Aw4 power handling/ reliablity and performance upgrades.

[NorCalChris]

As I'm in the process of accumilating parts for my 4.7 stroker, I started wondering how much power can the aw4 tranny handle reliably? Im just planning on throwing a little over 300hp and 350ft/lbs at it. My current aw4 has 270k on it, my last one had 250k on it. No problems except what I thought to be a worn TCC on my first one.
But back to my question, how much is too much for a stock AW4? What can we do to beef them up? Kevlar clutches? Higher line pressures? Is it just more reasonable to do a swap.....say a 700R4? Well heres what I found........
What is it?
Its made by Aisin Warner. In our jeeps its called the AW4. It also comes in Toyotas, Lexus, Izuzu's, and Volvos under different names and in different variations. A variation was used in Toyotas up to 2004. Most common name is A340. In the Toyota Supra world the A340E in the NA (naturally aspirated) Supra's is said to not handle more then 325-350hp but the A340E behind the TT (twin-turbo) Supra's can handle 425-450HP. These numbers are with based on having a good cooler installed.

THE DIFFERENCES
Taken from this write up

TT Auto
- HP Limit -425-450 w/ a good cooler.
- Valve body has 4 solenoids, the 4th solenoid controls line pressure electronically. This allows smoother shift modulation.
- Has a larger torque converter that is more efficient.
- Driveshaft bolts onto the transmission to a 3 bolt flange. (sounds like a SYE to me!)
- Has a different input shaft than the n/a tranny.
- Has more clutch packs than the n/a auto.
- Valve body solenoids activate linearly allowing more precise transmission control.

N/A Auto
- HP Limit : ~325-350 w/ a good cooler
- Transmission line pressure is controlled by a cable and only has 3 solenoids in the valve body.
- Has a slip type tailshaft housing for the driveshaft. Driveshaft slips into the transmission itself. (sounds like a stock AW4 to me!)
- Valve body solenoids have an on and off activation."

So what does this mean to us Jeepers? Well, I'm not exactly sure. Haha. The A340E Behind the TT Supras can be swaped into a NA Supra with a A340E. You need to swap the valve body, mechanical line pressure cable, and solenoids. That being said you will gain extra clutch packs and an estimated power handling of 425-450hp. So if the A340 and AW4 are the same tranny we should be able to do the same, but with A340E internals from a TT Supra.

Performance Upgrades
So with all these different versions of this transmission there has to be
some aftermarket performance upgrades. It seems no matter what you do, you need a good tranny cooler. The stock unit isnt very large at all. A quick trip to Summit Racing and you can order yourself a brand new larger tranny cooler to help keep the fluid cool. On Go-Jeeps's website he has a write-up on making a larger tranny pan for more fluid capacity. I read the Toyota Supra guys swap pans with 4runner's. I'm not sure if this would work for us or not and if so how much larger the pan may be?

Import Performance Trans sells performance AW4 transmissions and states a 50% increase in holding power in 3rd gear due to extra clutches. Costs: $3275
They also sell a performance AW4 rebuild kit which includes their "6 friction disk C-2 clutch pack for a 50% increase in third gear holding capacity"
Cost: $658
IPT's transmission and rebuild kit state that they have a 50% increase in third gear holding capacity. One big difference between the TT and NA A340E trannies was mainly extra clutches.

Here's a modified valve body for a A340E. Id call and check to see if it will work with a AW4 or not.

I found this article on Supraforums.com on how to make your A340/AW4 last. It talks sbout how you can shim the accumulators. Which will allow quicker shifts, and by doing so, reduce the amount of time the clutch packs slip and therefore creating less heat. Not super necesary for the slow rock crawling type, but this can be useful for the street jeepers and jeepspeed go-fast junkies.

Shift Controllers
RADesigns Makes a few different shift controllers for the AW4/A340. http://radesignsproducts.com/14Shiftcontrollers.aspx

I know a user on here (BrettM) used to make shift controllers. I believe he has quit making them now. Heres a write up I found, I dont know who to credit with this because I read it was miscredited already. http://www.greatlakesxj.com/tech/aw4shiftmod.html

Weaknesses
The biggest weakness in the AW4/A340 tranny is the clutches. Second weak link is the 2nd gear sprags. Third Is the stock tranny cooler.
The clutches hold up fine for stock power ratings, but when we start making more power they just dont want to hold. The second gear sprags can break from hard 1-2 shifts. And our fluid can break down quick when it overheats. The little cooler is fine for normal useage, but when we add larger tires, start towing heavy loads or up steep hills, start building power with our strokers, it just doesnt have the ability to cool properly.


More info
Heres some links to good info about the A340/aw4 transmission.

Found this link over on Pirate4x4.
A340 Transmission issues and FAQs

This one is a Transtec article posted here on from CRASH
Auto trans tech for the geeky engineer types (like me)
It explains the evolution of the A340 transmission and has some very good information. Deffinetly worth reading if you have the time.

Heres some general AW4 knowledge from Novak
http://www.jeepforum.com/wiki/index.php/AW4


--------NorCalChris

 

[badron]

DAM norcalchris you did you home work. Way to go.

 

[NorCalChris]

Lol. Im a little obsessive.

 

[egotripp]

Subscribed for future reference.:yelclap:

 

[Boostwerks.com]

Well done. FWIW, my stock AW4 seems to be holding up just fine with 8lbs of boost (knock on wood). I'd personally MUCH rather have a manual (NV4500) but the AW4 is nice offroad. I would more than likely swap it out though if it ends up bitting the dust.

 

[bjoehandley]

Subscribed for future reference.:yelclap:

Ditto!

 

[casual]

norcalchris you've helped me out the past few days, so let me try to return the favor.
If the trans in the N/A Supra is the same as the IS300, let me say mine help up to 512whp & 483wtq on 91oct. & meth(w/dyno sheets) and daily drove on 408whp & 376wtq for over 2 years.
All I had was a Ebay valvebody upgrade & a trans cooler. The valvebody upgrade consisted of 3 longer steel rods to replace the shorter ones. I did it in my driveway in a couple hours. I had a QSV (quick spool valve) & had full boost by 2900-ishrpm with a PT67. I'm sure that put more stain on the trans & she held it all without a hickup!

Those IS3's sure were cheap to build lol. Theres turbo kits out for like $1500-$1800 & it includes everything you need,unless you want 450+whp then you need injectors & something to tune with!
The 2jz-ge could handle 400-450 all day stock bottom end, throw in the 2jz-gte bottom end & your good for 750-800 all day! Although 1 guy made 1017whp in his Supra with a completly stock motor & a big single.

 

[Mesh]

I rebuilt my transmission when I did my 4.7L and it burned up after a year or two. I’m currently on a stock transmission it’s working for now but has a lot less power. With proper cooling I think the AW4 can handle the larger engine but to get the most out of it the transmission will need some serious upgrades.

Now that you’ve read every AW4 article on the internet what direction are you thinking about going in?

 

[5-90]

The main enemy of the AW4/A340 (or, for that matter, all slushboxen!) is heat. Keep the head down, and you'll keep the life up.

That being said, I'm sure there are a few things that can be done to make the AW4 beefier, but I've not seen a need. I'd compare it favourably to the THM700R4/4L60, and (from what I've seen inside the thing,) I'd consider it close to the THM350 - with the added benefit of an overdrive range (GM later added an O/D to the THM400 to make the 4L80, and ChryCo added it to the A727 to make the 47Rx. I don't recall what Ford called the C6 with OD - the AOD? I'd have to check my notes...)

I've put an AW4 through abuse I wouldn't even consider with the THM700R4 - and it kept coming back. The only reason I needed to open up the AW4 in my 87 beyond fluid changes was because three bellhousing screws fell out, the fourth had backed out about a half-inch, and the first planetary set ended up tilted in the case bore enough to become wedged in place (I had to disassemble the transmission with a Sawzall.)

I picked up a junkyard unit, opened it up, and inspected it. Took the best parts from the two transmissions (the clutches in the repple were shot, but mine were fine. The valve body in the repple was cleaner) and assembled one good one - then proceeded to put a good 100K on it, until I blew the #6 rod out the driver's side of the block when the oil pump failed at 70mph in third gear (I was on a winding road, and wanted to preserve response. So, I locked out overdrive.)

From what I've been told, the AW4 doesn't respond well to a hobbyist overhaul - but I didn't have any trouble. I think it's generally a lack of experience, from what I've been able to determine - the AW4 is one of the simpler slushboxen I've been in, but that doesn't make it a beginner's job. (I used to do the THM350/400, A727, PowerGlide, and Ford C6 for street/strip guys 'way back when, so it wasn't my first.)

Apart from that, the typical cautions apply - keep everyting clean enough to cook on, and take pictures of the valve body before you dump the check balls & springs out of it (the manual isn't always right. A Polaroid or a digital camera should be part of your transmission overhaul kit.)

Overhaul kits come with parts you don't use - the same kit usually, for instance, contains gaskets for all variations of the A340/AW4/30-40 slushbox. The primary thing you'll have extra is the valve body gaskets - make sure you use the right ones, because they are different!

One site I didn't see in your notes - the first one I found, when I was curious about such things - was Level Ten (www.levelten.com.) I believe they actually have some AW4 mods specifically intended for Jeep applications, so you may want to check them out. However, you seem to have uncovered information I hadn't so far - so I'm going to sub to this thread anyhow and add it to my Archives...

 

[NorCalChris]

I rebuilt my transmission when I did my 4.7L and it burned up after a year or two. I’m currently on a stock transmission it’s working for now but has a lot less power. With proper cooling I think the AW4 can handle the larger engine but to get the most out of it the transmission will need some serious upgrades.

Now that you’ve read every AW4 article on the internet what direction are you thinking about going in?

Well Im not done researching. But if I had my motor done and ready to go, I'd buy the ITP rebuild kit & valve body and a new oem torque converter and rebuild my tranny. Install a trans temp gauge, Install fittings into the tranny to delete the quick disconnects and run a cooler thats at least twice the size of the oem unit. If your A/c doesnt work consider removing the Condensor to get it out from blocking airflow.

If I didnt have the money for a full rebuilld Id upgrade fittings and cooler, temp gauge, and then shim the accumilators, just be carefull doing so and read the write up 5 times first.

The main enemy of the AW4/A340 (or, for that matter, all slushboxen!) is heat. Keep the head down, and you'll keep the life up.
One site I didn't see in your notes - the first one I found, when I was curious about such things - was Level Ten (www.levelten.com.) I believe they actually have some AW4 mods specifically intended for Jeep applications, so you may want to check them out. However, you seem to have uncovered information I hadn't so far - so I'm going to sub to this thread anyhow and add it to my Archives...

x5000 on keeping the heat down.

As far as my notes go, there was several things I have left out due to the lack of credibility. I did read about level ten, but heard more bad then good. If you have had a different experience please let us know.

 

[CherBear]

I feel this should be a sticky.

 

[GrimmJeeper]

One site I didn't see in your notes - the first one I found, when I was curious about such things - was Level Ten (www.levelten.com.) I believe they actually have some AW4 mods specifically intended for Jeep applications, so you may want to check them out. However, you seem to have uncovered information I hadn't so far - so I'm going to sub to this thread anyhow and add it to my Archives...

On a side note, Levelten transmission "rebuilt" a dodge trans for my buddies drag truck and sent it back to him, and it started slipping pretty badly almost immediately. Inside was all the stock parts which were supposed to be replaced with billet parts and upgraded clutches. They eventually returned his money but it was a huge ordeal.

I wouldn't put too much faith in them.

 

[NorCalChris]

On a side note, Levelten transmission "rebuilt" a dodge trans for my buddies drag truck and sent it back to him, and it started slipping pretty badly almost immediately. Inside was all the stock parts which were supposed to be replaced with billet parts and upgraded clutches. They eventually returned his money but it was a huge ordeal.

I wouldn't put too much faith in them.

this coincides with the storied I read on their A340 builds. Thats why I didnt mention them when I did the write up.

 

[5-90]

I feel this should be a sticky.

You know what - so do I. Done.

And as far as Level Ten goes - I haven't had anything done by them or gotten anything from them, I just wanted to mention them for the sake of completion. Since we seem to be getting a number of negative reports from the field, I'm rather glad I did - it could save other people dropping money that would be better spent elsewhere!

The only work I'd had done on any AW4 I owned was work I did myself (even made the special tools so I could do the jobs,) and I didn't find it that difficult.

However, "for the sake of completion" on a writeup does include mentioning a vendor that has generated consistent negative press as well as vendors that generate significant positive press - mankind is the only animal that is able to effectively learn from the mistakes of others (if we have a mind to...)

 

[NorCalChris]

=] my first sticky! I just smiled like a little school girl. lol

 

[child9]

It may be better to use a JDM A340e from a Toyota Aristo (2JZGTE powered Lexus GS300). It is even closer to the Jeep AW4 than the Supra version.

 

[Mesh]

=] my first sticky! I just smiled like a little school girl. lol

It's not only your first sticky it's the first sticky for the Street and Performance forum.

If you have the money and go with the IPT parts you might as well send in your old torque converter to be customized. I'm currently sitting on an IPT rebuild kit and and just moved into a place with a garage maybe I’ll start building up my spare transmission.

 

[5-90]

=] my first sticky! I just smiled like a little school girl. lol

So happy to help - and I could hear you giggling all the way over here...

If it makes you feel any better, I was halfway considering sticking this thread before I read CherBear's post - once I saw that, it pulled me off of the fence.

 

[XJLI]

It may be better to use a JDM A340e from a Toyota Aristo (2JZGTE powered Lexus GS300). It is even closer to the Jeep AW4 than the Supra version.

how so?

and whats the availability like on them? i've never bothered to look anything like this up on say jhot or whatever those other jdm importing sites are. i'm def interested in building/getting a faster shifting aw4 in the future.

 

[Talyn]

There are also modifications that can be done to the PCM to firm up shifts. When I had my PCM flashed they turned torque management off and turned stall torque off. This resulted in firmer shifts and a more connected feel. I am not 100% what these features do, but since its in the PCM (not TCM) I would think that TCM sends a signal to the PCM to reduce engine output during shifts.