02 Pathfinder 'auto' 4wd automatic transmission replacement

[rgk]

Well, thanks to not-the-quite-right size of hose the dummy at Auto Zone assured me would work, I dumped my trans fluid going up a mountain pass. The car was fine for about a month, but now the torque converter is failing to lock in: P0744. I am looking at replacement options.

Looking at eBay, I see that all the $300 transmissions are only good for the 2002 model year vehicles produced in 07/01. The trans that should fit in mine starts at $600 and appears to be far more rare. Any idea why this is?

Also, is it possible I just burned out my torque converter? Replacing just that would be far less expensive. Or should I not risk doing all the work of replacing it if I may have burned out the transmission as well?

[rgk]

OK, I talked to a mechanic who confirmed that the transmission is toast, figured out which transmission I need (the post 08/01 build with the electronic 'auto' shift 4x4), found one at a junkyard, and bought it for $350. A friend is picking it up this weekend, and we will swap it out next weekend. Wish us luck.

[barnaclebob]

If you could do a writeup with a couple pictures of the tricky parts that would be awesome.

[OneSpiritBrain]

How did you remove the 4H-4L linkage from the transmission?

[rgk]

OK guys, I'm back. It's been a while.

I was pretty close to selling the car. I had posted it on craigslist to see if anyone would bite. No one did, and a friend at work offered to help me swap the toasted transmission, so I took it on.

First things first: We work as part of a maintenance crew, and have a shop that I was able to use. Plenty of space, tools we can borrow, a huge 10-ton floor jack, plenty of wood to place jack stands on, and a solid, flat, indoor surface. This helped a lot.

Second, I purchased a transmission jack adapter, but it turned out to be too tall to be of any use (we weren't about to try to provide over 30" of clearance from floor to crossmember on jackstands sitting on wood blocks), so we enlisted the help of a couple of other coworkers who got under the car and helped hold the transmission in place as we aligned it and bolted it in. Without them this job would be very difficult and dangerous.

Third, I purchased two used transmissions. Why? Because the first threw codes as soon as we fired it up. After a few minutes of driving, the fluid turned pepto-pink, a sign of water or coolant in the transmission. What luck! My friend was crazy enough to want to help me do it all over again, which we did. I found another transmission on eBay for $400 with freight shipping, and so far it seems to be working well.

Some lessons learned:

1. The torque converter bolts aren't that hard to break free if you have one guy with a socket wrench on the crankshaft, and another guy on the torque converter bolts. The guy on the TC has to provide 90% of the torque, but the guy on the CS should be pushing the opposite way at the same time. This will prevent the first guy from slipping off the bolts.

2. The trans-to-engine bolts are not impossible to get to if you have a) a 17mm swivel socket, b) two long extensions, and c) a swivel coupler. You can get to them with this configuration without dropping the transmission.

3. It helps to remove the oxygen sensors and the metal trans fluid lines, but it's not impossible to do the job with them in place. I was surprised at how easily my sensors came out. Getting those metal lines in and out is a PITA.

4. Once you crack everything free, prep is really easy the second time around. However, the first time we did this job, the entire first day consisted of spraying stuff with penetrating oil and cursing bloody knuckles.

5. Be very careful with your connectors. Take your time removing them. Spray them down with contact cleaner and, if you must, be very gentle with a flathead and a pair of pliers. My second transmission arrived with one of the connectors sheared. I had to cut it off the old transmission and splice it together, which naturally made me very nervous. Those wires are awfully small and well-insulated.

6. Don't listen to the Haynes manual: it's far easier to drop the transmission and transfer case as a unit, then separate them. It was somewhat difficult separating them just on the bench.

7. Drain all your fluid, then turn your crankshaft and let more fluid drain. There is lots of fluid in your torque converter, and this slowly comes out as you turn it. Any way you slice it, you will have spills. Have plenty of cloth, cardboard, and oil soak rags on hand. Don't be macho and work with the stuff dripping on your arms and in your hair. My friend broke out really bad all over his arms and had to go to the dermatologist because it hadn't subsided for over a week. I broke out and had scabs all over my head. Let the stuff drip out overnight and don't forget to drain/fill your transfer case.

Onespiritbrain: I didn't have to, I have the electric shift.

I'll add more to this as it comes to me. Questions? Comments?

[EdBwoy]

Congrats on a successful swap.
Without including draining time, approx how long did the swap take you the 2nd time you did it?

And, I think you have really great coworkers!

[rgk]

Roughly 14 hours - 6 for removal, splitting the TC and trans, attaching the TC to the new trans, and installation. 8 hrs for setup & cleanup (exhaust, connectors, starter, driveshafts, etc., as well as jacking and physical cleanup).

[rgk]

Back from my first long drive since replacing the transmission, everything is all good until about five miles from home and the damn IACV starts acting up. Upon further inspection at home, it fries the ECU! FUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUCK!

[yngw13]

damn...hindsight give you 1000 other options...