A couple of weeks ago, my 2001 Rodeo Sport (2wd) started leaking transmission fluid. The leak came on fast and it was leaking quite a bit of fluid. In my case, I left my house in Boulder with no leak and when I arrived at my workshop in Broomfield (30 minutes away), it was leaking enough to leave 4" diameter spots in the driveway. I noticed it because it was snowy and I saw the red dots in the snow.
After peeking up under the truck, I decided it was the accumulator piston cover that was leaking:
Here's how I went about replacing the piston cover:
1. Compress the cover and spring:
The accumulator cover has a large spring behind it that presses the cover into a snap ring. That snap ring is all that holds the cover in place. To remove the snap ring, though, the spring must be lightly compressed. There are a number of ways to achieve this but I chose to make a small compressor which pushes the cover inward by leveraging the frame. Here's what I came up with:
To compress the accumulator cover into its bore, I pushed the socket against the seal and then wedged the block of wood against the frame. I tightened the nut nearest the block of wood to lengthen the rod and compress the spring. I compressed mine until there was about 1/8" between the snap ring and the accumulator cover.
To keep the block of wood from sliding, I used a wood clamp tightened onto the frame. But this wasn't really necessary.
2. Remove the Snap Ring (this is the hardest part of the whole job):
Once the accumulator cover is pressed inward, the snap ring will be free to move. Before trying to get a pair of pliers in there, use a flat-blade screwdriver and rotate the snap ring in its bore until the two holes on the ring are at the 9 O'clock position. This is the only place with enough clearance to get the pliers in and remove the ring. It took me an hour of frustration to figure this one out. Once the snap ring was in the correct position, I then used a pair of snap ring pliers to remove the snap ring:
With the snap ring removed, I removed the homemade spring compressor. At this point, before removing the accumulator cover, I thoroughly cleaned the area and bore with paper towels and solvent to minimize the chances of dirt getting into the transmission. I also used some 400 grit wet-or-dry sandpaper to clean up the area and remove any burrs or corrosion. This will help prevent damage to the new cover during installation. Here's how things looked with the snap ring removed and the bore cleaned up:
3. Remove the accumulator cover:
To remove the accumulator cover, I used a blind bearing puller. This was recommended in a thread on an online forum I frequent, planetisuzoo.com, and I thought it good advice. This particular set was purchased on Amazon for under $30.
I used the third largest collet as it fit best. I greased up its internals and slid it into the center of the accumulator cover and then tightened it down firmly. This provided a good grip on the cover.
Unfortunately, there isn't enough room near the accumulator cover to actually use the slide hammer. Instead, I opted to use the slide portion as a handle. I disassembled the slide and removed the hammer, leaving only the threaded rod. I then fed that through the passenger side wheel well and tightened it onto the collet. This gave me something to grasp.
I gave the handle a firm pull and the cover popped out, spurting out about 1/4 quart of transmission fluid with it. The spring remained inside the bore. The accumulator cover popped free with some force and I caught myself in the chin with the front fender . . . ouch!
Here's the blind bearing puller and seal as removed. Hopefully this will clarify how the tool was used:
4. Install the new cover:
With the accumulator cover removed, I used a lot of paper towel and solvent to clean the bore and the area surrounding it, ensuring that there was absolutely no dirt or gunk inside the bore or in the snap ring groove. I then liberally coated the bore with fresh transmission fluid.
I also cleaned the spring and snap ring and sat them aside. Here's the spring, new seal and snap ring. The seal I'm using is an aftermarket seal but seems on-par with the original GM part quality wise.
I coated the outside edge of the new accumulator cover with transmission fluid, inserted the spring and then slid the cover in place. The cover will fit almost entirely into the bore before the spring begins to compress. This allowed me to install the spring compressor without fear of the new cover falling out. Here's mine, sitting in place:
5. Compress the spring and new cover:
To install the new cover fully, I inserted the socket end of the homemade compressor tool into the center of the new seal and then wedged the wood block against the frame. I tightened the nut nearest the wood block until the cover was set in about 1/8" behind the snap ring groove:
6. Install the snap ring:
With the new cover pressed into place, I positioned the snap ring so that it's holes are at the 9 O'clock position and pressed the snap ring into the bore as far as I could by hand. I then used snap ring pliers to compress the spring and push it into its groove. I confirmed it was seated by rotating it around with a flat blade screwdriver.
Once the new cover was installed, I started the truck up and let it idle while I cleaned up. When the main pan was warm to the touch, I topped up the fluid using a transfer pump. It took about 1/2 quart to fill the pan.
I drove the truck back to Boulder when done and, so far, no signs of a fluid leak are present. I'll give it a few hundred miles and report back. Stay tuned. . .