RE4R01A

[Cuong Nguyen]

How to rebuild a RE4R01A automatic transmission. This is actually more along of a teardown procedure than a rebuild at the moment as I am inspecting the internals for damage for accessing value/cost of repair vs picking up a newer (Xterra) transmission. I'm also see if the internals can be upgrade to the "heavy duty" version of the later Xterra transmissions. Keep in mind, I'm not a professional tradesman. Just your typical average joe who likes take things apart. Pulling the guts out is a no-brainer and you really don't need a FSM for it. Where the FSM comes in handy is when you start taking apart the valve body. locations of the pins, valves, springs, spacers, washers, O-rings, seals, and different lengths of bolts is very critical so It's best to keep a "map" of where things go. Also it helps to have already taken it apart before LOL.

 

If you manage the get your input shaft jammed inside the torque converter, it's pretty likely you may have damaged your torque converter. :roll:

 

Remove the torque converter. Your input shaft should still be attached inside your transmission. Drain the fluid out of your torque converter.
Remove the input shaft by pulling it out. It kind of snaps/locks inside the transmission with a detent.
Remove the bellhousing. It's held onto the transmission by some 14mm bolts. On mine it looks like some sealant was use on the bolt shoulders to prevent fluid from leaking. Also, on mine, sealant was used on the oil pump so when I removed the bellhousing it came off stuck to the bellhousing.
This is the backside of the oilpump stuck to the bell housing:

 

needle bearings on the back side of the pump:

 

Make a note of the rubber seals here in the grooves. They are split seals so make sure you do not loose them or forget to put them back on.

 

Anyhow, if you're 2wd or 4wd, you'll need to remove the tailhousing/adapter to get access to the output shaft.

 

Make note of how the parking pawl lock, spring, pin, and spacer are oriented. Remove and keep them in a baggy.

Now remove the parking gear. It's held in place by a snap ring. You may need a small flat blade screw driver to help get it out along with your snap ring pliers. I had to but it could be that I'm using some cheap stuff. Once the snap ring is out, you can pull out the parking gear. Behind the parking gear is a small thin caged needle bearing. You'll see a lot of these later on. Remember the orientation of the bearing.

Edited March 19, 2016 by Cuong Nguyen

[Cuong Nguyen]

The FSM says something about loosening this so you can release the brake band. I kind of bypassed this and just pulled out the reverse clutch assembly out and the band just popped loose. Be sure to not lose the band retainer pin holder thing. Not sure what the FSM calls it. You can see the small thing in above the parking gear lock thing. The brake band "brakes" the drum from spinning.

 

Yeah, so this is where those bits and pieces I saw floating around in my transmission came from:

 

Missing friction material equals rivets grinding down on the reverse clutch drum. I need to find a transmission guru to pick their brains. If the band is too tight than the fluid is squeezed out of the friction material causing premature wear and possibly glazing. I imagine too lose would cause weird shifting issues. That's what the nut on the outside of the transmission case is for. There's a specific range for the tightness of the band which I will have to find somewhere.

 

So you've removed the drum which is part of the reverse clutch assembly. On the backside of the drum one of the many clutch packs of the transmission. Remove the lock ring to get access to the clutch disks. Measure thickness if you want to get an idea of how worn they are. Chunk and replace.

 

[Cuong Nguyen]

Under the gold cap that you see in the middle of the drum are a set of springs. Use a C-Clamp or suitable tool to play pressure on the cap to remove the lock ring.

The high gear clutch assembly is what fits inside the reverse clutch assembly. removing the clutch pack and innerds is the same as previous.

 

Next up, the high clutch hub which again fits inside the previous innerds.

[Cuong Nguyen]

To close up the reverse clutch assembly is the front sun gear.

 

Now for the goodies:
Front planetary carrier

[Cuong Nguyen]

Pull out the rear sun gear in the middle. This will expose the snap ring holding the output shaft. Push the output shaft from the rear towards the front of the transmission to have better access to the snap ring.

 

Looks like things were getting hot in hurrrr.

 

[Cuong Nguyen]

Pull the output shaft out through the rear.
Well that doesn't look good.

[Cuong Nguyen]

Back to the front, pull out the front internal gear, rear internal gear with the forward clutch hub, and overrun clutch hub.

[Cuong Nguyen]

[Cuong Nguyen]

[Cuong Nguyen]

]

 

Time to remove the forward clutch assembly. Look at all them clutch packs.

 

[Cuong Nguyen]

lower needling bearing and one way clutch bearing

 

[Cuong Nguyen]

Now for the low/Reverse brake assembly.
Remove retaining ring.

[Cuong Nguyen]

rearmost plate is concave. note orientation.

[Cuong Nguyen]

Comparison of the 93 4x4 valve body (left) and 02 nissan Xterra 2wd valve body (right)

 

 

you will notice that the oil pipes have less bends on the Xterra than the Pathfinder. Some oil ports are enlarged on the xterra and the solenoids are slightly different. ALso the accumulator things have a nipple for the bolt threads.

 

I'll post more later.

[Cuong Nguyen]

'93

smaller openings

 

 

'02

larger openings

 

 

older vs newer straighter tubes

 

Slightly different casting but insignificant

93 vs 02

 

 

Edited April 4, 2016 by Cuong Nguyen

[Cuong Nguyen]

upper valve bodies

93 vs 02

 

 

Accumulator springs

 

Notice 93 has one more coil than the 02.

lengths look the same not too sure about the diameter or thickness of coil.

Edited April 4, 2016 by Cuong Nguyen

[Cuong Nguyen]

Upper valve body markings 93 vs 02

 

 

 

 

 

 

[Cuong Nguyen]

lower body:

pilot filter, check valve spring, and check valve

02 Xterra valve body halves

My old gasket. I'm guessing my 93 donor transmission saw excessive heat in it's past life.

[Cuong Nguyen]

One of the gaskets: my 93 bottom and 02 xterra top

The 93 has a lot of tiny holes in the gaskets whereas the Xterra does not.

Plates are identical. Pictured is both of them atop of each other.

Only way to differentiate the two: xttera plate on top with pathfinder below

location of check valve and spring as well as the pilot filter.

Comparison of 93 vs 02 check valve.

Notice that the Xterra (right) is chamfered for improved directional flow.

[Cuong Nguyen]

upper valve body, 93 vs 02

differences:

the Xterra has an increased opening here (haven't traced the routing to where it leads and how it helps):

The xterra has deeper veins vs the 93 for the solenoids. You could dremel yours out to match the xterra.

Lower valve body comparison (93 vs 02 xterra). You can notice that the Xterra uses straight pipes with few bends.

The veins of the lower look the same between the two but I did not have the time to study them closer.

[Cuong Nguyen]

Oil pump internals

rubber seals on the actuator arm

 

the backside of the arm. Gary over at AAA-1 says that the arm will develop a sharp edge which will cause sticking. He suggest to file it down.

where the arm rubs down on

 

This spring is under a good amount of tension. Be very careful when removing it. I almost lost the metal tab.

input shafts are the same. 93 vs 02. Disregard the bluing on the Xterra shaft. It was a junkyard spare.

 

This is why my input shaft was stuck. I still can't figure out how it happened.

[Cuong Nguyen]

Inside the torque converter
impeller on the left and my stuck input shaft inside the turbine

 

Picture of the stator. You can see the snap ring which holds the sets of bearings together.

 

backside of the turbine and gear which locks into the clutch.

 

clutch.
each spring you see has two smaller ones inside of it.

 

[Slartibartfast]

I have no plans to take one of these apart but I'm following this thread anyway! Thanks for documenting the teardown.

[Cuong Nguyen]

I ran into a snag a while back. I didn't have an accurate way of measuring endplay so I spent a whole day trying to come up with something and yet couldn't get an accurate measurement.

I wished I had kept the broken thrust washer so I knew what I had in their prior to teardown. Regardless, I still had to fork out $125 dollars for this simple gauge to measure endplay.

I placed the order yesterday so I should be getting the new race and thrust washer next week.

 

 

 

Bearing race measurement

 

Clearance for thrust washer

 

 

Calculating my options.

[Cuong Nguyen]

Well after calling around it looks like Nissan discontinued the pump bearing race 31429-21X03 and others of that series. So your best bet is online transmission parts sellers. I was lucky and found one at Cobratransmission.com. I hope they have as their website lists it and my transaction went through.