Deep tranny pan part number

[Jim M]

I'm looking into an A/T swap for my 4 banger TJ. Without a deep sump pan this would be a useless and frustrating swap. I found on Mopar's site part number "P4007886 A-904 and A-999 non-chrome". Is this the same part as those with the 999 use? The description states it is for use in a RWD application and I want to be sure. I didn't see a separate application for the 4WD listed.

Any other info about the 904 tranny would be appreciated. This is a swap that I plan on tackling over the next year or so. Nothing is immediate as I still need the TJ as a daily driver and 4 angry squirrels behind and A/T pulling a heavy TJ would make for a long day. Also the 4.88's would limit my top speed to about 60 mph at about 3200 RPM!

[karstman]

Here is some limited info on what jeeps the 904 was used in.

http://www.off-road.com/jeep/tech/trans/tf904.html

Sorry I don't have any other info. I was just looking up some info on 999's last week and happen to remember the site.

mark'

[TObject]

I came to think that deep automatic transmission pan mod is useless and potentially harmful.

I never hit the regular pan hard. The deep pan is all dinged. And if one day I put a sizable ding where the fluid pickup extender is, I am gonna ether crack the extender at the top and make the transmission suck air, or restrict the pickup of fluid; both of which are harmful to the transmission.

[Jim M]

Sergey,

It would be more harmful to cook the fluid or to dry up the converter on a steep hill, would it not? I have witnessed fluid starvation in a TF99 and it sucked. All the guy could do was back down from the obstacle and go around. I'm not a "go around" kind of guy. Admittedly he sat at a pretty steep angle for quite a while as the person in front of him was clearing the next obstacle, but without that deep pan for fluid his YJ was useless. If I switch from my beloved manual tranny, the slushbox better work as advertised or I'll be quite unhappy.

Sounds like it's time for another skid for your TJ!

[TObject]

What does the deep transmission pan mod have to do with preventing fluid starvation other than the damaged deep pan is more likely to cause one?

[Robert J. Yates]

You can always just overfill the tranny if you are worried about the deep pan getting snagged and cavitation of ATF.

Me, I will run the deep pan with a skid - I have had 1 experience to many with cavitation

[TObject]

Well, bigger pan allows for more fluid, and it has larger surface area therefore it helps to keep lower ATF temperature in turn reducing cavitation. I think that similar or even better effect can be achieved with addition of extra automatic transmission fluid cooler.

Cavitation happens when pressurized ATF enters the torque converter, it then may start boiling because of the lower local pressure and high speed. When ATF boils, the vapor bubbles mix with the fluid.

Overfilling the tranny should help to reduce cavitation, since it would cause higher fluid pressure. But, how much can you overfill it before you blow up a seal or something? I wouldn?t do it. I?d say a transmission cooler it the best way to go.

[Jim M]

See, this is why people like M/T's. I don't have to overfill it, I don't worry about cavitation, I don't overheat it, and I don't have to ask any questions about it. It's simple and it will get me off the trail even if I have a hole in the bottom of it and lose 5 gears, and the clutch cable breaks. Simple. Torque application sucks, but it's simple.

So far I have one person telling me that the deep pan has nothing to do with fluid starvation, one person telling me to overfill the pan, and a link that contains bad info (the 904/909's I've seen are all 21 splines in and out, not 23). I still have no confirmation of the part number. I read all about how much better the A/T is on the rocks (and I agree) and how people with M/T's just have some ego thing going and therefore defend them, but when I ask a simple question I can't get a simple answer. Even the off topic lines about cavitation get multiple theories. Is there some sort of consensus on this? I?m trying to learn about A/T?s as they have always been a mystery to me. I?ve been inside of M/T?s, but never an A/T, so please pardon my ignorance.

The "givens" are this: I will add a cooler, at least aftermarket, and possibly in the factory radiator locations as well; there will be a skid to protect the pan. All I want is an A/T that won't overheat and won't cavitate or be starved for fluid when climbing steep rocks. Can the 904/909 be made to fit the bill? If not I'll move on to another plan and look for an alternative. Surely someone must know this information.

The end goal is to move my whole drive train forward about 6 inches. Due to the flat skid and the proximity of the M/T shifter to the tub, I cannot fabricate a way to shift gears. Wanting an A/T anyway, this would solve the whole how to shift thing. Since the A/T is cable shifted, there should be no big issues.

[TObject]

I searched Internet for 15 minutes, and the only mentioning of a cavitation induced problem in automatic transmissions I found was caused by a clogged cooler line.

I never had cavitation problems with my transmission deep pan or not.

Every time, somebody had transmission problems on a run I participated, it was a manual transmission equipped jeep.

[William]

Originally posted by TObject
What does the deep transmission pan mod have to do with preventing fluid starvation other than the damaged deep pan is more likely to cause one?

Sergey,

You're also the guy who smashed his oil pan ABOVE THE AXLE. How you did that, I don't know. A deep only hangs down a little bit more than stock. two inches at best. If you have a full length engine skid it's not an issue.

I can explain it simple:

I go up hill: on hill, my tranny goes to nuetral. I almost roll backwards down hill.

Robert has same problem. Get's deep pan. Problem gone.

I fill up tranny above max. Go up hill. Have same problem.

I put on deep pan. No more problem.

How, well, deep pan apperenty provides enough excess fluid that when the tranny is in a semi up right posistion, the fuild runs to the back of the tranny. With the old, you could put it below the sump tube. With the deep pan and excess oil, you've got enough that it remains above the sump at excesssive angles. It'd be easier to draw pictures. But I can't post them.

Don't also forget that the deep pan has a drain plug so you can service the auto tranny with out dropping the pan each time. Bonus #2.

[Robert J. Yates]

Originally posted by Jim M
See, this is why people like M/T's. I don't have to overfill it, I don't worry about cavitation, I don't overheat it, and I don't have to ask any questions about it. It's simple and it will get me off the trail even if I have a hole in the bottom of it and lose 5 gears, and the clutch cable breaks. Simple. Torque application sucks, but it's simple.

Easy Jim - while these can be issues with the auto, proper set-up and maintenance reduces them to almost a point of insignificance. Let me see if I can help steer you in the right direction or at least help you find the info you are looking for.

To start off with, the 904/909 is a light to medium duty tranny that is a decendent of the old torquflite series. They are quite robust although my understanding is that the 904/909 series will not put up with much more than your 4 banger. For that it is plenty strong and durable but if you are planning an eventual engine swap, it might pay to look into that now. The 4 banger from what I understand has a strange bellhousing bolt pattern and that will prevent anything other than the 904/909 being bolted up to it.

[i
Sofar I have one person telling me that the deep pan has nothing to do with fluid starvation, one person telling me to overfill the pan, and a link that contains bad info (the 904/909's I've seen are all 21 splines in and out, not 23). I still have no confirmation of the part number. I read all about how much better the A/T is on the rocks (and I agree) and how people with M/T's just have some ego thing going and therefore defend them, but when I ask a simple question I can't get a simple answer. Even the off topic lines about cavitation get multiple theories. Is there some sort of consensus on this? I?m trying to learn about A/T?s as they have always been a mystery to me. I?ve been inside of M/T?s, but never an A/T, so please pardon my ignorance.

I wish I had a part number handy at work but I don't. If your dealer has one in stock, its a relatively simple thing to check - the deep pan is a good 1.5" more in height than the stocker. If you can visually look at it and the parts guy can confirm it as a 904/909 application - then you have your answer.

As for getting simple answers, I have found that there is so much mis-information out there behind the auto that I tend to just learn stuff on my own using my experiences and those of folks I know and trust. I guess that is one of the reasons I get all invovled in the auto vs manual issue so heavily - I have the experience to talk about it whereas most idiots don't and simply pass along gobble-dy-gook.

RE: Cavitation. It appears that it is tranny based more than situational. Some guys never have experienced it with simply the stock pan in place and then others like me have had to get their seat fabric surgically removed from their ass after a particularly harrowing experience with it. My own thoughts based on my experiences are that it is not simply related to one aspect of tranny operation such as line pressure or pick-up point but rather that it is a combination of those factors which are determined by its build quality. I think we can all agree that there is a tolerance variation in production and I think that variation is responsible for differing opinions and experiences.

[i]
The "givens" are this: I will add a cooler, at least aftermarket, and possibly in the factory radiator locations as well; there will be a skid to protect the pan. All I want is an A/T that won't overheat and won't cavitate or be starved for fluid when climbing steep rocks. Can the 904/909 be made to fit the bill? If not I'll move on to another plan and look for an alternative. Surely someone must know this information.

Now, the various models of tranny and motors aside, if I were you, I would get a 3 core metal radiator with the built in cooler and then also add an aftermarket cooler on the return line from the radiator. I would also get a deep pan so that you can run even more fluid. My experiences with the aftermarket cooler and the deep pan is that I have had no further instances of cavitation and the additional 2+ quarts plus more surface area (cooler) will only serve tranny longevity in a positive manner. My experiences lead me to believe that overheating these trannys while possible, just doesn't occur that often in Jeeps if there is good build planning and maintenance going on.

As for overfilling it and blowing seals, I have experience there as well. I think adding a pint to the standard pan will not do anything for seal life nor will it **** out the vent and most likely it may solve the cavitation issue too. Now if you were to overfill it to the point where it was routinely ****ing out the vent, then I would say yes you will eventually have a problem with seal life but then again, who really knows. Jason Bunch at Tri County Gear told me, after I paid him for the deep pan, that all he does with his TJ is overfill it a pint or 2 and that he has never had a problem - go figure. Even stranger, right now after a rebuild of my tranny (due to the afore mentioned seals blowing resulting from a bad Teralow) I am actually running a pint lower than I could with my deep pan but I have yet to have a problem. Now, the tranny was gone through completely and it actually works better than it did new, so who knows what the issue originally was a result of.

I do run a tranny cooler and I also upgraded to a 3 core all metal radiator. I never really had a tranny over heating problem but my TJ has run on the warm side since new and that has sent me in search of how to build more cooling reserve into my rig. I want it to run at 210 all the time and I am about there. The tranny cooler made a bit of difference but the switch to the new radiator made a huge and very noticable difference.

HTH with your questions. Don't sweat it is my advice - you will learn to really appreciate the benefits of the auto once you get it installed and get your rig on the rocks. There are enough 4 banger barbie Jeeps running around out here on the pavement that will never see dirt so that tells me that the swap is plenty doable with no major durability issues.

[William]

Originally posted by Jim M
I?ve been inside of M/T?s, but never an A/T, so please pardon my ignorance.

The fact you are asking question says to me you are not ignorant. You are only being open minded. Please send me an email to wkarstens@noris.psasd.navy.mil and I will scan and send you a picture to explain cavitation in a basic way (that befits my poor mechanical knowledge) it may help, it may not. But, at least I can try.

[TObject]

William, send me a copy of the picture about cavitation too.

And if you have time also a picture that explains fluid starvation relieve of the deep pan mod.

Thanks!

[TJRON]

Sergey,
I have witnessed autos without deep pans on the steep slick rock at Moab. As William says, the problem shows up at the worst possible place. You can't go forword for quit a few seconds and you surely don't want to back down with your front wheels barely touching the rock!
Keep the deep pan and put a skid plate on it....

[TObject]

Ok fine, I?ll keep the deep pan (for now). But I still want to see the picture.

[Art Welch]

Damn you guys are civil, for a minute there I thought this was going to degrade into a JU style auto vs manual pi**ing match! I'm glad that it didn't.

[TObject]

Yep. This is a deep-pan vs. regular pan pi**ing match. Not many of those are on JU, is there?

[William]

Would you rather have a deep pan with **** in it, or a shallow pan with **** in it Art?

Of course, if I could remember right, you don't have a pan at all, eh?

[Art Welch]

Originally posted by William
Would you rather have a deep pan with **** in it, or a shallow pan with **** in it Art?

Of course, if I could remember right, you don't have a pan at all, eh?

I hope to not require any pan for my **** for many many years to come!

[Jim M]

Thanks for the input. It is sincerely appreciated. Robert, your thoughts are always welcome, especially when they come from experience. William, please send what you have to jim@jdmccabe.com. I'll also send you an email. Sergey, thanks for the link. That article was very interesting reading and I learned quite a bit from it. Art, this isn't JU, that?s why I like it. Opinions differ, but people are civil. I would rather have a disagreement and settle it with facts and arguments than resort to personal attacks and childish drivel.

[mrblaine]

Jim, et al- it is going to be gobbley gook until you have experience with it. Therein lies the crux of this little problem.

The experiences vary. Until Brad Bell starved his and found neutral the hard way, I would have stated emphatically that the deep pan was an across the board fix. When it happened, I turned to Brad and told him there was a neat little fix for his problem. He told me that he did indeed have the deep pan. We then checked his fluid level and it was a smidge low. Topped it off and then some and the problem went away.


Sergey never found neutral with a stock pan. Robert, William, Garry, and I did. I put one on Kathryn's just to be safe.

Robert runs his low, I run mine a tad high. If Robert were to run a little lower gear, I would venture a guess that he would not need quite so much reserve. He says that it has always run hot, but that is fairly anomalous. I would still like to see what lower gears do.

Garry and I run temp gauges and both of us have found that unless you are running in non lock-up mode racing up hills, the tranny never gets close to running past 190 degrees.

I also run a cooler, but not for the tranny. I am trying to build some more reserve into the cooling system overall. Were it not for the desert I play in frequently, I wouldn't even bother.

Once you start playing with one, get accustomed to it, it pretty much fades into obscurity as something to worry about.

Confused yet? As an aside, Sergey also managed to kill a perfectly fine D-44. He has ruined an oil pan and is the only one in the group to ever break a small Warn hub. Garry has managed to break a CTM u-joint. I ruined a brand spanky new 3 core brass and copper radiator after about 300 hundred yards of trail. I also have to my credit a ruined 37" MT/R with less than 2 miles on it.

We all have our quirks and a few inconsistencies with our auto trannies will hopefully not be held against us or the tranny.

[TObject]

Difference between regular and deep pan explained. [Joke]

[Paradiddle]

Okay - so I have the most excellent japanese AW4 in my XJ.

Do I need a deep pan as well? Any of you bus drivers with the auto have issues?

I'd rather pop for a few bucks now and get a deep pan then have it not work right on the trail.

I already have the factory cooler on the trans.

Jeff

[Brad Kilby]

Jim, the deep pans can be purchased in either bare metal or chrome. When it says non-chrome, it's talking about the finish of the pan. Yes, the P4007886 non-chrome pan will fit the A-999. So will the chrome version for that matter. The RWD generally includes the 4wd rigs.

FYI, I run the 4.0, auto and 4.88's. At 3200 rpm, I'd say I'm running more like 70 mph, not 60. Don't know if your 4 squirrels can get your Jeep moving that fast but my rpm and your rpm (4.0 vs. 2.5) shouldn't be any different.

Btw, this website has real nice prices on pans. Beats the crud out of my prices.
https://www.jimsautoparts.com/autotransmp.htm

[Jim M]

Brad,

Thanks a bunch. That's exactly the confirmation I was looking for. MY little 2.5 has a hard time with anything over 55 mph. The wind resistance of a lifted TJ is comparable to that of a wall. The A/T swap will happen once the TJ is retired from DD duty, so highway travel will become severely limited. Odd about your speed versus Rpm, I was driving along yesterday in 4th (1:1) and at indicated 60 mph I was turning ~3100 rpm. My speedo may be off just a tick though. Not to worry, the TJ cruises at 65 max due to safety concerns over being able to stop.

It appears that I now need to start sourcing a tranny and all the shifter parts. I just took a new job and will have my free time severely curtailed for a while so all projects are on hold. My wife will be thrilled that I'm buying parts that I don't plan on installing for months. Oh well, it's my Jeep thing, she'll never understand.

The final question I have is over the ECM. Do I need anew computer for the A/T? To be honest I'm not even sure where or who to ask to find out. Any help with that would be appreciated.

[Robert J. Yates]

You do not need the ECM but you will need to rig a switch up to engage the lock up function for the torque convertor. Search JU for StealthTJ - he is located in Tucson AZ if I recall correctly, and he is in the middle of swapping out the AX-15 for the auto in his Jeep. He can probably clue you in more on the specifics of the lock up issue.

One of these days I will get a lower gear set in my diffs, OK BLAINE lol