Originally Posted by Marlin Crawler:
On all auto chain driven and manual gear driven t/cases, if it is towed in two wheel drive, the output shaft will turn, but there will be no way for the oil at the bottom of the case to get to the top where the output shaft is. On the chain driven cases, the input shaft turns the planetary housing which drives the oil pump. Gear driven cases use the input gear and low range gears to throw oil on the inside of the housing that collects the oil via gutters and directs it to the rear of the case by gravity. Both style of cases, must have the input shaft spinning to lube the output shaft, speedo gears, and rear seal of the t/case. The rear driveshaft must be removed.
Marlin
I don't have a manual with me right now, but as I remember, according to the manual, to flat tow a Hilux with a manual trans & a gear drive t/case, shift the trans into 4th gear and shift the t/case into neutral.
This seems strange to me because without a twin stick, in order to engage neutral in the t/case, you must first engage the front output. Therefore you will put unnecessary miles on your front drive line, diff, axle seals, birfelds, etc. But it makes sense since more oil will be circulated with the addition of the front output gears moving.
You can still achieve the same effect with the t/case in neutral and the front driveline removed/disconnected.
So the best option is to put your trans in 4th gear, the t/case in neutral, and disconnect your front driveline.
Regards,
BigMike
Oh, as for dual cases, you want to keep the Crawl Box in high range. Otherwise it will multiply the movement of the transmission output shaft by its low range gear ratio, which is excessive and unnecessary.
High Range in the Crawl Box and Neutral in the t/case (which is still high range in the t/case [4WD-High])
Flat towing has no different effect to the Crawl Box compared to normal driving conditions.
OOPS says:
I would not flat tow without removing the rear d-shaft. Here is what happened to a friend of mine.
1983 Toyota on a dolly with single case, tranny in neutral, t-case in neutral. Homemade front d-shaft not balanced or perfectly straight, 83 CV on top of the front shaft, good angle on front d-shaft. We were coming back from the Dusy doing about 65 MPH and all of a sudden, the rear wheels locked up on his rig. Lucky his dad was trailer towing his Jeep so we put the Toyota on the trailer.
Even with both in neutral the front shaft still turns. What we figured happened was the CV in the front shaft came froze up causing the tranny to lock up.
Total carnage, Transmission, rear R & P, and front d-shaft.
Take the ten minutes to pull the rear d-shaft off the diff. and tie-wire it to the it to the frame.
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to go along with my earlier post and past experience, it is well worth it to just disconnect the drivelines when flat towing a crawler more than a few miles. a trailer is best, but no D shafts means waaay lower chance of breaking shit