Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: Motul on February 15, 2005, 09:33:05 PM

Title: Chassis oiler!!
Post by: Motul on February 15, 2005, 09:33:05 PM
I`ve just realised why I occasionally have a very thick oil dripping from a couple of the holes in the near side chassis beam!!!.......

The rear diff breather pipe is fed into it - so it looks like my rear diff houseing is somehow being pressurised, and dumping its oil!!!!  #-o
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Post by: Bubba on February 15, 2005, 09:53:21 PM
yup overfull only slightly but thats cus its comin out the breather and not leekin from anywhere else :roll:
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Post by: paul on February 15, 2005, 10:07:16 PM
Hey! Motul, my Cherokee did exactly the same thing after i had 3" lift fitted, so back it went to the people that fitted the lift, lot of head scratchin went on, they were very concerned as had never heard off this before! even rang Procomp. checked level in diff ,oil was level with lip of hole, so had breather pipe disconected and put into plas bottle zip tied to body, checked bottle over a week no more oil came out only conclusion as to why oil came out of breather is that when you fit lift kit angle of diff changes slightly which makes the diff over filled so excess oil is pushed out of breather pipe hope this helps you Paul
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Post by: Motul on February 16, 2005, 08:42:35 AM
Cheers guys, I was hopeing that was gonna be your veiws!! :-& , (sorry, wrong thread)

Thanx again  :wink:
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Post by: daggie on February 16, 2005, 03:58:31 PM
It'll only be a few degrees, you should be ok.
If you're gonna do a lot of deep water stuff you need to extend the rear breather anyway
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Post by: Anonymous on February 16, 2005, 04:19:05 PM
Wate :roll:  uggh
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Post by: Woody on February 16, 2005, 08:18:05 PM
Mark at MDG fitted a diff cover to my rear end which has a much higher fill hole, this means that even with the angle of the diff with a 3.5" lift the diff still has loads of lube :D  Just saving my pennies for the armoured front diff cover he sells.

Woody
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Post by: Bubba on February 16, 2005, 10:33:00 PM
sorry woody i rekon thats just a load of hooey you dont lose enough oil capasity to  make a real diferance they are just super sexy [super pricey] bull shit that some folks like to sell just cuz they can :flagbs:  :smt028
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Post by: Woody on February 17, 2005, 12:30:13 AM
Well I like it and it was not too expensive, especially as the old one was severely pitted.....insert raspberry sound here..... :D  :D

Woody
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Post by: Anonymous on February 17, 2005, 12:48:40 AM
Scrap scrap :shock:
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Post by: Motul on February 17, 2005, 09:22:34 AM
I think I`m gonna copy Paul, and rig up a catch bottle and monitor the loss!!  :?
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Post by: Woody on February 18, 2005, 06:49:46 PM
Got a better technical explanation for the raised filler hole on the rear diff cover.  This is a TJ with 3"+ lift with short shaft conversion issue and is not such a problem with the Leaf Sprung CJs & YJs.  

In the TJ with a short shaft conversion the axle rotates further than CJ & YJ putting the front bearing higher above the oil level.  At high speeds splash lubrication is sufficient but a slow speeds, ie offroad, insufficent oil would reach the bearing.  By raising the oil level you regain the oil bath effect lubricating the bearing.

Woody
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Post by: ivanidea on February 18, 2005, 07:30:27 PM
Does this mean that when I refill my diffs (4.5" lift fitted, ARB lockers), there is insufficient oil in the diffs/axles with the standard covers?

Ivan
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Post by: Bubba on February 18, 2005, 07:43:27 PM
well woody i rekon you must be plannin to to do all your froadin on a bowling green as if you reason held water or rather oil the constant ups down  and piching from side to side would lubricate every thing a treat and dont forget regearing does actualy increase the rotation speed of the crown wheel and pinion hense the lower overal gearing so this to trows the oil more not tellin ya what not to spend on i just think that there are some trendy things about that dont realy justify themselvs
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Post by: Woody on February 18, 2005, 08:10:03 PM
We'll have to agree to differ here. I like the piece of mind the higher level gives me, having spent a lot of ££ having the axle rebuilt not spending a comparatively small amount of money to ensure good lubrication seemed daft to me.

Woody
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Post by: Woody on February 18, 2005, 09:55:18 PM
Bubba

just reread your last post :?  Surely if you regear to 4.56 then you can look at it from the point of view of:

a.  Road Speed, say 40MPH - The crown wheel still turns at the same speed - the speed of the axle, the difference the regearing makes is that the pinion must rotate faster for the same road speed.  Which is why until my transfer case speed pick up was changed I went from an accurate speedo to one that was overreading about 1.5 times.

b. Engine speed, say 2000rpm - The pinion wheel still spins at the same speed, now however the crown wheel will be spinning slower.

either way you look at it crown wheel speed has reduced compared to pinion speed so less splash lubrication than with original gearing.

Woody
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Post by: Bubba on February 18, 2005, 10:02:45 PM
i think realy it is one of them so so things the thery behind them is sound but how much they truely offer is down to how you interprit things you are happy so i think that is the mane thing
sorry if my las post was unclear apoligys for that