Just a couple of things.

- The clutches in the tranny don't slip, once engaged. If they do, you have problems. They act just as a clutch with a manual tranny. They slip as they're being applied, but once applied they don't slip any more, that is they better not slip anymore.
- You really don't need a new valve body for increased pressure. Simply get a manually adjustable manual valve.
- You don't want to run the pressure up much else you risk hurting things.
- Running the pressure up a little will make the clutches apply a little faster and what you'll notice is more "crisper" shifting.
- Running a little higher pressure most likely won't really help anything, unless you're towing a lot, and heavy. The tranny shifts pretty quickly now as it is.
You most likely won't see any increase in clutch life by increasing the pressure, again, unless you're towing a lot and towing heavy.

- Try measuring the temp at the input line. This is important to see how well your tranny cooling sytem is working. We generally don't care how hot it can spike coming right out of the torque converter, but we are very interested in how the cooling system is performing. Look at the location of the sending unit for the tranny temp light.

- The temperature spikes mention here so far are 100% normal. You'll see 'em spike up when the tc is not locked as it generates a lot more heat.

- An aux cooler is always a good idea, however I don't like 'em sitting in front (or behind) the radiator blocking the airflow some. I've used before the ones with a built in, thermostatically controlled fan (B&M makes a couple of sizes of those along with a couple of other companies) and have mounted them (in the case of the Jeep) under the vehicle way out of the way of everything.
Out here in southern AZ it gets *HOT* and rockcrawling real slow really causes the tc to produce a lot of heat, and, when going really, really slowly, there isn't much air coming through the radiator as it is.

- Oil thermostats are a good thing, especially if you don't run the tranny fluid through the radiator. I didn't with the Jeep (run the ATF through the Jeep) and the B&M cooler kept it super cooler.

The trannies in XJ's (Cherokees) are A340F's. DC used them only in the XJ's for a small handful of years for reasons totally unknown, when they used non Toyota trannies for everything else for the Jeep's beginning to now.
The A340's in the XJ's are prone to failing kinda more often than they should, but all of the ones that we saw and rebuilt were from cooling (actually lack of) problems. They were simply burning them up.




Fred

 

They sell this stuff called ICE to put into your trans. don't no if it work or not. I put it in my runner, but I donot have a temp gage to see it it is doing anything or not. what do you think?

 

This depends on a few things like hydralic pressure if you dont have enough pressure and two much torque from the engine your tranny will slip and you will burn up trannies. this is the case with the supercharged 3.4.

Once again this depends on application and and the power invovled

True True

This again depends on application if you have more torque you will slip more then you should and you will have increased friction because the clutch packs will slip.

The problem with this is that you need to know what the spikes are to know whether or not you are burning your oil and there for making it not work effectivily. You could have a very large cooler and have insane tempatures precooler and have satifactory tempatures post cooler.

Even though your tranny fluid (hydraulic oil) isnt supposed to lubricate alot it will act as a friction modifier (aka lubricant) when cold because of its viscosity. If you use a Oil Thermostat, with a big enough cooler, you will keep your oil at its optimum range and you wont spike as much

the A340 isnt just limited to toyota or jeep. Isuzu used them for awhile

HMM sounds like either a lack of cooling or possibly to much torque from the 4.0L Straight 6 causing slippage




Fred[/QUOTE]

 

I have a question as to how this setup will decrease the spikes. I get the logic of it better cooling because it doesn't come in contact with the fluids that are at too high a temp. (stock radiator), Since all these temps are being seen in the hose running to the stock cooler and aftermarket cooler. I don't see how a different system will decrease the sudden spike. I can see how it could help keep the system overall cooler but I don't see how it will mellow out a spike. I can be running at 160 and spike to 210 really quick, then it cools off really quick. Don't get me wrong, I am not bagging on this setup, I am just confused how it helps with the spikes. To me it seems like the spikes are going to happen no matter how cool the tranny fluid is once it comes back to the tranny.

 

they will happen no matter how cool or hot.

but how the spikes will be mellowed is by greater cooling efficiancy if its not coming in contact with the radiator it wont take as long to cool it.

instead of using the engine coolant thermostat to keep the coolant at a constant temp. and therby being the mean that your trans oil temp is measured by. you use an oil thermostat that increases and decreases flow based on temperature. This will alow a greater temperature differential and that is the key. The spikes arent the problem really. They are natural to any automatic transmission its just the nature of the beast. its when it spikes to high or for too long. thats the bad thing.

do you see spikes in your coolant temperature when you pull a short hill no why because of 2 things volume and greater cooling efficiancy its not because the spike isnt there. just check and exhaust temp gauge. your engine temp spiked. the coolant just handles it more efficiantly and doesnt show the spike.

Check into any hydraulic system one of the key components in keeping ANY hydraulic system cool is VOLUME. this will also help to mediate spikes. not really sure on how you would increase volume on our trans' at this point though.

 

read thru this article

Gadget's 4runner
the guy that started URD

http://www.gadgetonline.com/Transmission.htm

 

The torque converter is just that. You input a shaft speed on one side and output speed and power at a diffrent setting (if its not locked up). There are a series of vanes inside (like a turbine engine) as the fluid flows past the vanes the fluid changes speed. you can harnes this change in speed to generate "more power" at a diffrent output rpm. the downside is the process isnt very efficent and puts a lot of "shear stress" on the fluid which basicly does nothing but generate heat (think of it like rubbing your hands together). Some power is "lost" to generating heat.


My question was more toward the "is this normal" than "is this a problem" as mentioned. I firmly belive that the situation is "worse" without the aftermarket cooler, so the temps we are seeing are actually better than "normal".

I think changing the valveing would work the best to keep the engine in its sweetspot for power (which my 5speed does an great job of doing on my truck with the stock setup 4.56 and 31's) Its almost like my 4runner is geared to tall (but ive never checked the door pannel gear numbers to see what its sporting... my GUESS would be 4.88)

In a perfect world it would seem a 4th gear (without OD) would be the perfect setup for having power when haulling (kicking down out of OD and not screaming at 4.5K while trying to do 70-75) and good fuel acconimy (low rpm with OD on) around town/crusin

 

This is the key part gadget talks about
See a pattern? More temp the parts are exposed too the worse, I can imagine the s/c helped contribute but it would be no better than if you trailored or hauled heavy loads or did alot of driving that ehated the a/t up.

Level 10 can do the work or IPT can, either one I can tell you is a reputable shop as I have visited and had IPT do work on my vette where they actuallyhasd to make new parts to fit my unique 4+3 trans from 84' c4' vettes. Been to level 10 for a friends firebird to rebuild and beef up his trans to make it a weekend drag car.

Both places are excellent, if your really so concerned about the temps in the A/T then pay now for the valve body work or wait and see if you need a whole trans rebuild later.

 

thanks for explaining snap-on
i had the idea right i just wasnt sure on how to explain it.

as far as O/D on when towing. thats baddddd news

there is a reason that any vehicle that has a tow/haul mode turns off the O/D when in Tow/haul mode

 

ya i edited my post... tow mode was supposed to be WITHOUT OD on (it was late lastnight )

 

well i too have an aftermarket cooler but my sender is welded into the tranny pan instead of being mounted in the hose i dont seem to have any fluctuation issues with mine, I am also not seeing the temps some of you are getting, i wanted to monitor my tranny temp because of my marlin so that was my original intention to monitor temps while crawling but mine never exceeds 170 with the exception of when it is really hot outside (80 deg or above) then it only reached around 200 deg the rest of the time it barely moves the guage under normal highway driving it hovers around 100 or so and mine is an autometer as well
i wonder why mine seems to run so cool altough i would rather it be on the cool side rather than running hot
i too have never had any overheating but i do wonder?
just my .02

 

I agree with that now that I've run an exhaust temp gauge for a few days. The EGT spikes very fast but the coolant temp is pretty stready.

 

I must be because of your sender location, the pan is a relatively big body of ATF and that would absorb the fluctuations and probably be the coolest spot in the tranny. I've heard its not a good place to monitor the tranny temp.

 

Dales, right about this the reason your not seeing is because of the volume of atf.

 

It's because that's where the returned ATF ends up.
It dumps back into the pan.

This (return line or inside the pan) is actually where we want to measure the temperature, if you have only one gauge.
We really don't care too much about spikes from the TC when it's not locked up, etc.
We do care about how well the ATF cooling system is working and that's why we want to measure the input temp.
Best would be two gauges, output and input temps, but for only gauge, measure the input temps.




Fred

 

So Fred, what temp is too hot for the return line or pan reading?

 

I would worry if I start seeing 210 + for any length of time.

Tranny fluid should be changed (just like any other lub) once a year or so, especially if you live where it's really hot (like here in southern AZ) and/or it's really dusty and/or you tow a lot (heavy towing) and/or you offroad a lot where you're crawling (as in rocks, etc)..
I also *highly* recommend running synthetic ATF, and that'll certainly extend the fluid change time. Synthetic ATF is much, much more resistant to heat (less prone to break down), however heat can and will still damage seals, etc.
If you don't run synthetic, I highly recommend running the additive Lubgard.



Fred

 

so should I move my temp sender over to the intake hose? It is currently in the output hose before any of the coolers. I am not sure if I want two tranny temp gauges. Also, I am diggin' all the good info in this thread.

 

Fred

If one puts in about 190hp into the A340H, should one get the valve body upgraded? The only towing im doing is about 1,000lbs tops. (18' aluminum boat, 40hp tiller, steel boat trailer.)

Later my goal is going to be about 250hp going in....youd definately recommend that VB upgrade then? Same possilbe towing conditions.

 

Fred, so what your saying is that as long as the temp in the pan is fine the whole thing is fine???

Because what if you have a very efficent cooler with a thermostat. your pan temp is never going to go too high unless your being really mean and rude to your transmission. but your output temp, precooler, could possibly see very very high temps. temps that would denature the Trans fluid and cause other problems. and you would never know because your cooler and thermostat are doing their job.

just to clarify 210 is very low tempature for hydraulic fluid. but this is post cooler as well, Correct Fred????

Bumpin have you read gadgets article about the VB upgrade???
has a lot of good info in it.

As far as 190hp to the A340H im doing that right now and have clean crisp shifts and towed 4000+pounds 1200 miles with the A340H. and its still clean and crisp as the day i jumped in it after the swap. now as far as the VB upgrade to it after i add the SC hmm from what ive read in gadgets article its probably a very good idea.