Differential size and axle spline count

Hey I need some help please! I have a 2004 toyota tacoma regular cab 2.7 liter automatic 4wd base model and i was wanting to know if yall knew what size the rear differential is ? I heard it was a 8" but then I heard some people call it a 8.4" but idk that's why I'm here lol. I was wondering what the spline count is on the rear axle to ? I would appreciate the help! I was goin to buy a powertrax lock - right locker.

 

you got an open diff, it’s a 8.4”

30 spline

 

I agree with 02hilux, it sounds like you've got an 8.4" diff, but to add a little more info...

1st gen Tacomas with a factory e-locker have what's commonly known as an 8.0" diff.
1st gen Tacomas without a factory e-locker have what's commonly known as an 8.4" diff. Technically the ring gear in the 8.4" diff measures 8.0", but everybody still knows it as the 8.4".

 

Ok so I need to get the 8.4" 30 spline lock right locker. Do yall think these powertrax lockers are worth the money ? I found one for 300$. I really want a detroit trutrac locker but dang your talkin almost 700$... have any of yall had any experience with these 2 lockers ? I'm just not sure if I'm gna like all that clicking noise from the lock right locker. Thanks I appreciate it!

 

Did you ever wind up figuring it out or ordering a certain part. I have a 2009 base that I’ve narrowed down to i think having the 8.4 open diff, im reading different things about the rear pinion spline numbers between 27,29, or 30. I have a leak at the pinion seal and a shop owner thinks that replacing it with a yukon yoke will fix it, the leak has persisted even with replacing just the seal. Any help would be super appreciated as im finding parts on the yukon website that say the fit my specific rear diff but then find different info online about the spline count.
Thanks
Billy

 

I'm pretty sure if factory "open" in the rear, that the 1st and 2nd both have a 27-spline (not the 30 mentioned above) 8.4"

 

Early second gen can be found with both 27 & 29 spline pinion. First gen are 27 spline and can be upgraded to 29. The few second gen I service are 29 spline pinion but who’s to say the PO blew a third and put in one from a first gen as the third member are interchangeable 8” first gen elock for 8” second gen elock and the 8.4” has the same concept. Haven’t service a Tacoma with a 30 spline pinion.

Easiest way to find out is drop the driveshaft, remove the pinion nut, pull off the flange, and count the pinion spine.

 

Hmm true I think everything is still stock oem parts though, as of previous owners knowledge. Kinda sucks bc I read so many things pointed me to a 30 spline on 2nd gens with the open so i ordered a 30 spline from yukon described for toyota tacomas 2004+ , wouldnt it be 2005+ not sure and kinda salty lol still cant figure out what I have, gonna probably drop the shaft tmmr

 

https://www.extremeterrain.com/yuko...J8DuBzafx2KbFVZPTLxoC-qoQAvD_BwE&gclsrc=aw.ds

 

sorry man, dont wanna blow up your inbox. This is the part I ordered, found multiple sources showing it fit my truck part number YY T34030 https://www.extremeterrain.com/yukon-gear-tacoma-differential-end-yoke-yy-t34030.html

 

If they’re saying 30 spline fit your year and if it’s correct, I learned something new because the early second gen I service are 29 spline.

Once you receive it and if it’s correct, come back and update this thread.

 

So on my 2004 Toyota Tacoma regular cab 2.7L 4x4 automatic base model open diff is a 8.4" rear diff ? If It measures 8" I wonder why they call it 8.4" ? I looked in my door jàm and got them 3 letters and I look it up and it says it has a 8" ring gear and 4:10 gear. So do I still get the 8.4" locker ? It's my daily driver or I would start tearin it apart and I would like to do it one time lol ....

 

As stated previously, first head tracing has two rear diff option: 8” elock or 8.4” opened, both containing an 8” ring gear. The designed is respectfully different between the two, with many claiming the 8.4” being more robust. With that in mind, yes, you’ll need the 8.4” locker.

I have no association with ECGS but you’re better off buying your third/clamshell through them and sending your core in afterwards. This saves downtime and comes with a warranty.

https://eastcoastgearsupply.com/c-1065064-assembled-3rds-clamshells-96-04-tacoma.html