the assy lube install the new shell in the block.
Install a shell in the clean cap apply some assy lube and loosly install the cap back on the crank.
Repeat 5 more times.
When all mains are replaced then torque all mains to spec.
Then move on to the rod bearings do them in the same manner.
WARNING any sand grit dirt etc will destroy your new bearings wasting your time money and effort.
You may still have low oil pressure because you have not replaced the cam bearings but unlikely.
Install pan, change oil filter if not done, refill with oil, reconect battery, start engine and hope for the best.
If all works out well drink beer and tell everyone how good you are.

Dwayne
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Unread 06-03-2007, 11:00 AM   #3
4.7stroker
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Oh yes don't forget to replace the rear main seal while yo are in there.

Dwayne
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Unread 06-06-2007, 07:13 PM   #4
jesse187
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thanks for the info
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Unread 04-15-2009, 12:42 AM   #5
02wrangler_guy
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i have this freaking knock problem from under engine and is noticeable and very loud at idle once warmed up and will be dropping the pan next week for inspection, thanks for the good instructions ill let you know how it goes.
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Unread 04-15-2009, 10:40 PM   #6
StewCJ
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Yea sounds like a spun bearing or loose rod bolt. Careful driving it with the knock, I'd let it sit.
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Unread 04-16-2009, 10:09 PM   #7
robsjeepxj
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If it's only at idle you should save your money for a minute and check your flywheel bolts first. Mine did the same thing I freaked out until I talked to local jeep tech guy and he set me straight.
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Unread 04-22-2009, 01:40 PM   #8
02wrangler_guy
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well i havent had the chance to drop the pan yet been working all the festivals in austin every week (tiss the season for great weather, festivals and alot of beer) but i did check my torque converter bolts and they seemed to be a little loose re-torqued them with torque wrench and noise is still there. so maybe i will drop the tranny and check the flywheel bolts, hell i could even start the engine with the tranny out and see if the noise still there from the engine i guess. I am i right to think the engine will run with the tranny out??
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Unread 04-27-2009, 11:57 AM   #9
02wrangler_guy
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ok well i dropped the pan and inspected the pistons and rods every thing looked good the enigine is really clean!! i pulled out all the rod bearings and inspected and went a head and replaced them all since i had it apart and the parts were inexpensive. the old rod bearings didn't look bad either so at least i have the piece of mind that no pistons broke and all the rod bearings were ok. next will have to be to pull trans and check flywheel bolts and bellhousing bolts i guess. i have heard that this noise is just normal but i still dont like it and it worries me. anyone else have anythoughts as to what to do next, or anything i missed?
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Unread 04-27-2009, 05:55 PM   #10
iluvtruenos
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Wait, so you just popped in new bearings?

You might have just F'ed up royally.

Gotta go to class, so I'll leave you with a cliffhanger.
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Unread 06-22-2009, 11:39 PM   #11
boda
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just heard same noise,freind had same problem,fixed by replacing rod bearings. i also see fluid coming out from back of transfer case,where drive shaft enters yoke.??? i will replace seal and see if continues. i am in need of suspension lift, like to go 4", still looking what manu to use,,any suggestions?
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Unread 07-31-2010, 11:02 AM   #12
Dissenter
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Quote:
Originally Posted by 02wrangler_guy View Post
i have this freaking knock problem from under engine and is noticeable and very loud at idle once warmed up and will be dropping the pan next week for inspection, thanks for the good instructions ill let you know how it goes.
I have this same problem, did you ever get it fixed? Did the rod bearings take care of it?
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Unread 10-12-2010, 12:28 PM   #13
jclaudii
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update?
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Unread 10-29-2010, 04:28 PM   #14
iluvtruenos
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My girlfriend's XJ has the same exact problem. Loud knock coming from bottom end, sounds like a midget with a sledgehammer playing drums with her connecting rods. Flywheel bolts are tight, but what I've noticed is that if the #3 cylinder pushrods (both intake and exhaust) are removed, the knock goes away. Knock is still persistent with no spark or fuel, but working pushrods. Could a lifter be bad?
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Unread 05-04-2011, 08:54 AM   #15
Jason_alex
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Great thread
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