Power Loss on Vertical?

[IZwack]

So today I made it out to some dirt to check out the rebuilt shocks and the front Aussie Locker.

During the front locker test, the vehicle was quite in a vertical (thats the almost-flat ground in the background):

A few seconds later..

The vehicle was crawling up the face very slowly just to not stress anything and I noticed that the transmission felt like it all of the sudden disconnected - as if all of the fluid had drained out of the torque converter. Is this what had happened? I have never done anything so vertical yet so I have never experienced this before.

 

[MountaineerGreen]

I think 410 had trouble like that in the BII, all the trans fluid went to the back of the pan. But he had a custom trans pan. You may need a custom deep sump pan and pickup.

I would think you could make that with a TIG welder and some ingenuity.

 

[DB_1]

I was having that problem too with my tranny (5r55e) on steep inclines. It would slip into neutral and also out of 4wd...not a good feeling depending on the situation. I put in a PML deep pan and overfilled it a bit and it seems to be much better now.

 

[IZwack]

Interesting, so the issue is the pickup on the transmission pan.

 

[MountaineerGreen]

I was thinking, couldn't you take your stock pan, cut a portion out, extend it down 1 or 2 inches, and fab up a custom pickup tube. I wouldn't be that hard to do I wouldn't think.

 

[IZwack]

I think that would work.

Does anyone have a picture of the "pickup" -- its been a long time since I dropped the pan.

One thing I'm trying not to do is make the pan lower because, other than the catalytic converter (sohc engine), the pan is already pretty low. So my focus is to see if there's any way to prevent the pickup from sucking up just air.


DB1 >> what is PML?

 

[Jefe]

DB1 >> what is PML?

http://www.yourcovers.com/

I also had problems with that on my 5R. I fixed it the hard way though. :

 

[glfredrick]

You don't have a "pick up" per se in your automatic transmission pan. It is just a flat-mounted filter on the valve body.

If you have the factory 4x4 pan, then that filter MAY have an extension tube to rest in the dimple at the bottom of the pan. I say MAY because I've found that a lot of shops substitute a 2-wheel drive filter for the 4x4 piece when they do a filter change.

I've been kicking around a couple different ideas about pan/pickup design for steep hills (incline and decline, but incline is more critical). There is no easy solution. If you make the pan pick up from the rear, it will almost certainly run dry on hard braking and/or downhill sections. Making a pickup that "follows" the oil would be tough.

Some have advocated running a very shallow stock pan, and overfilling as the answer. For me, the jury is still out on that one. Seems like more oil and some way of getting that oil into the pickup is a better solution. I'm considering cutting up a pan and making a sump of some sort, that runs to the back of the pan, then making a pickup that can draw from that sump.

 

[gijoecam]

This has got me thinkin: Has anyone ever seen a clunk-tank used in RC airplanes? The pickup for the fuel is on e weight on a piece of flexible hose. When the plane inverts, the fuel (and the weighted end of the pickup tube) drops to the top of the tank and stays in the fuel.

I wonder if it'd be possible to design something similar for the trans pan?? Maybe a swiveling arm that pivots to the front or back of the pan as necessary (inverted probably isn't a necessity, but how cool would it be to dribe the wheels when yo're on your lid??)

-Joe

 

[IZwack]

This has got me thinkin: Has anyone ever seen a clunk-tank used in RC airplanes? The pickup for the fuel is on e weight on a piece of flexible hose. When the plane inverts, the fuel (and the weighted end of the pickup tube) drops to the top of the tank and stays in the fuel.

I used to fly RC planes and thats exactly what I had in mind in this thread.
I just wonder what size of a "clunk" one would need due to the high-volume fluid draw in a transmission.

 

[glfredrick]

I used to fly RC planes and thats exactly what I had in mind in this thread.
I just wonder what size of a "clunk" one would need due to the high-volume fluid draw in a transmission.

The actual suction line into the transmission is generally about 5/8" or so - some are 3/4" and some a bit smaller. I'd think that something along that size range would work as long as it wasn't too long (no room to get TOO long inside the pan anyway).

I'm not sure what sort of material would be that large, yet remain flexible enough to make the swing inside a pan -- AND -- withstand collapse when it acts as a suction line.

Wonder what would happen if the filter itself was drilled, and sunk to the bottom of a deep pan? The pick up is generally at the rear of the transmission, and the filter often swaps ends with the oil, picking it out of the pan at the front of the filter. It would need some stand-offs to keep the filter from sucking to the bottom of the pan.

 

[410Fortune]

With a stock 4x4 pan, filter, and the correct amount of ATF you should not have this issue.
did you check the fluid level?
Do you have an OEM style trans filter?

I ran into this on Launching pad in Moab, NOT FUN. I got 1/2 way up the obstacle like 3 times and BAM no gear...backing down was pretty hairy
I added ATF 3 seperate times until I was well over the correct level, I finally made it up and over on the 4th attempt by giving it ALOT more gas then I would have liked to

this was with an A4LD and the aftermarket pan, the company redeisnged the 4x4 version of their pan because of this problem, and I never had the issue again. I also never had that issue with the factory A4LD 4x4 pan (built in sump)

I have not had that problem with the V8 transmission either
I think the factory setup should allow pretty damn steep climbs without the trans scavenging for fluid, as long as you have the correct fluid level and filter.

 

[Spas]

but how cool would it be to dribe the wheels when yo're on your lid??)

-Joe

Not that I think it's a good idea to try this... but if you do, Iz, let me know cuz I wanna be there to see that!

*pats Morgan's manual shift knob*

I had that problem with Shelby's a4ld on wompum at Paragon a few times. I'd just put a little extra trans fluid in and it seemed to do the trick. Of course it would leak back out again eventually since first gens are the devil...

 

[Bent Bolt]

Wow, that quite the climb !! A manual trans would solve that problem.........: .

Some good ideas here about the sump problem. If you want a higher tech solution, how about a dry sump system like an race car engine??? Never seen or heard of one for a trans but I don't see why it wouldn't work. Might be more expensive and troublesome than what's needed tho.

 

[FROADER]

It happened to me a couple time in Moab, going up Dump Bump.

 

[gijoecam]

As for the clunk tank idea, an RC tank uses a piece of flexible hose. I was thinking more along the lines of a pivoting rigid pickup that swung horizontally in an arc from the front to the rear. (I've seen similar setups in underwater applications... picture a standard 90 degree JIC fitting before it's tightened down) However, the more I think about it, the less I see it being possible. That arc would cause problems.... say the tube pivoted on the right, and swung front to back along the left side of the sump. That's all fine and dandy when going up and down the hills, but then, what happens when you're off-camber leaning to the right?? All the fluid sloshes to the right side, the pickup goes either front or back, and it's sucking air again.

Hadn't thought much about a dry sump system, but that's got me thinkin' now..... That could work, but you'd have to find an electric pump capable of moving a sufficient amount of oil, weld at least four pickups onto the pan plumbed together into a positive displacement pump with the same number of stages as you have pickups, you'd need a pretty large catch-tank to dump it all into and separate the air from the oil (readily available from Summit Racing, but can certainly be made in the garage... I've done it) and then you'd need to plumb it all back into the pickup. Seems a bit over-complicated, but would definately work.

What about not necessarily a dry sump system necessarily, but a wet sump with a fluid accumulator and a check valve? Might not be ideal, but it would have to be tee-d in in-line between the transmission pump and the rest of the trans, so I'm not so sure that's even do-able. You also would only beable to feed the trans via the accumulator for a finite period of time, so that could prove to be an issue...

The more I think about it, the more I'm starting to like the dry sump idea.... anybody know what kind of fluid volume the trans pumps out at wide open throttle?

-Joe

 

[glfredrick]

All good ideas -- but probably overkill for most applications.

I'm thinking that we mainly need to do some bench testing with a transmission (seal up the front and rear with block-off plates or something) to see how much angle does what to the oil supply.

Taking an old pan and cutting a window into it lengthwise (glue in a piece of plexi) so that you could see the oil level as you move it up and down would greatly enlighten the discussion.

Likely, only a properly designed sump would be enough to take care of most of our needs.

It is possible to plumb an accumulator into an auto tranny -- just tap into the test port that goes to the torque converter. That would be the most simple way to do it, but I'm wondering if we could supply volume enough for an entire hill climb... Accumulators are typically used in oiling systems for the half second or so of oil psi loss while under G force around a corner, acceleration, or braking.

 

[GJarrett]

I had long ago heard of this happening from several people with 5r55e's like mine so I've always kept mine a little overfilled with ATF - from 1/2 to one quart over - whenever fourwheeling and I've never had it happen to me. With that transmission, maybe that's all it takes to fix the problem.

 

[Jefe]

I had long ago heard of this happening from several people with 5r55e's like mine so I've always kept mine a little overfilled with ATF - from 1/2 to one quart over - whenever fourwheeling and I've never had it happen to me. With that transmission, maybe that's all it takes to fix the problem.

I agree that as long as you have the correct 4x4 filter in place, and you have it a hair over-full (measuring it the proper way, with the engine running, and the transmission fluid warm) then you should not have this problem.
At a worst case scenario, you could try extending the 4x4 filter pickup down further, so that its 1/4" from the bottom of the pan.
The A4LD families 4x4 pan and pickup is much better designed for off-angle use than my 700R4 and I don't have any problems.