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Discussion Starter · #1 ·
Anyone on the board know anything about Toyota's automatic Aisin brand transmissions? My 22 yr old Tundra with an A340E 4 spd auto transmission has developed an intermittent stutter when cruising in 4th/OD...with or without the cruise control on. Otherwise it still works flawlessly...for an auto slushbox with 229k miles that is.
I think it is trying to downshift to accelerate, like when you hit a grade in OD and it downshifts and then accelerates until it reaches its sweet spot and then upshifts again. It isn't over temp and otherwise shifts smoothly. I've done a fluid change, drain and refill, but I've heard power flushing is bad juju for high-mileage auto trannies.
The stuttering is intermittent and brief, like a second or two at most, and its not slipping...just stuttering.
Thanks in advance for opinions/ideas/past experiences that you can share.
 

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So it's like it's trying to shift but doesn't quite do it? My brother had a bad switch do that. His truck had a button on the column shifter to lock it out of OD on secondary roads so it wouldn't be shifting up and down constantly. The switch went bad and kept kicking in and out. My 2000 F150 has that switch too. Not saying that's your problem but the electricals can be a real PITA.
 

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Discussion Starter · #4 ·
When it stutters its just momentary...runs through all the gears correctly though, and doesn't always do it. Gonna do a 2nd drain and refill today to complete a full fluid change and add some Lucas snake juice to see if it clears up. Everything I've read points to bad torque converter so may be looking at a rebuild or remaufactured tranny replacement. Love the truck otherwise but it is 22 years old with 229K on the clock so who knows.
 

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Sounds a lot like the judder the old 700r4 gm trannys had. I'm guessing that it goes away if you pull it out of od down into 3rd (direct drive)? If memory serves, your thoughts match what the repair was on those.
 

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Discussion Starter · #6 ·
If a fluid change and additive doesn't cure it, I'll probably price a remanufactured slush box from an 01-04 which has stronger innards. The price for that beats the mrkt price for another used truck of unknown origin & service history.
 

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Discussion Starter · #7 ·
Well after a drain & refill & a half bottle of Lucas genuine serpent whizz it is behaving better...smooth shifting thru all gears, OD on and off, and no stuttering ascending a grade. The fluid I drained out was kinda purply looking...so maybe the Sea Foam trans tune did some good while it was in there...wasn't particularly foul looking/feeling either. I still have enough fresh juice to do another drain/fill...each one of those only gets about half of the fill capacity.
 

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Good fer you Tmac.. (y)

Sounds a lot like the judder the old 700r4 gm trannys had. I'm guessing that it goes away if you pull it out of od down into 3rd (direct drive)? If memory serves, your thoughts match what the repair was on those.
 

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I’m leaning towards torque converter, but I’m no expert. I have an ‘02 with 260k. If you’re not a member already, get on Facebook and join the “First Gen Tundras” group. A great, helpful, knowledgeable group. It offers tons of experience and information on these everlasting trucks.
 

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My 2012 Traverse does some stuttering as well, I wonder if a fluid change and perhaps an additive would help…
 
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