Well, the first real modification I performed, wasn't really a modification but more like an upgrade. My 97' Cherokee, as you have read, runs power through the AW-4(Aisin-Warner). As many of you know this transmission is revered as one of the best four speeds out there. Also, as you have read, I recently had this transmission rebuilt. That was not cheap...I won't go into how much I spent, but it wasn't cheap, I'll just leave it at that. So keep reading on as I share some advice on how to keep your transmission running cooler and out of the shop for a while longer.
Let's first talk about the transmission. First off the transmission came in cherokees and comanches behind the inline 6, 4.0L. It did make an appearance in the grand cherokee in '93, also behind the 4.0L. Below is a picture of the tr
ansmission to identify it.
As you can see this is one long transmission, approximatly 25-3/8" long. With a detachable transmission to engine mount. The crank postion sensor is located on the drivers side and towards the top. The transmission is held in place by 4 grade 8 bolts, with the top 2 being star headed. There is a identifing tag on the passanger side towards the back, with numbers on it reading 30-40LE. The torque converter is a lockup style, essentially making the engine speed and the transmission rotation 1:1. The output shaft is 23 spline, on '91 to 2000, and was a 21 spline on '87 to '90.
Now that you are a little more informed about the transmission, there is one more thing that I need to inform you about. It creates excessive heat, which leads me to the reason for this upgrade. With the amount of heat this transmission creates it leads to premature ageing of parts. The fluid, which is engineered to reduce heat and create better friction between the clutches, breaks down faster thus not doing it's job and leading to the ageing of parts. So with better cooling the transmissions parts last longer thus keeping you out of the transmission shop for awhile.
The cooler kit
The cooler kit was manufactured by Imperial, and sold under the name Hayden, as the "Econo-kool" series. The manufacturer claims are that it cools 60% over stock in the most optimum position. I purchased this cooler at Advance-auto, for roughly $42 dollars. The kit came with the following:
| 1 | aluminum cooler |
| 4 | hose clamps |
| 4 | zip ties |
| 4 | foam pads |
| 1 | partial hard line |
The cooler is 12"x 8", fully soldered, aluminum cooler:
Just because I have that be prepared attitude, I went ahead and bought an extra 18" in length of 3/8"diameter transmission line. Which was good because I used all of it.
The installation
The install took maybe 30 to 45 minutes. Actually It took me a little more time but that is due to the pictures I took. Now I know you might be thinking that you have to take apart alot of things but not really. The first thing I did was remove the headlight bezels. There will be 4 screws hold those in place. The next thing I did was remove the 4 screws holding the grill in place. At this time I took notice of the original placement of the transmission cooler (outlined in red). I couldn't get a better picture, but if you can notice the condition the cooler. All those dents in the cooler do not help with air flow through the unit. Thus not allowing the fluid to be cooled efficiently. The cooler still worked, but was all jacked up, and not very efficient.
As I was removing the cooler I ran into a slight problem with the hard lines coming from the cooler. They kept getting caught on the opening they were coming from. So since I did not care if the cooler was in good condition or not, I just bent the lines enough to get the cooler out. Normally I try to save a perfectly good part, that way I could sell it and apply that money towards some other upgrade or modification. Since the cooler was old I figured I save myself some trouble and just toss it.
I did do something that might have been a problem. I cut the return line from the cooler to the transmission. This is outlined by the red box below.
Below is a close-up of the return that I cut.
As a side note most modern automatics have the fluid run through the radiator to do a pre-cool before it passes through the trans cooler. This upgrade will not affect that process and will just tie into the existing process, so no worries.
Well since I have the old cooler out I started to think about where to place new cooler. The instructions that came with cooler give some pretty good examples of where to place the cooler. They also came a little bit of information as to where the best possible places would be.
So I thought and looked around and found the spot that I felt was the best place for the new cooler. After much thought and some exaiming of where the cooling fans were. I settled on the passanger side in front of the radiator. This was where I would get the most efficiency for cooling, not only while I was driving but while I might be stopped. The fan behind the radiator is the constant spinning fan, and would draw air through the cooler and radiator constantly.
Since I located the cooler, now came the time to secure it to the car. As you can see, the zip locks run through the new cooler into and through the radiator. I found it easier to run the zip locks through the trans cooler first, kind of like drilling pilot holes. Also I had a tough time pushing the zip locks through the AC condenser. To pad the cooler against the condenser, the kit came with four foam pads with holes in the middle. I placed those in between the cooler and the condenser. They're there to just seperate the cooler from the condenser.
Once everything was installed I just had to route the incoming line and the return line. I decided to make the incoming line come in at the top of the cooler. The return line exit out the bottom. The routing was easy because the lines are flexible. The set-up is pictured below.
The Lines hook-up:
Once everything was installed up top, or front if you will. I then moved to under the vehicle. Before I detached everything, I traced the lines to and from the transmission. I then doubled checked to make sure I didn't reverse the lines. The picture to the left and in the red box is of the line from the cooler to the radiator connection.
As you can see I used one of the four hose clamps, and the transmission line that came in the kit.
The picture below is of the new connection. From the cooler to the return line to the transmission. I was a little worried about doing this since they do make connection pieces to attach the flex line to the OEM return line. It seems to be holding, with no problems.
Finishing the project:
Once everything was installed I just reversed the process of the grill and the headlight bezels. I then hopped in the truck, started it up and checked the fluid level. I also checked around the fittings and looked for leaks and anything that might still be loose. To update everyone on this upgrade, to this day I do not have any leaks. As for if this cooler is cooling the 60% over stock, that is a little hard to do right now, since we are in winter. As soon as the summer hits and we hit those 95+ degree days I'll be giving an update. By then I hope to have a trans temp gauge installed. So stay tuned for the next upgrade...
