Was hoping someone here could help me out, since the shop can't seem to figure it out. CEL came on around 60K. First visit to shop: pullled code P0775 (shift solenoid B malfunction), flushed transmission fluid, replaced water pump and thermostat. Less than 10 miles later, CEL was back on again (same code). So, on second visit to the shop, they replaced the shift solenoid. Again 10 miles later, CEL was back on (same code). Also noticed in between services that it runs at high rpms (about 4500 at 70mph). When I let off the gas on the highway, the tach drops immediately to idle speed (about 800 rpm) and I can free rev the engine (as if it's in neutral). I have to bring the rpms back up over 4000 to re-engage the engine and get any power back.

More background: this just started after I lent it to a friend who says he engaged the multi-mode 4WD on the highway -- probably around 60mph.

Any ideas on what's going on?

 

I doubt engaging the 4wd would have damaged the tranny, moreso the xfer case if anything (though why was he engaging it at all? But that's neither here nor there).

I don't suppose you happened to see if the fluid was burnt before it got changed did you? Sounds to me like some major slippage in the tranny, but there could be any number of reasons for that. Just to clarify - the truck was not taken off road correct? Just highway drivin'?

 

Not sure if the trans fluid was burnt, but they said it was very dirty, which was why they didn't replace the solenoid on the first flush. Truck hasn't been off-road in about 10K miles. (Yes, sad, I know.)

Any chance this could need a trans rebuild or are we still too early in the process for that?

(As per the "friend", I wondered the same thing myself. I think he engaged the 4WD multi-mode going about 60mph on dry pavement and was probably going even faster after that. Guess he was trying to figure out how durable Toyotas really are. Of course, I'm still trying to figure out whether to send him the bill.)

 

Very dirty huh? Hmm, that's not good. I burnt out the tranny on my Tundra by getting the trans nice and hot, and going for a mudbath - the contracting air sucked mud past the pressure seal and contaminated the fluid. Instant new transmission. The heat welded the clutch plates together (great paperweight), and because of the dirt in the fluid I was told that they couldn't just rebuild the tranny as there was no way to flush 100% of it out, it would have to be replaced. That was an expensive day...

It's possible that your dirty fluid eventually caused the failure of the components in the transmission; could be from him engaging 4wd (but I really doubt it), more likely he just drove the cr@p out of it, acellerated fast, redlined, etc and it finally just gave out. That's my opinion however and I am NOT a mechanic, so take it as such.

I don't think he got the fluid dirty on his own just driving quick down the highway (unless there were particles in the fluid from the components themselves), but I guess it's possible that it was just a time bomb waiting to happen, and some abusive driving finally kicked it over the top.

 

Lets see...
Lend 'friend' truck...
Friend returns truck...
Truck shows codes and runs like crap...
Friend admits doing (1) dumb thing...maybe more?
Truck goes to shop for repair, not helping...
Truck still runs crappy and sounds like the tranny is shot?...
Cha-ching$$$$$
Friend gets the bill....and a slap in the head...just because
Good luck.
butnut

 

Just wanted to post a follow-up, in case anybody was still following this thread.

Turns out the next part they plan on replacing is the OD solenoid. I guess they're failing in order.

They didn't really have any explanation, but from the research I've done, I think the statement in this FAQ kind of sums it up (don't get me wrong though, I still love the truck and part of my surprise is that I haven't had a single other problem, not even a lightbulb failure):

From the 4Runner FAQ:

[...snip...]
F. One Person's Opinion of the Ultimate 4Runner

There aren't too many known consistent problems with these trucks. If there is a weak link, it's the transmission. The manuals have shown a tendancy to have less tolerance for abuse than the rest of the truck.
[...snip...]