Damage from driving in 4 low?

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dmr02524

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I hope someone can give me an idea on the extent of the damage. My son who is a new driver had his 2002 Jeep Wrangler in 4L driving one evening. After a short amount of time driving too fast his oil pressure gauge dropped the check engine light came on and he turned it off. When I finally got to it I saw it was in 4L and took it out of gear. It took a little for it to finally start but it did finally start. The Oil gauge shows no pressure, I did check the oil and it has oil. I also noticed some oil drips underneath in places I do believe there should be any oil. However it was not actively dripping. There are no major fluid leques that I can see.

Does anyone have an idea on what kind of damage he could have done?
 
Take a look at the condition of the oil pressure sending unit on the passenger side near the oil filter; verify the sensing wire is connected and the sending unit is not leaking oil.
The lack of oil pressure on the instrument cluster gauge may be a non functioning sensor.
 
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Ditto on the test gauge...most years of the TJ the oil pressure gauge wasn't much more than a dummy light.

If you don't have a test gauge and don't want to buy a cheap one on Amazon...most auto parts stores have loaners.

It's an 1/8" NPT connection located low between the engine and battery. Just above the filter...at least on the 4.0.

Most auto part brand sensors don't work...Mopar and Standard Motor Products are confirmed to be good.

TJ engines are pretty tough.

Kid did good shutting things down when the oil pressure dropped...I just did a head gasket on a 2004 4.0 WJ for a neighbor...their kid ran it got a couple of times before asking for help.

-Mac
 
Well, you don't have the known problem children 05 and 06 oil pump drives, but it wouldn't hurt to check that the cam sensor/oil pump drive is still turning. It's on the passenger side of the engine.

Your 02 should have a rev limiter, so it shouldn't have allowed him to over rev it, unless it's a manual and he downshifted too low.
 
JKP said:
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Your 02 should have a rev limiter, so it shouldn't have allowed him to over rev it, unless it's a manual and he downshifted too low.
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Easier said than done. And if he succeeded, no one would be guessing about the oil gauge and ignoring the blown up clutch or the engine with a big new oily hole in the side.
 
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Thought this was a good video...shows oil coming right out the side of a 4.0 cam bearing.


Not that this is the OP's issue...just topical to oil pressure.

-Mac
 
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I’ve never had either of my Wranglers faster than 15mph in 4lo the revs go through the roof especially my Rubicon. Mine are manuals so the upshifts come up fast. The only one who knows what he did is him. If he is like my kids the truth comes out Much later if at all. The kids drive my Yj and are only allowed to sit in the TJ.
 
bucky said:
I’ve never had either of my Wranglers faster than 15mph in 4lo the revs go through the roof especially my Rubicon. Mine are manuals so the upshifts come up fast. The only one who knows what he did is him. If he is like my kids the truth comes out Much later if at all. The kids drive my Yj and are only allowed to sit in the TJ.
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A plausible guess of 29" tires with a 5 speed manual in low range through a 231 puts 55mph at about 5100rpm. My memory is the rev limiter activates at about 5200rpm.

All things being the same with 35s, he would be cruising at about 65mph when the rev limiter hits.
 
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jjvw said:
A plausible guess of 29" tires with a 5 speed manual in low range through a 231 puts 55mph at about 5100rpm. My memory is the rev limiter activates at about 5200rpm.

All things being the same with 35s, he would be cruising at about 65mph when the rev limiter hits.
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You're not going to hurt a 242 doing that.
 
dmr02524 said:
He says he did not go over 40-45mph. He was driving in town.
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There is no way he was driving even close to 40-45 mph in 4low.

I'm not entirely convinced he was in 4lo (not a knock on you or your knowledge). The engine would be absolutely screaming and he is smart enough to recognize that.

I think the best thing to do is wire up a temporary oil pressure gauge and drive it
 
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