Car repair – Page 31 – The Jeep Guru

December 23, 2011March 26, 2012

How to Replace the Transmission in a Cadillac Catera.

The Cadillac Catera was designed a sport grand touring car. It is actually an Opel Omega built in Germany. When it was introduced, the automotive magazines sang its praises loudly. The car drives and handles well. However, they have proven to be rather high maintenance and unreliable. Also, parts are hard to get and they are expensive.

The transmission is a GM 4L30E. This same transmission is used in BMW’s and Isuzu Troopers. I found some useful information in some of the Trooper forums.

The owner of this particular Catera found a replacement transmission on ebay. I had it delivered to my office parking lot. We swapped it on to my little utility trailer in the parking lot rather than having the truck negotiate the long gravel driveway to my shop.

With the car on the lift and the battery disconnected, I began by draining the fluid. Fluid is added through a hole in the side of the pan. There is no dipstick or filler tube like on other GM transmissions. I only drained the amount that comes out when the engine is off. The level in the pan is lower when the transmission pump is running. For this reason, the transmission fluid level must be checked with the engine running. Which is interesting considering the exhaust pipe runs just a couple of inches from the fill hole.

To release the torque converter from the pressure plate, I removed the rubber plug from the bottom of the bell housing. I used a long screwdriver to slowly rotate the flex plate until a bolt was visible through the front hole. An assistant with small fingers was helpful in removing the bolts through the access hole. There are six bolts that hold the torque converter to the flex plate. They all had 15mm heads.

**See update below on turning the crank by the damper pulley bolt instead.

I next disconnected the drive shaft at the coupling. I should have dropped the exhaust pipes at this point. It would have made removing the oil cooling lines much easier. Next I disconnected the electrical connectors and the oxygen sensors and removed the exhaust pipes. Be careful with the sealing rings at the front as they are very expensive from the GM dealer if you damage one. You can likely get them cheaper at a muffler shop but I was able to reuse the ones on this car.

Note: I was later able to find the sealing rings at Advance Auto but they are marked as discontinued by Fel Pro. They we still over $20 each which seems a lot for a simple gasket.

With the pipes out of the way, disconnect the shift linkage and anything else that might be connected. You may have to cut some wire ties on the wiring harness. Next, support the transmission on a jack and remove the cross member. The transmission mount was broken on this car so the cross member fell off when the bolts to the body were removed. The body bolts had locktite on them and were very difficult to remove.

Two of the main transmission bolts come in from the front of the engine and the rest come in from the transmission side. They all had 19mm heads. There are also four small bolts that hold the bottom of the bell housing.

I removed all the bolts and carefully slid the transmission back off the dowels and let the converter nose slip out of the crank. Then I lowered it out form under the car.

I set the two transmissions side by side on the floor and made sure everything was a match. All the sensors were in place on the replacement transmission so I did not have to move any over.

I then secured the transmission on the jack and set it level as that was how the engine was sitting. The sticker on the replacement transmission warned that the front seal needed to be replaced. I did not see any evidence of leakage but I pulled the torque converter any way to see how the seal looked. Sure enough, there was a visible worn spot on the seal.

The owner picked up one at Auto Zone that did not fit. He tried to get one form the Cadillac dealer but it was going to take two weeks. We found one on ebay but I decided to try one from Advance auto. That seal was made different but fit fine. The original seal has three bolts that hold it in place. The instructions say not to drive the seal in but to use the bolts to pull it down to a seat. The replacement seal from Advance did not have the three bolt holes so I had no choice but to drive it in. I did so carefully.

[Important Update! About three months later, the pump seal popped out of place. The transmission had to be removed from the car and a new seal fitted. This time I took the time to order the correct seal form a supplier on Ebay. This seal had the correct three retaining bolt tangs on it. It may be possible to fabricate some retaining clips for the Advance Auto seal, but I think it would be better to just use the correct seal. Note: do not use a seal without some means of mechanically fastening it in place!]

I had a lot of trouble getting the torque converter indexed back on the pump drive splines. I thought I had it once but when I went to set the transmission in place, it contacted the flex plate way too soon. I had to set it back down and try again. After much spinning of the torque converter, it finally dropped into place on the cogs and then there was plenty of room.

I made sure the transmission was lined up with the engine and carefully slid it into place. Everything slid into place easily. However I took my time and made sure that the bolts drew the transmission up evenly.

Ideally you would spin the torque converter a few times to make sure it is centered in the crank before bolting it to the flex plate. However, due to the design of the bell housing, all I could do was rock it back and forth a few times. I was glad I had pre aligned one of the tabs on the converter with a hole in the flex plate because it is very difficult to turn the torque converter through the tiny access hole.

I use a magnet and a small fingered assistant to work the bolts into place. Between bolts, I again used my long screwdriver to slowly rotate the flex plate to the next position. Once they were all in, I spun it all around one more time and torqued each one down tight.

Update: I found a 16 mm 12 point socket would fit the reverse torx crank bolt and allow me to rotate the engine form the front rather than awkwardly using the screwdriver on the starter ring.

Next I reconnected the wires and the shift linkage. I then reconnected the cooling lines being careful with copper washers on the rear banjo fitting. I fitted a new mount and reattached the cross member and exhaust hanger. There is a helpful arrow on the cross member to show which way is the front.

With all the bolts in place, I then reconnected the drive shaft. I had to use a soft hammer to get the shaft to slip over the output shaft of the transmission. I did not want to try to pull it down with the coupler. The local dealer wanted $220 for the coupler, so don’t damage it.

I set the left side exhaust pipe in place and reconnected the oxygen sensors. I then dropped the oil pan and installed a new filter and gasket. It was much easier to do this job under the car than with the transmission on the floor. I reinstalled the pan and filled it with fluid. I then put up the other exhaust pipe which limits access to the fill hole.

To fill the entire transmission, the pump must be turning. That means that the engine must be running.

Based on advice from a friend, I built a device to quickly put fluid in the transmission. I used a length of ½ inch clear tubing and a gallon transmission fluid jug. I drilled a ½ hole in the cap of the bottle and slipped the hose inside and down to the bottom. I used my heat gun to help straighten the hose. I then drilled a 3/8 hole near the handle of the jug. I put fluid in the jug and slipped the hose in the fill hole. I then used my air blow gun to pressurize the jug and force the fluid up into the transmission. A quart of fluid will transfer in seconds so be careful if you use this method.

Once the transmission was filled, I plugged the hole and lowered the car. I shifted it into all the gears and drove it forward and backwards. I could hear the pump whining so I knew it still needed more fluid. I picked it back up and filled it again. It seemed to stay full after having moved all the solenoids by selecting all the gears and moving the car.

I gave it a test drive and brought it back and checked for leaks. Finding none, I drove it back to the happy owner.

See update on pump seal here

December 6, 2011

Squeaking drive belt on a Jeep Cherokee

When we rebuilt Sandy’s XJ after the engine bay fire, we installed a new Gates serpentine belt. The old belt was completely burned up so a new belt was needed no matter what.

When we started it up, there was a squeak in the belt. I took the belt off and spun all the pulleys. The idler pulley had a nasty sounding bearing, so we got a new pulley and bearing. The squeak came back after a few days.

On a return trip to the shop, I listened to all the pulleys with a stethoscope and noticed a noise in the AC clutch. Since she has not yet bought an AC condenser, I simply swapped her compressor with one I had in the shop. The compressor was bad but the clutch was still good. I had planned to install a new clutch bearing on her at a later date when she was ready to have the AC repaired.

The squeak came back the next day. I let her drive it for a while to see if it would get worse or go away. It got worse.

Back at the shop, I again removed the belt and spun all the pulleys. I even briefly ran the engine with no belt to make sure it was not the damper rubbing the cover. All the pulleys sounded fine on the stethoscope but the squeak was quite annoying. Jennifer asked if it might be the belt.

I found a used but still good belt in the shop and slipped it on for a test. The squeak was completely gone. I drove it for a day to make sure it did not return as it has in the past. On the second day, it is still quiet.

I am not sure why the new belt squeaks. I plan to try it on another XJ sometime to see if it squeaks there. But for now she has a quiet engine again.

December 5, 2011

Adding Shoulder Belts to the Rear Seat of an Early Jeep Cherokee

Shoulder straps were not available in the rear seat of a Jeep Cherokee until 1991. However the engineers who designed the body must have had them in mind from the beginning.

Scott decided to add shoulder straps to the rear seat of his 1989 Jeep Cherokee. He used belts from a 1993 donor. Removing the belts from the donor involved heating the under body nuts with a torch to allow the torx headed bolts to come loose. PB Blaster just did not loosen the rust and locktite enough to get them out with the limited torque of a torx bit.

After removing the interior panels, we found that the lower mounting points are all there in the exact same place as the 1993. The reel bolted right up and even the stabilizer tab hole is punched it the right place.

The slot that the belt passes through is there as well, however, we had to open up the front of the hole to allow the bolt to pass through without rubbing and to line up with the holes in the 1993 interior panels.

The anchor points at the roof were a bit of an oddity in this Jeep. On one side, the entire anchor point was welded in place but never tapped for threads. On the other side, the hole was punched in the sheet metal and the two plug weld holes were there, but the backing plate was not mounted.

For that side I fabricated a plate from ½ inch steel and tapped the appropriate hole in it. I also added a bolt hole to bolt it in where it would have originally been plug welded.

The mounting points under the seat are in a slightly different place than the 1993 donor. However, simply bolting the shoulder belts in where the original reels were mounted worked fine.

I was amazed that we only had to fabricate one plate and tap one hole to make this update. I really don’t understand why AMC did not offer rear shoulder belts in the early Jeeps since all the mounting points are there. Just for curiosity, we checked our 1984 parts car and found that it has the mounting points in it as well. So Jeep planned for shoulder straps all along but did not actually offer them until 1991.

Scott used the interior panels from the donor Jeep which matched the color of his older panels exactly. He had to cut two holes in the head liner to allow the roof bolts to go in but that was easy to do. He now has a nice safety update to his older XJ.

November 22, 2011January 5, 2012

Changing the Thermostat on a Jeep Cherokee

Janice’s 1999 Jeep Cherokee has had a small water leak for a few weeks now. We finally tracked it down to a leak at the thermostat housing. I decided that since I would have the housing off, I would also replace the thermostat. I decided to use the Mr. Gasket one like I put in Scott’s Wagoneer.

I had forgotten how much easier the thermostat is to access on the later model engines since I rarely work on those. On the earlier engines the belt is right in the way of accessing the bolts. On the 1999 the belt is routed differently and is not in the way at all. I did unbolt the fan shroud to get a little more working room, but I am not sure that helped much.

The housing is held to the block by two 5/16 bolts with ½ inch heads. I removed the two bolts and the housing popped right off. I had to use a screwdriver to pop the old thermostat out of the recess in the front of the block.

Cleaning the front of the block took a while. I scraped old gasket with a scraper as much as possible. I finished up with a Scotchbrite wheel in my drill. To clean the housing, I chucked the Scotchbrite wheel in my drill press and brushed the surface. I polished part of the outside of the housing while I had it in my hand.

I had a little trouble putting it all back in that the thermostat did not want to stay in the recess. I made sure that the bleed hole was rotated to the top and pressed it in. It would fall back out each time. I finally put a few dabs of RTV on the flange and got it to stick long enough to set the gasket and housing over it.

I then tightened the bolts and refastened the fan shroud. Then I put the radiator hose back on and tightened the clamp. I left the heater hose off and used a funnel to fill the head with coolant until it bubbled out the radiator cap. I then installed the heater hose and finished filling the system through the cap.

UPDATE: The new thermostat failed immediately on our Thanksgiving trip. I did not notice it until it started getting cool out and I wondered why the heater was not working. Then I noticed that the temperature was much lower than normal.

When we got back home, I pulled the thermostat and found it was stuck open. Better than stuck closed but still not acceptable. I returned it to Autozone and they swapped it for a new one with no hassle. I still had to buy another gasket to install the next one. Before installing this one, I put it in a pan of water on the stove and made sure it open and closed properly.

She says her Jeep is now running at normal temperature and the heater works again.

Update: I recently changed the thermostat on my 1991 Jeep Cherokee. The belt routing is different and makes the procedure slightly different.

Mr. Gasket PERF THERMOSTAT GM-195 – 4365

November 21, 2011December 9, 2011

Track Bar failure on the road

On the way home from the Tracy city Trail ride we had a scary incident. Jennifer was driving and I was in the back seat with the boys. Just as we entered the Ridge Cut on I-24, she screamed that the steering had quit. Luckily there was not much traffic around and she was able to coax the Jeep over to the shoulder.

I hopped out and looked under the Jeep. It did not take me long to spot the track bar drooping down. The bolt that secures it to the axle was missing. The missing bolt allowed the axle to move side to side rather than turning the wheels when the steering wheel was turned.

I rummaged around in her tool kit and finally chose a Phillips screwdriver to fill the hole. We secured the screwdriver with a bungee cord and I drove slowly to the next exit.

We drove to the nearest Ace hardware but it was closed. We went into Walgreen’s next door to look for a bolt. They did not have any bolts or anything that fit the hole better than the screwdriver we were already using. They did however have electrical tape.

I taped the screwdriver securely in place so that it would not work out as I drove. We tried to find an open parts store but since it was just after 9pm they were all closed.

I decided to slowly drive the Jeep back to my shop. It drove OK but had a lot of loose motion in the center of the steering. I had to anticipate turns and be ready.

The next morning I searched the shop and finally came up with a spare bolt and the special nut that goes on the back. I removed the screwdriver and cut of all the tape. The screwdriver was only slightly bent and I returned it to her tool kit.

I installed the new bolt and nut and torqued it to 74ft lbs per the Haynes Shop manual. While I was under there I noticed that the connection of the tie rod to the pitman arm was slightly loose as well. I removed the cotter key and turned the bolt a half turn or so to snug it up. I then put back in the key.

The steering still had a little slop so I removed the electric fan and cleaned off the adjuster bolt on top of the steering box. I tightened the box about a half turn or so on the adjuster and locked back the lock nut. Her Jeep drives much better now.