2002 Tacoma Prerunner double cab. 3.4L.
Automatic transmission. B03A differential. No locker, no abs.
580,000 miles.
Beginning to get some low rumbling noise and vibration. Found a rear end from a 2004 Tacoma but they are telling me that it has a B03B differential.
If I swap out the complete rear end of the B03A original will I:
1. Need to make any modifications?
2. Will it negatively affect my mileage?

Have not been able to verify any differential specs by VIN number. Waiting on a return toyota call.
​​​2004 VIN 5TENM92N24Z426429

 

Parks Toyota of Deland was unable to tell me anything from the VIN.

 

On your VIN there is a line item that says A/TM: B03A B=8" ring gear, 03=4:10 ratio, A=2 pinion gears, and a 4 would be 4 pinion gears. They look compatible in the same housing to me, but I don't work at toyota lol, and isn't the prerunner 2WD, so as long as it fits it should work. Google search OEM gear ratio chart, there is always the chance your VIN doesn't rep whats in the diff if its been swapped.. Usually its the rubber in the slip yoke on the 2wd taco's that wear out causing rumbles.

 

I've never heard of the slip yoke going bad but after a quick search it could quite possibly be the culprit. Thanks for that bit of knowledge.
What I am trying to find out is if anyone has replaced a complete B03A rear end without ABS/without E Locker with a complete B03B with ABS/rear end.
1. If so, did any modifications have to be made outside of blocking the the ABS ports?
2. Did it negatively affect their mileage?
Being that the replacement differential is a four pinion rather than the two pinion, I don't anticipate that the B03B would fit in the B03A housing.
This has been my daily driver for over twenty years and usually do 100 miles round trip to and from the areas that I work at. So fuel mileage is a deciding factor for me and a quick swap is what I'm aiming for.
I understand that the four pinion (B03B) is stronger, more durable than the two pinion (B03A). That would be a plus since I'm doing my best to get another 580,000 miles.

 

You could do that since yours is non-abs I assume by the question, non-abs would be reading the speedo from the transmission tail to driveshaft, you couldn't go the other way as ABS is required for speedo if your vehicle came equipped with ABS, Personally I'd keep it non-abs, makes rear axle bearings twice as easy and cheaper having less parts to Re&Re. Yes very common issue to have the rubber inside the 2wd slip yoke fail and cause vibes, very common, make sure you order a shaft that matches the cab size of the truck as they are all different lengths obv, I guess you could order just a slip yoke and u-joints.

EDIT again: if you have a non-abs 2wd locking rear diff and housing, and you've replaced rear wheel bearing properly(inspecting axle shafts), and the slip yoke and shaft checks out ok and then find you still have issues, then I wold Call East Coast Gear Supply ECGS and have them put together a 3rd member for you, its not a bad job, done that a few times.

 

I did find this if that is what you're referring to.
Toyota 37302-35050 Universal Joint Sleeve Yoke Sub-Assembly $191.50
How do you determine if the sleeved yoke assembly is going bad? There doesn't seem as though there is any play in it.
The center support bearing has been replaced in case anyone considers that the cause.
Trying to identify the cause without just throwing money at it.

Going to look at the assembly closer since I never considered that the interior of the sleeved yoke wasn't metal.
I will report back good, bad or ugly.

 

Ok, there is a difference between slip yoke vs slip joint, if I understand 2WD correctly you have a slip yoke that slides onto the rear tail of the transmission like in the 1st pic of the link below I realize its 2nd gen but should be similar to this #37302-24010 it has rubber inside of it that wears out.. A slip joint is on the rear of the drive shaft for the 4x4 like the part # 37302-35050 and allows the driveshaft to slide together and has fixed yokes at the transmission and 3rd member., I could be wrong as I'm not well versed in 2wd prerunners more 4runners so please provide a picture of your driveshaft, but even the 2wd 4runner had a slip yoke at the transmission, unlike 4x4 that have a slip joint built into the rear prop shaft.

https://www.tacomaworld.com/threads/...eshaft.729413/

 

Rear 3rd member and sleeve/yoke side

3rd member to center support bearing

3rd member and sleeve/yoke bottom

 

The slip yoke at the transmission tail, not the slip joint at the 3rd member in the driveshaft, the slip yoke at the transmission of the 2WD has rubber in it, it is an issue, unless you have a fixed bolt on yoke at the transmission, but my understanding is the Prerunner has a slip yoke at the transmission..

EDIT: and it looks like your U-joints are out of Phase, so when the Driveshaft slip joint was separated they didn't line up the splines and u-joints, the u-joints should be aligned perfectly like in the generic photo included, that alone would cause a vibration for sure, I'm surprised they used a double cardan joint and a carrier, must be a double cab thing, the 4runner 2WD has a solid shaft with just a slip yoke at the transmission, but isn't as long at double cab Taco

 

Yes, I noticed the misalignment while under there, as well. Yoke slipped out on removal for center support bearing. That will be remedied shortly. The vibration didn't worsen nor improve despite that.
As for there being a slip yoke at the front, negative.

Front drive shaft side

Front drive shaft beneath

 

Very interesting they used a 4x4 driveshaft and fixed yokes on a 2wd Double cab pre-runner, so no slip yoke at the trans for you got it., I don't see a rear e-locker, so non-abs, no e-locker, 4:10, learn something new everyday. Unfortunately these vibs can be difficult to trace down, a camera on that carrier bearing or other joints to see if its moving would help, other wise swap driveshafts, re&re rear wheel bearings and inspect axles, then determine if you wanna call ECGS for a new 3rd member, if you want an e-locker, you will want to hunt down a non-abs complete axle and housing ideally, you can use the ABS rear axle housing and just leave the sensor installed to plug the hole, there are kits for e-locker add-ons for toyotas. You should be able to fit any 4x4 or 2wd rear axle 1995.5-2004, most of the Taco 4x4's will be 4:10 or 4:30

EDIT: does that 4 bolt flange slip out of the 2wd transmission out of curiosity or is it fixed with a staked 24mm nut?, just curious if it has that slip yoke like the 2wd but a 4-bolt flange..?

 

The front yoke is staked.
No plans for an E Locker. I think my next move will to replace the U-Joints even though they all felt fine. They are original so they may have just reached their limit.
The slip sleeve has no movement. None of the wheel bearings felt like there were any problems. No leaks. I'll keep searching for a B03A unless it becomes necessary to swap to the entire B03B rear end. $400 isn't bad for a 112K Toyota rear end.
I do appreciate your help, thank you.
I will reach out to the company that you suggested when or if that time comes.
This reminds me of when I was chasing a coolant leak on it's 3.4L. Couldn't figure out where the coolant was going until I noticed coolant pooling in the center valley. Ended up being the bypass tube under the top center of the motor. Luckily, I'm already bald and grey.
I promise to update once the culprit is found.