What's new
  • If you registered but have not received your email confirmation check your Spam folder. If it's not there please Contact Us and let us know your username.

Flat towing a gear drive t case question

Clb

another toyota from P.R.K
CAL4
Joined
May 19, 2020
Member Number
32
Messages
1,829
Location
Envision Proofreading. first 50 club
Yes I read marlins "must disconnect driveline" 18-20 years ago....
did I mention Old guy???
then big mike (off site and about other topics) said some factory service bulletin said no need...

So to the question!
What gets fubared if you don't disco. The driveline in a set of duals?
I need to get an order in and pray its "IN STOCK" so I can have it here before I finish grenading mine.
Due to I forgot to pull the d.l. And towed out from buck island to wentwort with a busted timing chain , then stuffed it in the barn 5 years ago.
rolled...um no wheeled a taco in between.
New engine is done, but its rumbling in there (quiet before).
Thanx for any help!
 
Last edited:

Aisin

Grumpy old fuck
Joined
May 19, 2020
Member Number
304
Messages
1,358
The t case only gets oiling if the input shaft is spinning. With the driveshaft connected the output is still turning. Not a good thing to have. I had a conversation about this with Bobby Long about 14 or 15 years ago.
 

Clb

another toyota from P.R.K
CAL4
Joined
May 19, 2020
Member Number
32
Messages
1,829
Location
Envision Proofreading. first 50 club
That's apparent from the noise (new cases built -10k ago) then this issue .
seems the factory service bullitens were not Crystal clear.
Sorta like the "does the gear oil flow thru from t case to crawl box" question that gets both answers !
not having a case in front of me to dry read the process that's why I asked I know someone has had the issue before.
Fun how tech gets read and digested.
Let's see how this thread shakes out.
Thanx fer lookin in!
 
Last edited:

Provience

Kill!
Joined
Jul 8, 2009
Member Number
15
Messages
8,023
Location
Thurston County, WA
i'm also old and have flat towed before, super easy to disconnect rear driveline.

although, i did it once with a broken front hub, got to where i was going a few hundred miles later and the front driveshaft only had 1 bolt left :eek:
 

Provience

Kill!
Joined
Jul 8, 2009
Member Number
15
Messages
8,023
Location
Thurston County, WA
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.

-------------------


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
 

Provience

Kill!
Joined
Jul 8, 2009
Member Number
15
Messages
8,023
Location
Thurston County, WA
Back to the shop to make some tear down space...
last time I asked sales they went blank!
Ummm we can sell you a rebuild kit...


unfortunately, there is no easy guarantee for what will shit the bed. Easiest thing to do would be order a full rebuild kit and replace everything.

cheapest thing to do would be to tear it down, inspect everything, and clean it up and replace the bearings and shafts and gears that are bad
 
  • Like
Reactions: Clb

Clb

another toyota from P.R.K
CAL4
Joined
May 19, 2020
Member Number
32
Messages
1,829
Location
Envision Proofreading. first 50 club
Thanx
Fukk I h8 forgetting important tech stuff!

Pulled the cases out.
Gunna post the part #'s later..

The pn snafu is set. The box # is not Toyota pn.
The lookup seems different according to the bearing supply houses.
 
Last edited:

PAE

🚨 King of the Who ?🚨 
Joined
May 19, 2020
Member Number
114
Messages
1,814
Location
I live in my body, Do you live outside of yours ?
I suppose ill be looking for hubs and double end spline axles for my OH SEVEN.

OR just drive slugs for the Dana 80¿?

That will do the same as dropping the driveline yeah.

ETA: More pics of my tow bar adapter.

KMqoZVs.jpg


fRaY7NU.jpg
 
Last edited:
IH Parts America - CPT Crawler Proven Technology

Register to get rid of these ads:

Register to get rid of this ad:

Top