Title sums it up, hope I can provide better context though. I have an 89 3.0 powered 4runner with 200k on the odometer and since I got it it has been shifting incredibly rough in certain gear shifts. I havent hooked up the ECT switch yet either so that is not in play at all. Mine came without one and the switch I picked up has a different plug to the one on my harness. I dont have the heart to cut up either one yet but it's important to note because it's not impacting shifting points at all. I recently just redid my timing belt and went through and refreshed my engine harness as well. Both are fresh and while I didn't test it myself I can assume my overdrive coolant temp switch is working. I also have reasons to assume this transmission has either never been serviced or just fluid changed and potentially never filter changed because quite a few other things on this car were untouched from the factory including fuel filter and other ignition items that needed replacing. It is also overfilled which may just be my issue. PO had it overfilled and said it leaked atf. It does exactly that but mainly from transfer case and not as much from transmission.

As far as the operation of the trans goes. It has a super hard time shifting from anything to reverse. it takes more than a few seconds and then slams into gear. Shakes the whole car. Can't be good for it. In drive, shifting from 1 to 2 is fine almost always, but 2 to 3 is almost always hard like the reverse shift. 3rd to 4th can do the same but less often than 2 to 3. I dont know about other shifts and if testing them helps diagnosing I can do that.

The only thing I guess I'm worried about is changing anything in a transmission that does work. Yes it's rough but it drives. People constantly talk about horror stories with auto transmissions where trying to filter change or change anything else makes problems exponentially worse. Should I just drain to appropriate levels in the transmission and assume all will be well? Im leaning towards that as I wanted to take it on a road trip in the near future. Engine runs well now that I've serviced and stays at normal temps so far so hoping for the best with the trans too. This could also be something to take straight to a transmission shop so if anyone knows one worth driving to for toyota specific service in the san fran bay area I would be willing to do that unless I'll definitely get the same results from any local reputable transmission service shop. All input is welcome here. Thanks

 

It’s extremely important to get the adjustment right on that cable!! If you don’t get it right you’ll have delayed shifting late or no overdrive engagement..if torque converter never locks up your coolant temp sensor the one the computer uses not the one for guage is bad. Rear intake between firewal and intake.




snaptube vidmate

 

Definitely grateful my coolant temp sensors seem to be working. I actually drove her for two hours straight road tripping today and it handled it beautifully. Gave me many opportunities to run through the gears and I can more accurately describe the problems I'm having. To be clear this is an A340H and I recently adjusted throttle and kickdown cable as per the fsm so those seem to operate correctly too. To be clear I have no issues downshifting. Properly adjustinbg the kickdown helped with that and all is smooth there. I am also definitely getting into overdrive, albeit later than I would like for it to be kicking in. I seem to have to be doing something like 4500 rpm in fourth for longer than I would like for it to switch to overdrive. I don't have a working ECT power/regular mode currently because I have the seemingly wrong switch for it. There must be different years and plug styles. I'd like to not chop up the one I have on the loom or the switch side so I will be waiting to use ECT power mode until then. Adjusting kickdown and throttle did nothing for my upshifts unfortunately 1-2 is still perfect and smooth. 2-3 and 3-4 are a rough explosive upshift every single time. Shifting into overdrive seems to be okay too, not perfect because the RPM its looking to. shift at is a little high for my taste but that is up to the transmission and how hard I can gas it.

 

If anyone tapped into this thread expecting results. I am making a new thread on rebuilding my A340H.

Found a very broken accumulator spring for the 2-3 accumulator. I am making a broad assumption when i say this, but my guess is that it is the source of the rough shift. Especially since it's job is to help the 2-3 shift actually happen.


For context, the following image used to be one spring, not three.