TRD diff in a SR

You would need the full housing. The pumpkin itself is larger and mounts to larger studs in a larger housing. The axle shafts are 32 spline vs 30 spline. The drum brakes, lines, ABS sensors, breather fitting are all the same.

The housing will bolt to the leaf springs and shocks fine. The companion flange on your diff will have a smaller 60mmx60mm pattern I believe compared to be 66mmx66mm of the larger diff. But I may be wrong on that, they might both be 66x66, there is some inconsistent info out there that makes it hard to tell for sure without just going out there and measuring.

I’m in Dallas TX and will have a 5.29 TRD OR complete axle for sale eventually (in a few months). I’m building a 2nd gen axle with a TrueTrac and 5.29s to swap into my truck because I do not use the locker. I will be selling with it a 4WD Locker ECU which will plug into a non locker 4WD truck. The wiring isn’t there but some wires could be added to the harness for the ECU and ran to the stock added locker. I bet someone here could help make it work with OEM wiring terminals that you simply add to the connectors.

 

@BLtheP didn't realize the shafts had a different spline count as well.

 

Yeah, only on the 3rd gen 8.75. The 2nd gen 8.0 e-lock, 8.0 non-lock (“8.4”), and 3rd gen 8.0 are all the same shaft part number left or right which is 30 spline. All shafts use the same wheel bearings. Of course 2nd gen 5 luggers are a different shaft, I don’t have one of those so I don’t know the ins and outs of them but I’ve done a lot of studying between the 6 lug 2nd and 3rd gen axles.

 

pm me. i have a few things that are needed to use the 3rd gen e locker. i ended up buying the premade locker anytime module so ended up not needing.

 

Price out a truetrac module and install. Probably cheaper upfront. Pair it with a regear to save even more money.

Or you can go junkyard hunting and pull a whole axle if that's what you want.

 

What tires are you using?

 

Just for Interchange information

Any truck with a factory E-locker, or manual transmission will have the larger 8.8" rear differential. This is regardless of engine.

All others are 8.0" rear differentials.

In V6 trucks the autos are 3.90 gears.
Manuals are 4.30 gears.

In 4cyl trucks the autos have 4.30 gears whole the manuals are 3.90.

Now, I have a TRD Sport with a manual and have been piecing out the parts to try and do this conversion. With all my parts almost collected, it would have been smarter to find a complete diff at a wrecker to swap. And may be the way I end up going despite the parts I already have.


The wiring part seems easy enough. @BigWhiteTRD provided a diagram here https://www.tacomaworld.com/threads/2017-e-locker.585669/#post-19521592 . That whole thread has some great info.

 

I've been doing some testing lately as I am going to delete the locker in my truck like I mentioned earlier. I did some searching and learned a bit about the different 4WD control ECUs over the years. The following part numbers and descriptions apply to 3rd gens:

89533-04030 - 16-19 w/o off-road, 4WD
89533-04041 - 16-19 with off-road, 4WD
89533-04050 - 16-17 with off-road, 2WD
89533-04051 - 18-19 with off-road, 2WD
89533-04060 - 20-23 w/o off-road, 4WD
89533-04070 - 20-23 with off-road, 4WD
89533-04080 - 20-23 with off-road, 2WD

I have a 2021 OR 4WD, so I have the 04070 part number. For testing, I bought an 04060 off of eBay and swapped it in. Everything in my truck still functions 100% perfectly, including A-TRAC, the only thing that does NOT function is the locker, which is the difference between 04060 and 04070. The locker switch does absolutely nothing now if I press it.

I share this to suggest that buying the year specific ECU and adding the locker wiring to the connectors and then running it to the diff might be easier than doing the diode and resistor and it might even end up illuminating the locker indicator on the combination meter, potentially keeping things "stock".

What switch is used to tell the ECU to activate the locker is up to the owner, but this (buying the ECU and adding the few wires) might be an easier way to make it happen. Obviously since you have a 2017, you'd want the 04041 ECU, and you should have 04030 currently.

 

Excellent information. I have though that this maybe possible. I don't know if my instrument cluster had a locker lamp though. There isn't one that illuminates when the system check runs at key on. I may have to swap the cluster.


I took a screen shot of that info, thank you

 

There is no locker illumination at startup. I went back and checked a video I had taken with the locker and stock locker ECU in place. No illumination of locker at startup.

My guess is that installing the locker ECU and hooking up the locker to it appropriately will light the dash as it’s supposed to and will control the locker appropriately. But I have no way to confirm the illumination part, that will ultimately be found out by experimenting.

 

Looking at the electrical diagram, diff locker swith provides ground to pin 15 on 4wd control unit. Control wires to diff locker: Pin 1 SL+, pin 5 SL-
Basically, grounding pin 15 should activate the diff lock coil.
Transfer indicator is pin 12, other end is grounded

 

Seemed pretty simple when I looked at it.

 

chances are it does. similar to my cluster having a fog lights even though i didnt have the lights originally. would they really go through the trouble of building 2 different types of clusters for that change?

 

To be fair, there are a ton of different cluster part numbers, but I don’t know any of the differences between them. They probably all have locked illum and fog light illum though.

 

The indicator lamp is there. The lamp will go on or flash if there is a pulse on CAN network between 4wd control unit and instrumnet combination unit

 

I'm thinking the complexity starts if non-offroad control unit does not have Locker logic available and going to offroad type may compromise vehicle stability (vacuum based vs electrical buster)

 

FYI the factory locker only works in 4LO.

 

Note that in 2HI, TRAC and VSC are enabled and will cut throttle to reduce wheel spin. This behavior is not ideal in sand/mud/snow/ice. You should push the traction control button to enable AutoLSD mode or put the truck in 4HI.

Before I understood this, I got my self stuck in sand had to engage 4HI to get out.

 

It would be best to get an aftermarket locker that is made for retrofitting.

 

The best setting for mud may be shutting everything off. The AutoLSD is just version of traction control that applies the brakes to the spinning wheel to force the other wheel to spin. This brake application can still hinder forward motion.

Every situation can be different though, so understanding the settings of the truck and systems can help too.