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Installing a Qualife Differential


Disclaimer these are only instructions, I am not liable for your Mistakes that may lead to any accidents, death or serious injury. The transmission weighs well over 100Lbs, if you cant lift it be very careful and ask for assistance. Be safe and read carefully prior to disassembling.

Prior to installing the qualife you will need the following items:

  • bearings you need 2 of them, 38440-96E00
  • Nissan part #32701-03E01 (speedometer drive gear)
  • differential seals #s are 38342-81X01 and 38342-81x00. Yes they are different, not sure what the input or gear selector seals are.
  • shims total parts from the dealer with discount $174.00 including the two $7.00 shims
  • tools that you will need. You will need a precision gauge that reads in the .001 you can get this gauge from sears. Cost is $32.00 with tax. The gauge has a needle and it moves up and down.
  • Magnetic base and this you can get from go to the search section and type in Magnetic base, or you can see if they have the actual store in your state. This magnetic base I went searching for dam nearly the whole day and no one could figure out what it was and where could pick one up. They are fairly cheap. I paid $13.00 and change for my since they had a local store near my house and yes they are open on Sundays.
  • Note keep in mind these idiots at harbor freight tools take forever to ship it will take over two weeks to get your stuff in so giving everyone heads up, I ordered my stuff 10 days ago and to this day I have not received my precision gauge and I ended up purchasing the precision gauge from sears
  • Permagrey
  • If you so desire I picked up a metal garage frame bracket with circles on it to bolt it up to the tranny to take the measurement. That was only$8.00
  • 12MM socket, 14MM socket and a 10MM socket
  • some shop towels
  • torque wrench, metal hammer, some white out to mark some areas or parts where parts go, Crowbar , a Bench Vise or a impact wrench to remove the bolts from the final drive gear<------- very important tools

Remove the 12MM bolts that surround the tranny
Remove the 14MM bolts they are short and they have a spring and checkball

grab your crow bar or what ever tool you decide to use and pry open the tranny

This is what the spring and checkballs look like

Remove the 10mm speedo gear sensor and pull it out


Now stand the tranny up and down as if it was on the car. (grab your brother sister cousin or gay friend or what ever you have to assist you to hold the tranny while you work the final gear off at an angle) now pull on the gears/ forks, now you should have enough space to work the stock differential out it will take about 3-5 mins be patient it will slide off.

Grab your new bearings and install the bearings, look at your stock differential make the qualife look exactly alike as seen on the next picture with the bearings and the speedo sensor gear. I used the old bearing seat and hit the new bearing in there with a metal hammer

Install the bearings first and then go on ahead and get the old bearing races off and install the new races that came with the bearings on the transmission case. The metal thing under the bearing is the race, Ensure the races are properly seated all the way down it is very very important


Remove the final gear, you will need a impact wrench or vise grip to remove these bolts they are very tight and install the final gear on the qualife as seen below

Now after you installed the bearing races and slid the qualife back in place install all the 12MM bolts and in place and torque them down to 18-19lbs of torque. Grab your garage bracket and bolt it onto the tranny grab your magnetic base with your gauge mounted on and set it on top of the bearing and zero it

It should look something like this

Slide the tranny to the side of the work bench and push up and look at your gauge. Do it ten times using the same amount of force. I got a measurement of 24 which equals =.0240 measure it ten times. I got out of hand and measured it more like 15 times just for peace of mind. Now look at your FSM and see what shims you need order them.


Pic of the quaife in its new home

While you wait on your shims prep your tranny to get assembled. That you can move the yellow gear thing left and right and that it is not stuck in gear. If it is stuck in gear pull or push on the forks. REFER TO FSM PAGE MT-40 ASSEMBLY

These are the three forks if you push and pull on them they will lock/unlock the tranny in/out gear. You should be able to move the yellow tranny lever left and right like it was in neutral pay very close attention Leave the tranny between 1st and 2nd gear, that is what the FSM says just do it or you will be dropping your tranny like I did.


I threaded this bolt on there. This bolt will bolt up from the out side of the case so line it up, once it is lined up the case will slide smoothly on there.

After you align the above piece and have installed your shims and seated your races in and left the tranny between 1s and 2nd gear clean on the clean surfaced that you just cleaned out apply 1/8 permagrey all around the tranny case

Here it is the two pics above you can use a piece of hanger and look for the little threaded section and install the 12mm bolt on there. Ensure you put some permgrey on this bolt


Here is the bolt ready to be installed

Bolt has threaded you can even pull on it, don?t forget the permagrey

Now grab the two springs and check balls


Push the check ball in there

Grab the spring push it in there

Clean these 14mm bolts clean them out and put some permagrey and install them right behind the spring see the spring sticking out push it and put these short bolts on there


There you should be done

You should be done by now ensure you tighten all the 12MM bolts and once you tilt your tranny up and down you don?t have to worry about the tranny locking up in gear it is only while is laying down. Trust me on this one. Torque all your 12MM bolts and it will take 24 hours for the permagrey to cure you should be good by now.

I want to thank God for giving me wisdom and physical strength to do this mod. I also want to thank my 14 year old brother for his help, Matt Pelto for the help and Delio, SprintMax, Eric Wong and Briguy for his outstanding shortcut and Ramius for informing me about the short cut and everyone that contributed to the replacement of my new tranny and quaife mod.

This is the type of garage bracket I used to bolt up the magnetic base to the tranny

Pic of the gauge, it is blurry you can see it is on zero

Gauge mounted on magnetic base

Size of bracket used 1-1/2x36??

Magnetic base on with gauge mounted

Another magnetic base pic

Another magnetic base pic

Jaime Rodriguez Jay25