4R70W non-functional on high incline

[chuzie]

My trusty 4R70W has served me quite well over the years. Just got back from Moab and, for the first time, experienced a situation I did not like at all.

I was on an obstacle with a very high incline angle and lost power in all gears. I shifted from D to R to 2 to 1, gave it gas and got nothing. After winching up and level, it worked great. Happened again later in the day on another high incline obstacle.

The fluid level is fine, so I'm wondering what could be causing this to occur. On an incline, all the fluid is certainly in the pan so I don't see the incline starving the pump pickup, right?

Looking for enlightenment and guidance please.

Yes, I know I should get a manual transmission and never worry about this again. Let's just assume I'm stubborn as hell for the sake of argument.

Thanks,
Mike

 

[DirtDonk]

Well, I'd be kind of stubborn too, now that I've experienced the joys of the wonderful 4R70W myself.
Sure sounds like fluid starvation to me. Is it possible for the fluid pick up to drop down out of the transmission body and then be sucking air? I've heard of it on other transmissions, but not sure about this one.
When a C4 does it it's usually low on fluid, or something wrong with the pick up tube. Seems like that's what I remember the discussions about anyway.

Good luck! That would suck!

 

[Broncobowsher]

Fluid starve is the only thing it could be. The pump was sucking air. Why was it sucking air? Steeper climb than you have ever had before? Transmission service and the filter isn't pulling fluid the same as before? Knock the filter out of the valve body? Sucks air sooner?

 

[Rustytruck]

probably tranny fluid running out of the pan and ending in the Tranny adapter. C-4 will do this too. Ford used the deep pan pick-up to help but doesnt solve the issue. I have seen the results of this happening at Los Coyotes Indian reservation over 20 years ago. nasty slam down the hill. Goes up so far then free fall backwards. But this is some really steep vertical stuff going up hill. very nice guy with a great Bronco his nick name was Tiger.

 

[chuzie]

Sounds like I need to drop the pan and look at ways to modify the pickup tube.

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[reamer]

Is tranny fluid SUPPOSE to leak into the adapter? I seem to have tranny fluid dripping off the transfer case...

 

[chuzie]

Not this ZF adapter, if my memory serves, we have a seal in the front that protects both the sealed bearing and the D20 from ATF.

 

[Broncobowsher]

I have seen the seal fall out in the transfer case adaptor. Is the transfer case now overfilled and red?

 

[chuzie]

No. That's the first thing I checked. Somehow that darn seal has held up very well.

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[Viperwolf1]

Could be as simple as the wrong filter for the pan. Early filters didn't have the pickup tube built in.

 

[chuzie]

Well crap. Now I absolutely have to go look!

That might be the cleanest transmission I've ever seen!

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[Broncobowsher]

Some filter kits probably lack that extension. That way they will fit either oil pan.
From what I remember the car pans have the flat bottom, they make nice trays. The truck pans have the bump and the extension.

 

[Madgyver]

Some filter kits probably lack that extension. That way they will fit either oil pan.
From what I remember the car pans have the flat bottom, they make nice trays. The truck pans have the bump and the extension.

where can I get a truck pan? and what applications/years should I look for?

 

[Viperwolf1]

where can I get a truck pan? and what applications/years should I look for?

Just about anything that had a 4R70 or 4R75 after 1993. Or you can buy a new Dorman #265-813.

 

[Broncobowsher]

Explorers have the dimpled truck pan. Mustangs have the flat bottom pan.
I will guess that most 4R70W will have the truck pan. There really isn't anything special about it. If there is the bump in the bottom of the pan, that is it. If it is flat, it isn't.

 

[Dannyboy71]

Very, informative thread for me, my filter does not have that extended tube. Does anybody happen to have a part number?

 

[pbwcr]

Just go to NAPA and buy a 4x4 filter that came with your trans, then measure to see if it fits your pan.

 

[chuzie]

Here it is. Filter has a pickup tube integrated. Are you saying there's another variant with a longer tube?

Btw, pan is dimpled for tube.



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[Broncobowsher]

Don't know of any taller than that.

 

[chuzie]

Well i guess I'll dissect filter.
Other than that, I'm at a loss.

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