jeep93

Hi guys - in my opinion (for what its worth) my xj is running just fine.. however, a neighbour who is a trainee mechanic says it sounds like my camshaft is badly worn and causing a loud whine type noise. Ive temporarily posted a short vid on utube.. your welcome to listen for yourselves, and your opinions would be greatly appreciated!.

Jamie57

Hate to tell you this but it sounds more like the front pump on the transmission to me. Have you checked the fluid level? You may get lucky and it's just down a quart.

2Evil4U

I had a power steering pump that was very low on fluid sound a bit like that once. It doesn't sound cammy to me. I've had chain driven cams wear to the point of being able to remove the chain without removing the sprockets and they never sounded like that.

jeep93

Thanks for the quick responses guys - the trans fluid and the power steering fluid levels are fine... of course that doesnt mean the pumps are fine.. gives me 2 areas to look into further!. Appreciate your time guys.

Jamie57

Hmm forgot about that. Another likely culprit.

jeep93

I climbed under the jeep while a friend revved the engine.. the noise is definately coming from the transmission area. While under there I noticed a small amount of fluid that seems to be leaking from the front of the transmissions main body. I checked the fluid level (which was fine 2 days ago), and its definately dropped a little. Topped it back up, but the noise is still just as loud.
Im getting scary prices online regarding the cost of replacing a front trans pump.. in some cases up to £1000. Apparently it requires dropping the transfer case, and breaking down most of the gearbox.. might be cheaper just to stick an AX 15 manual in it..

fantic238

Stick with the AW4. There are several things i would check before swapping the tranny. (easy find in every JY, not that expensive).
First of all, remove the serpentine belt and start the engine to be sure that it isn't coming from the PS pump or the AC compressor, alternator etc.
Oil pump (engine):
How's oil pressure? If the crankshaft bearings have excessive paly it will damage the new tranny aswell.
Torque converter:
does it diminuish when you drive in third/fourth and the lock-up engages?

Bustedback

A trainee's diagnostic skills are not to be trusted, you'll spend more money on useless repairs because of a trainee that knows just enough to get in trouble.

jeep93

Thanks for the good advice guys - didnt think to use the serpentine belt (or lack of) in a diagnostic way like that - I learn something new on this forum everyday!. I'll do that tommorrow to rule out the ps pump, ac compressor, etc.
The oil pressure seems good. Interesting question about whether or not the noise eases off in the higher gears.. took it for a drive and it does quieten down a little in 4th gear and a lot when the overdrive kicks in.. does that indicate a torque convertor issue?..
Agreed on the trainee thing.. he didnt mention any of the possibilities you guys have come up with.

fantic238

Et ualà.. now you gotta find out whats wrong with either the flex plate or the crankshaft. Remove the dust plate from the bell housing and check the flex plate bolts.

jeep93

something going on with my torque covertor. When I first got the jeep it was making a knocking noise when starting and when the engine was revved. Tracked it down (with the help of this forum)to the torque convertor flex plate. It was missing a few bolts, and the remaining bolts were barely hanging in place. I replaced all missing bolts with the proper guage of "place" bolt, and tightened them all up to the right torque with a little loctite.
When I opened the inspection cover today, 2 bolts fell out, and 1 is "missing"... must be embedded in the bell housing somewhere out of sight. Only 2 remained in the flex plate, and they do seem to be nice and tight. Now I just need to figure out why my torque convertor is spitting out bolts?.. and is it related to that whining noise??. Your never short of something to do when your the proud owner of a jeep!.

fantic238

I knew i was near..
The torque converter has lost the centering due to the enlarged holes.
Unfortunately you need to replace the flex plate, hoping that the torque converter hasn't damaged the oil pump.
Disassemble.

CheepJeap

Sounds like you corrected it correctly. I would repeat it again and double check the lock tight tht your using. They make different types depending on the application. The one I use more often is, I believe 602 which is RETAINING COMPOUND. Basically it won't come loose with moving parts.

jeep93

Yea - reckon youve pointed me in the right direction with the torque convertor fantic - appreciate your help there. And thanks for the tip on loctite 602 cheepjeep.. think I'll go ahead and retighten all the bolts with a little 602, and see if that helps... if not, then I guess its time to start dissasembling..

jeep93

Bolts came loose again, and the whine got a lot louder.. then a knocking nosie appeared. Jeep was driving ok, but when I came to a stop it would shudder as if the engine was about to stall. It felt a bit like coming to a stop in a manual car and forgetting to dip the clutch (which I do in my wifes car a lot!). The shuddering stopped when I shifted the box to neutral. I remember reading that the torque convertor is what allows a vehicle with an auto transmission to come to a stop while remaining in gear.. another possible indication that my torque convertor was not very well. I admitted defeat and took the jeep to a local mechanic recommended by several of my work colleauges.. they said he was competent, honest and always gave a fair price, so I thought Id get him to look it over. Turns out my flex plate was suprisingly badly cracked.. it seemed ok when it was in place, but when he took it out it was a mess. It practically disintegrated(I was there when he removed it). £74.52 for a brand new shiny flex plate, and £30 labour... total cost £104.52. Good news is the whine, knocking and shuddering are gone!. Bad news is I feel like a wimp for having to take it to a mechanic.. well, you live and learn.. next time I'll know what to do.