Tranny leak after emergency stop

Abbylind · Oct 21, 2018

My M1008 had been running great. The other night I was forced to lock up the brakes when a semi turned in my path. Everything seemed fine but a day later I noticed an "oily" spray on the tailgate. A day later the truck started shifting strange and wouldnt move forward after stopping until I revved the engine. Limped it home and noticed it was leaking ATF around the rear of the tranny and transfer case. Would a quick stop (no impact) cause the seal between the transfer case and the tranny to break loose? Maybe cracked the adaptor for the transfer case?

TIA

nyoffroad · Oct 21, 2018

I doubt that the stop had any thing to do with it but it's possible. More than likely it's just been a leak waiting to happen.

Chaski · Oct 21, 2018

Clean the daylights out of it and go crack hunting. Transfer case adaptors and transmission cases are known to crack.

MarcusOReallyus · Oct 21, 2018

It could have been on the edge and the shifting weight put it over the edge. What kind of shape are your mounts in?

Abbylind · Oct 22, 2018

I though the same (motor or transfer case mounts bad) Ill crawl under there and take a gander when I get back.....

Tinstar · Oct 23, 2018

You just scared the fluid out of it.........

Abbylind · Oct 26, 2018

Ha! Gave it the squirts!

CUCV1008 · Nov 12, 2018

OP, did you find the cause? My transmission is exhibiting the same symptoms.

Abbylind · Nov 12, 2018

No joy yet...Truck is in NM... Im in Fla...I'll take a gander at it when I get back

Abbylind · Jan 17, 2019

I came home and took a gander at the tranny. It appears the leak is coming from the rubber hose connecting line that goes from the transmission to the coolant lines. imagine it would wear out after 33 years!
Anyone know what type of rubber hose to use? Fuel line ok?

TIA

ehuppert · Jan 17, 2019

Do NOT use fuel line... Gates makes transmission rubber hose, 27058 for the 5/16. We usaully get it in the 3 foot blister pack. Rated for temp and pressure. Fuel line will work for a while, then it won't!

I'm in the middle of running new steel lines, but not sure if the factory cucv stuff is 3*8 or 5*16. Fittings on the trans take 5*16 tube fittings

edit/add

With that said, Truck should have steel lines from transmission to radiator....

Abbylind · Jan 17, 2019

Thanks. Yes the lines are steel from the radiator to the transmission, however one line terminates with a rubber hose secured with a hose clamp......

MarcusOReallyus · Jan 17, 2019

That's not original, but it's not a problem. Transmission rated hose will last a long time. Do yourself a favor and get new clamps while you're at it.

Abbylind · Jan 17, 2019

Will do thanks!

Abbylind · Jan 17, 2019

I figured out why the lines are terminated in rubber hoses. Years ago the transmission housing cracked due to a bent drive shaft. The repair shop couldnt find the same type th400 housing so the cooler lines were modified to fit the new housing

MarcusOReallyus · Jan 19, 2019

Cool. Now ya know. That's good for peace of mind.

Abbylind · Jan 20, 2019

The plot thickens! The snow melted enough and I threw a tarp under the truck and crawled underneath. What I thought were rubber lines were in fact the metal cooling lines covered in grease and mud! I wiped them clean and lo and behold one of the lines had rubbed through where the cooling line clamp attaches to the rear of the oil pan. I dont know if the clamp was rubber lined but mine was metal on metal and wore two grooves in the line. The clamp had also worn through.
So Ill order 2 new lines and a rubber lined clamp....

cucvrus · Jan 20, 2019

You can piece the line with a double flair fitting. Even a compression fitting will work. That is your call. Then just split some 3/8" fuel line and add it to the outside. that will cushion the clamp and protect the line. Bending mew lines isn't all that bad. Getting them back where they belong is the best way to get it done. I like the steel lines. Good Luck. I think you have it under control.

Abbylind · Jan 20, 2019

Thanks Dr. I think I may have to go that route. I'm having a devil of a time finding replacement lines. Are those lines 3/8" OD or 5/16"?

cucvrus · Jan 20, 2019

My guess would be 5/16" due to the fact that a 1/2" crows foot wrench will loosen and tighten the fittings in the transmission case and radiator cooler. 3/8" is 9/16". That is an easy fix. 1/2 hour and report back. Thank you. Good Luck.

Tranny leak after emergency stop

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