Transfer case stuck in neutral

Great write-up & diagnostic work, thanks for sharing. 19 out of 20 dealers or mechanics woudl've probably just said, "Needs a new transfer case. Have a nice day."

Surprised that the Tacoma's electronic 4WD shifting system even attempts to execute a 4LO shift while the vehicle is still in motion. You'd think that the ECU could use the ABS wheel-speed sensors to see that the wheels are still moving & delay that 4LO actuation attempt until they are completely at rest? Truck locks out shifting into 4HI above 62 mph -- why not lock out 4LO until 0 mph is registered for at least a full second?

 

So will you continue to run the used transfer case or swap this "fixed" one back in. Great workup and pictures really help..

 

Thanks for the update.
Good work on figuring it out

 

Hell yeah dude! Getting at the bottom of the barrel. This sounds like it’s the issue. Keep us posted.

 

The dealer did say "needs a new transfer case"....in the dealer's defense it would be more economical just to replace this unit than to pay a dealer to try and figure out what went wrong. I bought a used tcase from a wrecker for about CAD$400 and put that in. Dealer quoted me CAD$1,000 for a used case plus labour. Given I have owned this truck since new, I didn't want to just toss the tcase out - opening it up also presented a learning opportunity.

I am pretty sure there is a speed limitation set up in the software to shift from 4H to 4L...something like 3 km/hr. I was going very slow when I shifted to 4L, but I wasn't stopped. I won't make that mistake again.

 

No sure yet....fingers crossed just replacing the cracked hub fixes the issues. I most likely will leave the one in the truck in the truck and keep the repaired one as a spare. I also have a used FJ case that I picked up....just need to get up the courage to cut a hole in the floor and cut the shift console up.

 

You mentioned you changed the TCASE lube every 2 years? What did it look like? I changed mine at less than a year when I did all the drivetrain and it looked so clean I wondered if it was even worth it. I did add a magnetic drain as added protection but I didnt see any evidence of metal particles in the lube.

 

You won't be sorry when you swap in the FJ Case... I PROMISE!

 

At 2 years the oil still looked good. I think the suggested change interval is 30k miles for the tcase oil and I drive less than 30k miles in 2 years, so I suspect I could leave it longer.

EDIT. I drive ~25K miles in 2 years, so I am a bit on the early side of the recommended change interval.

 

Wow. Certainly never seen this before. Kudos to you for the patience troubleshooting and tearing down the tcase to find the problem, and thanks for sharing.

 

Awesome to see you back on the road and a great post with follow up. Thank you! My truck beeps and will refuse to shift to 4L unless the transmission is in "N" as per normal. I have never tried it (in either direction to/from 4L at anything other than a dead-stop.) Interested to know if the hidden fatal flaw is the movement when attempting this shift, no matter how slow the speed or it's direction. It's good thing to know considering the possible expensive damages or "strandedgees".

I experienced one of these "glitches" when I screwed up and shut the truck off (far from home) while it was in the process making a shift back from 4L to 4H. This is a big "No-No" as I have since learned. It makes the ECU in charge of this to get into a little snit. When I started it up again, I initially got the beeps, but no effort into shift back into 4H. After a shift to Park and another attempt from Neutral, it returned to 4H with a good "warning clunk". Tip: Don't turn the key to "off" during a 4H to 2H shift either (or vice versa). It gives the 4x4 ecu fits: as documented here elsewhere, worst case scenario is you're taking stuff apart to fix it... or paying those guys in: "National Lampoon's Vacation" to fix it for you.

Lesson learned here: Don't ever turn off the truck when the ECU is in the process of making a mode-change.

I have never again "exercised/tested" a shift into or out of 4L anywhere: running, shut off, or anything else other than in my driveway.

 

Great work OP!

 

I purchased a new hub and had to press it on with the hydraulic press. Bench tested the actuator worked fine moving in and out of 4L. Put the tcase back together and now sitting in the garage as a spare.


What I found interesting was that new hub (top part in image below) had more of a radius in the corner than the old one that cracked (bottom one in picture below with white paint). Radius in corners like this help reduce stress concentrations, that lead to cracking....

 

Thanks for posting this story and circling back to give us the RFO.

Just to document: Per owners manual for my 2014: Manual transmission: Less than 2mph for a shift into or out of 4L: >>Less than 2 mph<<. Margin-of-error there: Lets face it: pretty much/close to essentially: "0". Considering the risk of the damage in the scenario outlined here, I would never to it. (specs for an automatic are: Neutral/foot on brake and hold/shift.)

 

Awesome thread. Thanks for coming back and updating us with pics along the way

Interesting note about the radius. My money would be on that as the root of the failure. I have always 'rolled' into and out of 4Lo, anything under 2 mph has been fair game. Ive found being at a dead stop doesn't always let the gears mesh. At which point have to drop it into gear to move everything, leading to a loud bang as it finally meshes.

Definitely will have to remember to slow it down a little in future 4Hi <-> 4Lo shifts though just out of caution

 

Wanted to also add an extra thank you for providing those great, clear pictures of the transfer-case internals: something us "shade-tree" guys rarely get to see. They really shout: "Old School" which is a positive to me. The chain is especially impressive. A real treat. The pics of the cracked hub-sleeve made my eyes hurt.

 

Thanks for the update (again).
Always good to know and see what parts have been updated.

Thanks again!

 

Very interesting issue, thanks for sharing.
I linked this thread in my 4wd help thread.

The 4wd ECU will not allow a shift into or out of 4L above 2 MPH with the trans in neutral (A/T) or clutch depressed (M/T) so I doubt it was caused by shifting over the recommended speed, looks more like a defective casting.