Trying to help a friend diagnose a problem that no mechanic can solve. I dont have the truck, just relaying what I know.
The TLDR version
2010 Tacoma DC TRD purchased new original owner
Dial shift on the dash, ADD front axle with motorized Tcase
100% completely bone stock top to bottom
7 broken CVs, 0 during the first 4 years, now twice a year
Always after disengaging from 4 HI
Always the driver side shaft and when the wheels are turned.
This truck is used in 4X4 weekly in mild offroad use field farm roads etc. It is not wheeled by our standards. After replacing the shaft is is driven and shifted in and out of 4X4 dozens of times with no issue then suddenly boom a broken shaft. No issues or road noise before breaking.
Whats causing it? The ADD actuator not working properly? The Tcase not shifting properly? Broken spider gears?
The detailed discussion
http://www.pirate4x4.com/forum/toyota-t ... hafts.html
2010 Tacoma Breaking CVs
Moderator: Club Officers
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FJCcrawler
- Posts: 505
- Joined: Fri Aug 30, 2013 7:18 pm
Re: 2010 Tacoma Breaking CVs
I feel like it'd be wrong if I didn't chime in given I'm on luck number 13. 
Details on where exactly it's breaking, I.e. Splines, outer splines, at the Cv joint?
Think I might know what's going on, had this happen once before when the 4Runner was completely stock. Happened in a grocery parking lot. Ended up being fucked up broken spider gears locking the diff(in a bad way) causing a weird bind. Since the driver side is connected directly to the diff w/o a disconnect when there's a bind between the diff and shaft, somethings gotta give.
Tearing apart the ifs clamshells are a bitch and a half. I'd drain it and investigate it from there. Worse, case just pull it and split the case, shouldn't affect BL, preload or and other setting as long as the pinion but isn't removed and the shims on both sides remain the same.
If also check to make sure the ADD is functioning properly I.e. shift fork and motor moving properly and axle shaft collar engaging as it should.
Hope that gives an idea of what it could be.
Details on where exactly it's breaking, I.e. Splines, outer splines, at the Cv joint?
Think I might know what's going on, had this happen once before when the 4Runner was completely stock. Happened in a grocery parking lot. Ended up being fucked up broken spider gears locking the diff(in a bad way) causing a weird bind. Since the driver side is connected directly to the diff w/o a disconnect when there's a bind between the diff and shaft, somethings gotta give.
Tearing apart the ifs clamshells are a bitch and a half. I'd drain it and investigate it from there. Worse, case just pull it and split the case, shouldn't affect BL, preload or and other setting as long as the pinion but isn't removed and the shims on both sides remain the same.
If also check to make sure the ADD is functioning properly I.e. shift fork and motor moving properly and axle shaft collar engaging as it should.
Hope that gives an idea of what it could be.
'01 4Runner -New lower ball joints
'85 4Runner
'04 GX470
’88 Xtra cab
’94 Land Cruiser
Chris
'85 4Runner
'04 GX470
’88 Xtra cab
’94 Land Cruiser
Chris
Re: 2010 Tacoma Breaking CVs
It's breaking at the joint when the wheels are turned.
I can't imagine if it were in the spider gears that it wouldn't be noticeable at some other time when driving it? This truck is used in 4x4 more than any street vehicle I know. I am trying to convince him to just swap an entire junkyard diff assembly in since he is paying a shop. I figure that's probably cheaper in the end.
When I left work he was on the phone with toyota trying to,get something out of them since this has been an on going problem.
Wish I could have it for a weekend.
I can't imagine if it were in the spider gears that it wouldn't be noticeable at some other time when driving it? This truck is used in 4x4 more than any street vehicle I know. I am trying to convince him to just swap an entire junkyard diff assembly in since he is paying a shop. I figure that's probably cheaper in the end.
When I left work he was on the phone with toyota trying to,get something out of them since this has been an on going problem.
Wish I could have it for a weekend.
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FJCcrawler
- Posts: 505
- Joined: Fri Aug 30, 2013 7:18 pm
Re: 2010 Tacoma Breaking CVs
Swapping in a JY diff would be a good start. Keep me updated, this has me intrigued.
'01 4Runner -New lower ball joints
'85 4Runner
'04 GX470
’88 Xtra cab
’94 Land Cruiser
Chris
'85 4Runner
'04 GX470
’88 Xtra cab
’94 Land Cruiser
Chris
Re: 2010 Tacoma Breaking CVs
It's definitely got me curious. Its the specific circumstances.
Bone stocks truck.
Always after disengaging 4x4
Always when the wheels are turned.
Always the driver side.
But only 1 in a 100 times.
When your spider gears broke did you have many small pieces of metal in the diff?
Every diff failure I have seen had at least a noticeable piece of metal in the oil.
My first suggestion is to have the oil drained and inspected, I don't think it has ever been changed. If there is a failure in the gears it should be seen in the oil.
Will keep you informed of what I find out. If the diff is replaced I am going to ask for the old one.
Bone stocks truck.
Always after disengaging 4x4
Always when the wheels are turned.
Always the driver side.
But only 1 in a 100 times.
When your spider gears broke did you have many small pieces of metal in the diff?
Every diff failure I have seen had at least a noticeable piece of metal in the oil.
My first suggestion is to have the oil drained and inspected, I don't think it has ever been changed. If there is a failure in the gears it should be seen in the oil.
Will keep you informed of what I find out. If the diff is replaced I am going to ask for the old one.
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FJCcrawler
- Posts: 505
- Joined: Fri Aug 30, 2013 7:18 pm
Re: 2010 Tacoma Breaking CVs
There's always been pieces of metal in the diff in every failed diff I've seen. Oh yeah there was definitely a sign of failure when my spider gears broke.
'01 4Runner -New lower ball joints
'85 4Runner
'04 GX470
’88 Xtra cab
’94 Land Cruiser
Chris
'85 4Runner
'04 GX470
’88 Xtra cab
’94 Land Cruiser
Chris
Re: 2010 Tacoma Breaking CVs
Update
The mechanic that has it went to put a shaft in it and the owner was just going to sell it an give up. When they pulled the shaft they found thin shims between the shaft and housing. They tried to put in a new generic brand shaft and it was a sloppy fit. Not sure how they resolved it but they got it back together and the owner is driving it trying to decide whether to find a better mechanic and diagnose and fix the problem or just trade it for a new truck.
The mechanic that has it went to put a shaft in it and the owner was just going to sell it an give up. When they pulled the shaft they found thin shims between the shaft and housing. They tried to put in a new generic brand shaft and it was a sloppy fit. Not sure how they resolved it but they got it back together and the owner is driving it trying to decide whether to find a better mechanic and diagnose and fix the problem or just trade it for a new truck.
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FJCcrawler
- Posts: 505
- Joined: Fri Aug 30, 2013 7:18 pm
Re: 2010 Tacoma Breaking CVs
Interesting, I have heard that non-oem CVs dont fit well in 2nd gens, but I hardly think thats the problem with why he's blowing so many. Did they try to drain the diff, yet?
'01 4Runner -New lower ball joints
'85 4Runner
'04 GX470
’88 Xtra cab
’94 Land Cruiser
Chris
'85 4Runner
'04 GX470
’88 Xtra cab
’94 Land Cruiser
Chris
Re: 2010 Tacoma Breaking CVs
No, he is looking for a good mechanic to take it to. If I had a couple of free days I would offer, but I just dont have it right now.
Re: 2010 Tacoma Breaking CVs
The mystery continues. He took it to the dealer and had them pull the front diff apart. They found no broken parts and no abnormal wear. Rather than sink more money into it it's probably getting sold.