No front shaft...

I have heard that the front shaft operates the oil pump in the t/fer box. If you run without the pump ,lubrication is poor. The standard procedure is to engage 4wd.

sorry but must say I have stripped and repaired my transfer case and it does have a small integral oil pump that only works with the rotation of front drive shaft . Engaging 4wd powers the front shaft flange working the pump which otherwise would be stationary when driveshaft not attached cheers hope this helps :wink:

For about a year ago, the same question came up on the Pointed three forum.
The answer was, at least for me, very interesting.

Quote:

Author Posted 6/22/2007 7:18 PM

hipine

Offline

Date registered: Jul 2006
Location: Bailey, Colorado, USA
Vehicle(s): 1980 280GE --> 300GDT

Re: Front Drivesharft removal
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dai - 6/22/2007 9:37 AM It may not be directly related to the pump, I think that when the front is run without a driveshaft and without SA selected, the oil is starved to some components because of the way oil is flung off gears and routed to critical areas. There are channels inside the T-case that flow oil where it needs to go. Whether it comes from the pump or tossed off of gears and rerouted, the bottom line is that more than one gearbox has been damaged by not running in 4WD with a front shaft removed. I have a lot of miles with my front shaft removed, driving in SA without a problem. Happy box. Nothing negative doing this. -Dai

There are actually two "pumps" helping ot oil the bearings on the front input shaft of the transfer case. Oil is flung from teh gears and gathered in a little tray in the top of the box. From that tray oil flows into a passage above the tail end of the front output shaft in the area that's covered by the speedo drive. The rear cover of the transfer case in that area is machined in a way that the spinning front output shaft creates hydraulic pressure that's relieved through a hole leading to the rear output shaft. This machining of the rear cover is the first "pump" in the oil supply chain. This is the one that does not work properly unless the front output shaft is driven.

The pump that one finds in the EPC and in the workshop manuals is the "second" pump. This one is fed by the first one. The second or main oil pump is in fact on the rear output shaft and is driven by that shaft spinning, so it's actually driven all the time, no matter which drving mode the shifter is in, or which output shafts are attached.

I think this is where some confusion comes from. People who look into it a little deepr think, "Well there's the oil pump, it's on the rear output shaft, not the front, so I can disconnect the front without worry." But in fact, that pump can't function without the first one feeding it, and the first one is just some machined grooves and holes, so it doesn't show up on any parts list.

The second pump takes that oil fed to it from the first pump and moves the oil up a hole in the center of the front input shaft. The bearing near the front end of the input shaft is the low range input gear bearing. That's the one that suffers when iol feed begins to falter. Since you don't drive in low range a lot, that bearing can be damaged by oil starvation when the front shaft is removed, but not show up until you later run in GA a while and try to load that damaged bearing. Or if the damage is bad enough it can break up just from un-loaded running since the gear and shaft are running at differnet speeds any time the box is in S or SA mode.

There are lots of other threads to be searched here and on BWF with pictures, etc if anyone's interested in more info.

-Dave G.

End Quote.
Wkr.
Wout

I ran my 230 without front prop attached without 4wd engaged for months, the only thing that doesnt work is the speedo.