Shift kit and Trans cooler

[Farley]

I have a 99 Sport with a 3" Rusty's lift and am currently running 31x10.50's. I was thinking of adding a B&M shift kit and some type of trans cooler. I am servicing the diff's, t-case, and transmission twice a year and only use synthetic oils.

Will adding these increase the life of my tranny?

Thanks!

[89xj]

I have a 99 Sport with a 3" Rusty's lift and am currently running 31x10.50's. I was thinking of adding a B&M shift kit and some type of trans cooler. I am servicing the diff's, t-case, and transmission twice a year and only use synthetic oils.

Will adding these increase the life of my tranny?

Thanks!

whats a B&M shift kit do?

[5-90]

Does B&M make a shift kit for the AW4/A340? It's a Toyota box.

I know there's an outfit called Level Ten that does, but it must be gold, from the pricing. Besides, what about your transmission don't you like? Repair of a problem (real or percieved) requires an effective diagnosis...

As far as a cooler - that's ALWAYS a good idea for an automatic transmission. I further suggest you spend the extra dosh for the kit with the thermostatic bypass valve (B&M, Flowkooler, and a couple others make them) that will bypass the cooler until operating temperature is reached and then open to it. While you're at it, a spin-on filter setup won't go amiss, either. The OEMR filter is a metal screen, and it doesn't catch anything fine.

When you are installing the cooler, disconnect the lines to the cooler in the radiator tank. This will help keep down the operating temperature of your engine and your transmission...

5-90

[Planetcat]

5-90, are saying to have the auxilliary trans cooler be the only thing cooling the tranny and implying that hot tranny fluid running through the internal trans cooler in the radiator might actually heat up the engine rad fluid? I've had this suspicion for a long time because I overheat while towing. Sorry to hijack the thread.

When you are installing the cooler, disconnect the lines to the cooler in the radiator tank. This will help keep down the operating temperature of your engine and your transmission...

5-90

[Israel]

Yeah, I think your going to have to elaborate, 5-90. My lines are leaking to the radiator and I've been thinking throwing one of those tranny coolers in there as well as a filter when I replace the lines. Are they low enough pressure that I could cut off the fittings on the metal lines coming off the tranny, flare the ends a bit and put in new hoses with those worm gear clamps holding everything together?

If anyone has eliminated the lines to the ratiator or thrown in an auxilory cooler, please give us the details of such a project!

[5-90]

If you check around (I think Jeg's or Summit are good places to start, but I don't have my catalogues handy at the moment...) you should be able to find kits with an external cooler, a thermostatic valve, and a spin-on filter mount (or be able to assemble one farily easily.) You will want to plumb lines to the filter first, then the bypass valve, and finally the cooler - this arrangement will allow full-time filtering.

Pull out the OEM lines, and use the stubs for the rubber hose. I haven't been able to proto my fittings yet, but that should be happening soon (this quarter is almost over, but next quarter I'll be able to devote my extra shop time to other pursuits. Like this one. I've also got an idea for new manufactured NSS units floating around - should be considerably less than dealer... Or maybe parts...)

Give me a day or so, and I'll be able to get more info going. I just don't have a lot of time to-night - I'm here clearing buffers before I write a couple papers that are due to-morrow...

5-90

[Lucas]

5-90, are saying to have the auxilliary trans cooler be the only thing cooling the tranny and implying that hot tranny fluid running through the internal trans cooler in the radiator might actually heat up the engine rad fluid? .

Yes, think about it. In stock configuration, the tranny oil has only one place to dump heat, into the radiator.

[XJFREK]

I've been wondering this too. A couple years ago I had a tranny cooler installed at a towing shop. Now I wonder if I still have any fluid running through the stock cooler at all. Not trying to hijack the thread, but this is in the same vein of the original question. Now that the crimped metal fittings on the hoses are leaking, I've been thinking of replacing it. Does anyone out there running a tranny cooler have a preference? Fin and tube or the stacked plate design. Any brands to avoid? Plus, does anyone out there mount theirs someplace other than behind the grill?

[railroadjeep]

I've been told the stacked plate type dissipates the heat much much better then the tube and fin design. I run a stacked plate in my rig, it's like a 6x11x3/4 or something like that.
Mine is also plumbed still using the OEM cooler, if/when I get one of those thermostatic valves I'll ditch the in tank unit. You dont want to know the problems a leaking in tank cooler can cause with a vehicle, trans fluid and coolant do not mix well, period.

[small pederson]

dont forget to buy the B&M trans temp gauge setup :)

[bchulett]

"I was thinking of adding a B&M shift kit and some type of trans cooler. Will adding these increase the life of my tranny?"

I don't know where you found a shift kit for the AW4 ... B&M, TransGo and Level 10 that was mentioned doesn't list a kit for this application. Shift kits are commonly used to eliminate the overlap during shifts ... reducing friction and heat.

I don't think the AW4 needs a shift kit anyway ... just have the trans and t-convertor evacuated once every 50K miles.

But I definitely believe a cooler would be beneficial to extend life ... just plumb it like the factory towing package has it and you shouldn't have any under/over temperature problems.


Good luck.

[5-90]

"I was thinking of adding a B&M shift kit and some type of trans cooler. Will adding these increase the life of my tranny?"

I don't know where you found a shift kit for the AW4 ... B&M, TransGo and Level 10 that was mentioned doesn't list a kit for this application. Shift kits are commonly used to eliminate the overlap during shifts ... reducing friction and heat.

Give Level Ten a better check - you should find it listed under "Toyota", model "A340." AW4/A340 goodies aren't the easiest in the world to find... Fortunately, before AMC got the thing, it was used in the Toyota pickup, the Turbo Celica Supra, and in the van - as well as being used in RWD Lexus (overpriced Toyotas anyhow.) I remember asking L10 about Jeep-specific info, but that was a few system recoveries ago and I have long since lost the message I'd gotten back...

5-90

[gixer]

I would not bypass the stock cooler in the radiator. A friend of mine had done this and after he fried his tranny the shop said it was because he bypassed the factory cooler. From what I have heard they are to work with the factory cooler. You plum it after the factory cooler to help reduce the fluid even more than when its in the radiator. If you are going to bypass the factory cooler you need to make sure it is rather large to handle the heat and then it still might now do any better cooling than running it after the radiator. Just some food for thought.

[xjblaine]

of course they're made to work with the factory cooler, but now that I know the trans cooler is in the radiator (shiver), I'm going to look into eliminating the factory cooler and running aftermarket. I just can't get the thought of antifreeze in my transmission out of my head. I mean, I know it works just fine as an engine oil, and water is always helpful in your diffs, but I'm just not sure about using it in my tranny.

[5-90]

Properly done, bypassing the internal transmission cooler is beneficial to your engine and your transmission. You will definitely want the thermal valve for better operation - especially in cold weather or at freeway speeds - and using a cooler spec'd for an XJ or larger will do nicely.

I install an external cooler on nearly everything I own with an automatic transmission, and I don't have transmission problems. Like any other mod, if you plan before execution you should come out alright - I always have.

5-90

[gixer]

Properly done, bypassing the internal transmission cooler is beneficial to your engine and your transmission. You will definitely want the thermal valve for better operation - especially in cold weather or at freeway speeds - and using a cooler spec'd for an XJ or larger will do nicely.

I install an external cooler on nearly everything I own with an automatic transmission, and I don't have transmission problems. Like any other mod, if you plan before execution you should come out alright - I always have.

5-90

Planing is the key. You just have to make sure its large enought for the tranny. Most of the kits use one that is to small. I am not saying it wont work you just shorten the life of the tranny that is all. if you want it to bo better then you need a larget one other wise its just a wast of time and money.

[DeadEyeJ]

of course they're made to work with the factory cooler, but now that I know the trans cooler is in the radiator (shiver), I'm going to look into eliminating the factory cooler and running aftermarket. I just can't get the thought of antifreeze in my transmission out of my head. I mean, I know it works just fine as an engine oil, and water is always helpful in your diffs, but I'm just not sure about using it in my tranny.


Blaine, the antifreeze never enters your trans. Imagine putting a hot ziploc baggie full of hot water into a sink full of cold water. The 2 liquids never mix, but the cold water still cools the hot. Your factory trans cooler works much the same way. The fluids are kept seperate but their containers are in contact with eachother, so they exchange heat.

Transmissions are intended to work best when warm. The stock trans cooler actually works as a trans heater when you first start driving. I'd leave the stock cooler and run an auxilliary cooler with a thermostatic valve as 5-90 recommends. This setup will warm it up quicker AND keep it from overheating.

As far as the overheating while towing problem - it is more likely the extra work being done by the engine that is overheating your rig. Unless you have the pedal pressed down fairly far, the torque converter remains locked on your trans when you are driving at highway speeds. While it's locked it produces very little heat because there is no internal slippage (friction). The unlocking is that small shift you feel when you press the pedal down a little while driving on the freeway.

Many XJ's have overheating problems. I believe that the main problem is the dinky radiator that they come with. Many trucks have radiators nearly twice as tall as an XJ. Get an aluminum 3 row GDI radiator at autozone for like $120. It works great and has a lifetime warranty with no questions asked.

I hope some of this info helps - good luck!

Jared:patriot:

[DeadEyeJ]

So, I'm retarded. I just reread your quote up there and realized you were joking. Just ignore my first paragraph please.:anon:

[BLUTO]

Yeah, I think your going to have to elaborate, 5-90. My lines are leaking to the radiator and I've been thinking throwing one of those tranny coolers in there as well as a filter when I replace the lines. Are they low enough pressure that I could cut off the fittings on the metal lines coming off the tranny, flare the ends a bit and put in new hoses with those worm gear clamps holding everything together?

If anyone has eliminated the lines to the ratiator or thrown in an auxilory cooler, please give us the details of such a project!

I haven't looked at my Jeep in a long time (at the shop), but doesn't the tranny oil cooler lines enter the radiator thru a threaded x flared fitting? Where the fitting is male threaded into a female bore in the radiator....If so, just remove the fitting and put in a plug.
Also, remember that tranny fluid doesn't like to see temps over 175*F for long. If you send tranny fluid into a radiator that's running well over 200*F in the summer, are you really COOLING the tranny fluid? I feel that a external tranny cooler that receives good airflow, kept clean, and piped with a thermostatic bypass is the best bet for longevity in an automatic transmission. :thumbup:

BLUTO :guitar:

[DeadEyeJ]

Just food for thought -

The trans cooler is on the exit side of the radiator. That means that the 200 degree coolant has already been cooled by the radiator before it reaches the trans cooler. It should be well below 200 degrees by then. The temp gauge measures the coolant at it's hottest point - right as it exits the head.

Jared:patriot:

[xjblaine]

So, I'm retarded. I just reread your quote up there and realized you were joking. Just ignore my first paragraph please.:anon:

It's ok, I had many a retarded moment this evening putting on my RE lift..."crap, I need a spring compressor".... I was just pointing out my distaste for car companies combining systems. If there was ever a problem, trans fluid ends up in the radiator and engine....and not in the trans. and ditto about what bluto said about hot days.

[5-90]

While it's true that the transmission cooler is on the cooler side of the radiator, the XJ radiator is small enough without introducing more thermal load. That, and what if the brazing fails? The "cooler" for the transmission fluid is essentially a hollow tube (think two layers of pipe brazed together at the ends) and that's not the most efficient design.

Also, the upper fitting is a flare, the lower is usually a QD.

Considering the XJ has a tendency to run hot (I think nominal is up around 200*,) I've never been fond of running hot oil through hot water, and the internal cooler is a cheap solution to a potentially expensive problem (and the excuse "that's how everyone does it" just doesn't work with me.) The thermal valve with the external cooler is a better idea.

For the argument of the water system heating the fluid to operating temp - true, but it takes the engine a while to heat up due to the greater volume of coolant involved, so how much help is it? On some other vehicles I've had where I did the thermal valve, spin-on filter, and external cooler setup - and compared times for temperature shift - the thermal valve won out AND the engine stayed cooler the whole time. I don't have the notes, but the timing was farily significant.

So, all else being equal, I am willing to go on record saying that an external cooler with a thermal control valve is a better option than the OEM setup, and further state that modifying the system to delete the OEM internal cooler in favour of a PROPERLY CONFIGURED (it's not that difficult) external cooler setup is a better way to go - especially for a vehicle that has the potential of seeing little "ram air" cooling (think off-roading,) which will reduce the cooling efficiency of the radiator and associated systems. Even with the fans going full tilt, it's still not going to get as much air as it would at freeway speed - that's just the nature of the beast. If you are planning on off-roading extensively, I'd even go so far as to make you start thinking about an engine oil cooler, and possible a P/S cooler. Bringing the fluid temperature down on P/S (like any hydraulic system) will make it a little more consistent, and cooling the engine oil will help bring overall engine temperatures down by assisting the task of the radiator with a fluid that gets closer to the combustion process, and is directly impacted by internal friction...

5-90

[hadAjeep]

Old A/C condensors make good trans coolers. they're light, big, and made out of aluminum. If you've got the room. Never looked on an XJ, since I don't have one yet.
As far as the trans fluid and engine coolant never mixing, not true. My friends cousin was complaning about his Grand Cherokee always leaking water, and it was always full. yeah it was full of trans fluid and the trans was full of coolant. Bye-bye transmission. $2500 later he had a new trans and was back on the road. I'd run an aux cooler and disconnect it from the radiator. I'd run an oil cooler too, get's pretty hot around here.
200F is normal for an XJ? So is it the same for an MJ? My friends MJ hits 215F-220F pulling his little tent trailer up the 4 lane of the 168 going to Shaver Lake.

[scoobyxj]

would it be posable to set it up so the radiator is in the curcit untill the thermal valve opens that way you still get the quick warm up[for those of us that drive shorter distences in cold weather] and the lower cooling atvantages.

[Gojeep]

Dont forget to take into account that the bigger the auto transmission cooler or even just the more heat you remove from a cooler in front of the engine radiator, the more heat is passed onto the radiator. I also places far more resistance to the airflow passing all the way through the the cooler and the radiator especially at low speeds. There is no free lunch, the heat you removed from one area is now in another.
You be better off looking at one of those coolers that can be mounted else where like along the 'frame' rail shown in a tread the same as this before on NAXJA. I also have had great results with my deeper pan that has proved itself really well to remove the slow shifts I was getting in hot sand while towing.

[Roxtar]

While it's true that the transmission cooler is on the cooler side of the radiator, the XJ radiator is small enough without introducing more thermal load. That, and what if the brazing fails? The "cooler" for the transmission fluid is essentially a hollow tube (think two layers of pipe brazed together at the ends) and that's not the most efficient design.

Also, the upper fitting is a flare, the lower is usually a QD.

Considering the XJ has a tendency to run hot (I think nominal is up around 200*,) I've never been fond of running hot oil through hot water, and the internal cooler is a cheap solution to a potentially expensive problem (and the excuse "that's how everyone does it" just doesn't work with me.) The thermal valve with the external cooler is a better idea.

For the argument of the water system heating the fluid to operating temp - true, but it takes the engine a while to heat up due to the greater volume of coolant involved, so how much help is it? On some other vehicles I've had where I did the thermal valve, spin-on filter, and external cooler setup - and compared times for temperature shift - the thermal valve won out AND the engine stayed cooler the whole time. I don't have the notes, but the timing was farily significant.

So, all else being equal, I am willing to go on record saying that an external cooler with a thermal control valve is a better option than the OEM setup, and further state that modifying the system to delete the OEM internal cooler in favour of a PROPERLY CONFIGURED (it's not that difficult) external cooler setup is a better way to go - especially for a vehicle that has the potential of seeing little "ram air" cooling (think off-roading,) which will reduce the cooling efficiency of the radiator and associated systems. Even with the fans going full tilt, it's still not going to get as much air as it would at freeway speed - that's just the nature of the beast. If you are planning on off-roading extensively, I'd even go so far as to make you start thinking about an engine oil cooler, and possible a P/S cooler. Bringing the fluid temperature down on P/S (like any hydraulic system) will make it a little more consistent, and cooling the engine oil will help bring overall engine temperatures down by assisting the task of the radiator with a fluid that gets closer to the combustion process, and is directly impacted by internal friction...

5-90
5-90, I truly don't mean this in a smart-ass way at all. It's just that when someone is giving potentially damaging advice, particularly when it goes against conventional wisdom, I need to know their credentials. Who are you and what qualifies you in this area?

[XJ_ranger]

or buy a 5 spd...

[small pederson]

5-90, I truly don't mean this in a smart-ass way at all. It's just that when someone is giving potentially damaging advice, particularly when it goes against conventional wisdom, I need to know their credentials. Who are you and what qualifies you in this area?

how is this advice potentially damaging at all? maybe if youre a fawkin idiot you shouldnt work on your own shit cause you may damage it, sure, take it to 4 wheel parts. and how is this against conventional wisdom? im pretty sure doing most of the shit we do to our rigs is very unconventional in the wisdom department.

[Roxtar]

how is this advice potentially damaging at all? maybe if youre a fawkin idiot you shouldnt work on your own shit cause you may damage it, sure, take it to 4 wheel parts. and how is this against conventional wisdom? im pretty sure doing most of the shit we do to our rigs is very unconventional in the wisdom department.Are you kidding me here? If you can't see the potential for damage by eliminating cooling features for your transmission then you must be a XXXXin idiot. Yes, bipassing the trans cooling in your radiator does go against conventional wisdom. Don't believe me? How many people do you know who do it?
Reread my post a$$hat. I'm not saying it's wrong, I'm only asking his background to see what credibility he brings to the table. Opinions & a$$holes, everyone has them. It's up to you to see if they are full of $hit. I'm not saying he's full of $hit, But if I'm going to follow advice I want to know who's giving it.