Further explanation of why putting longs output in completely eliminates the oil pump....
COToy91,
Thank you for asking for more info on this. It has brought more dangerous information to the surface which I believe must be fully understood if you own a Bobby Long output shaft and intend to drive your truck in any gear in any range and at any reasonable speed.
Please consider the following illustration:
I can get a solid works drawing of this when I get home that will be easier to understand.
The Red circled part is the oil pump. This is located in the tail cavity of housing #4. Oil is designed to be caught and transferred into this cavity where it is caught in the grooves of the oil pump and force-feed through two holes and into the center of the output shaft. As more oil is pumped into the output shaft, the oil is displaced down the center hole of the shaft and exists at the following three locations:
1) The Front Output Gear Cage Bearing (circled in green)
2) The Low Speed Gear Cage Bearing (circled in blue)
3) And out the front of the shaft to feed the input pocket bearing (bearing all the way to the lower left of the image)
--If you are in 2WD High Range, then there is no load on the front output gear cage bearing, no load on the low speed gear cage bearing, and the input pocket bearing is locked in a 1:1 ratio with the output shaft, so although there exists a load on the pocket bearing, it is not rotating relative to the output shaft and therefore no heat is being generated.
HOWEVER, because the front drive shaft is not spinning, the front output gears are not spinning, and that means that the front output gear is not moving BUT the output shaft is moving!! So the gear has a rotational speed of zero and the shaft is hauling the mail. Therefore the bearing circled in green is working and generating heat and if you are on the road or *gulp* highway, that bearing is spinning very fast with out any oil.
This bearing (circled in green) is surrounded by a slip fit shift hub and a thrust washer, making it extremely difficult for oil to enter the cage bearing from either side. This is why at that location on the output shaft there are two side ports that are drilled through the output shaft connecting the inner diameter oil supply with the cage bearing. It is critical to that bearing to get oiled and with the Bobby Long Output shaft it is not.
ADDITIONALLY, the low speed gear cage bearing (circled in blue) is also moving because in 2WD high range the shift hub connect the input to the output shaft (1:1) and since the input gear is always turning no matter the range, that means the counter shaft is always turning and therefore the low speed gear is always turning and therefore the output shaft is ALWAYS rotating at a speed of 2.28:1 (or 4.70:1) times faster than largest low range gear there, the low speed gear. So that cage bearing is generating heat all the time.
So driving around in 2WD High Range is the most dangerous thing to do when your transfer case has a Bobby Long Output shaft because you are most likely to travel at higher speeds in 2WD High Range which will starve the front output gear cage bearing from oil as well as starve the low speed gear cage bearing from oil.--If you are in 4WD High Range, then at least the front output gear is locked by the 4WD shift hub in a 1:1 ratio with the output shaft, but the issue with the low speed gear cage bearing (circled blue) still exists. Of course the added load of the front wheel drive components will put a larger load on the transfer case which would generate even more heat than normal.
--If you are in 4WD Low Range, now the input gear is rotating at a ratio of 2.28:1 (or 4.70:1) relative to the output shaft. Now the pocket bearing is under a large load PLUS it is rotating at a different rate than the output shaft so it will be generating heat. At least there is a slight possibility of oil splashing up into there, but that bearing is really doing a lot of work in low range and it is very small and I feel it is critical to oil it. That is why Toyota put it directly in the mouth of the output shaft where the oil supply is! The only saving grace here is that in 4WD low range we are not likely to travel at speeds of over 40 mph and certainly not for an extended amount of time.
So this is probably the best situation because you are most unlikely to travel in low range at speeds over 20-25 mph? for a prolonged amount of time so the frictional heat generated will be the lowest in low range than in high range.--
I am sorry if this is very short and sweet and if I've over looked anything, I am at work and have gotten interrupted 5 or 6 times while writing this and really don't have much time to respond. Please reply back if you require further explanation and I will be able to put up a solidworks drawing of the oil ports on the factory and Marlin Crawler output shafts.
So.. wow, I actually didn't realize the problem was THIS severe until I actually thought about it and spelled it all out.
I will see if I can comment on this more later tonight or tomorrow.
Regards,
BigMike
