So I'm dealing with this rpm wiggle while dipping my toe into the throttle at cruising speeds. The scan tools shows my lockup solenoid coming on and off when the tach starts to wiggle. It only happens when trying to accelerate while at cruising speeds. I have changed the filter and fluid as well as adjusted my trans throttle cable. I know the computer takes inputs on tps, trans temp and speed to allow lockup. I'm going to test and adjust tps next. I repaired some wiring but nothing has changed. Anyone have experience with this? 96 LX450 with the A343F transmission. It seems I cannot upload a video from my phone of the tachometer :/
A343 trans rpm wiggle under light acceleration (1 Viewer)
- Thread starter AndoFZJ
- Start date
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ppc
M Go Blue
Based upon what you have described so far, the operation sounds normal.
Post a video to YouTube and then provide a link here.
Use more precise and descriptive language as "wiggle" doesn't indicate the exact RPM change. A better description is "RPM changes by approximately 400 RPM".
Also it is important to provide information as to:
Previous vehicle history, new owner, how long this problem has been occurring etc.
Recent repairs, additions
What size tires?
Post a video to YouTube and then provide a link here.
Use more precise and descriptive language as "wiggle" doesn't indicate the exact RPM change. A better description is "RPM changes by approximately 400 RPM".
Also it is important to provide information as to:
Previous vehicle history, new owner, how long this problem has been occurring etc.
Recent repairs, additions
What size tires?
- Thread starter
- #4
Sorry, I was kinda in a panic when posting. The tach moves about 100-150 rpms back and forth in about .5 to 1 sec intervals. I will try to post a video later. The truck had a rough life before me. I sold my built 85 4runner and bought it for the same price. I got it with 105k on it but it was never maintained properly. It has 160K on it now and the issue has popped up with in the last month. The transmission throttle linkage was mixed up with the crusie control by the PO. It had the windsheild leak so I traced down a lot of corrosion. I got the climate control and all the bells and whistles functiong as they should. I have gone thru pretty much everything on the truck. Rebuilt the front end, bg trans flush and filter replacment, ome 3 inch lift and shocks, 285/75/16 Duratrax, rebuilt the lockers, headgasket job, valve stem seals, radiator, tstat, cap, rotor, wires, plugs. I did forget to reinstall the magnets during the trans service around 30k miles ago. :/ Althoug, I did install a strong magnet on the outside of the pan. I recently replaced the filter and fluid again but reinstalled the magnets, the fluid and pan didn't show any concerns. The truck needs a rear driveshaft, the splines on the yolk have excessive play. The birf on the right side is starting to click on heavy accel. while turning. No codes in any system, runs fine besides a slight lumpy idle that I deemed to be normal. I'm an auto tech by day for BMWs and other euro vehicles. This is my winter vehicle that I built to drive 12 hours into the middle of nowhere in Michigan's Upper Pennisula so I'm real ocd about it lol Thank you for the reply!
- Thread starter
- #6
Well just the tachometer flipping at the one point is similar, just in the manner I described above. It will downshift out of overdrive but then the tach will move back and forth about (100 rpms) while giving a constant light accel, not stay in fourth.
If the converter is unlocking when dipping into the throttle a slight rise in rpm is completely normal.
- Thread starter
- #8
I do have a whistle under accel around the same speeds that I have the issue with the tach. Haven't listened on the hoist yet to see if it's in the trans but I assumed the bad driveshaft could cause sounds. I need to readjust the tps, just realized I was shimming the wrong throttle stop while adjusting and testing. :/
- Thread starter
- #9
The rise would be normal but it rises and falls, back and forth up to 4 or 5 times depending if I stay on the same throttle location or not. The scan tool reading of the lockup solenoid turning on and off would corrilate with the flicker of the tach.
Malleus
Far west of Siegen
I just posted the A343F transmission FSM - troubleshooting section, in the Resources section, 80 series
HTH
HTH
ppc
M Go Blue
From your video and further description, definitely not normal of course. In the video it looks like overdrive is enabled, engine temp shows normal but have you driven a sufficient distance to also warm up the transmission? Does the same problem occur when overdrive is disabled?
Malleus
Far west of Siegen
Please check the troubleshooting section, ppg AT-34 thru AT-40 and let us know if you have any trouble codes. The code values are on ppg AT-42 thru AT-45. LMK if you need any of the sections covering those codes (if any show up).
- Thread starter
- #14
Thank you so much! I have the old school Toyota scan tool and will hook up, trigger check mode and go for a cruise! Hopefully a code pops up!
Dave 2000
Not all Land Rovers are useless!
That is so indicative of a bad connection perhaps earth? Or perhaps the stepper motor in the tachometer is going bad, does it do that if you were in first for example and held engine at similar revolutions?
Regards
Dave
Regards
Dave
Malleus
Far west of Siegen
^this. That's why I suggested checking for A/T codes.
Malleus
Far west of Siegen
You could do that, or just check the existing codes. If it's an A/T problem, you should have a code already; if it's not, I doubt further driving will cause one to pop.
But I've been wrong before.
- Thread starter
- #18
I have checked for codes and came up with none. Perhaps the check mode will be more sensitive and pick something up? However... I left work to a doc appointment, then home and the symptom is GONE!!! The downshift is normal and stays in gear.without a flicker until I'm well over the speeds that the issue was happening. Ugh, I will still keep the scan tool ready to hook up. Maybe the tps adjustment needed time for the ecu to relearn? 
I'll keep you updated, thank you all for the help! I'll look into grounds and possibly the tachometer itself. It never happened in any other gear or situation and didn't happen with o/d off.
I'll keep you updated, thank you all for the help! I'll look into grounds and possibly the tachometer itself. It never happened in any other gear or situation and didn't happen with o/d off.
I'm not hearing any change in engine RPMs, but you're in a better position to judge that. I suspect that your tach is a lying scoundrel.
Does the Scantool show the lockup solenoid *cycling* like the tach, or does the tach dance simply start around the time that the transmission has activated or deactivated the lockup solenoid as it normally should?
I can tell you that if I drive at a steady speed (say, 50mph) and lightly tap the brake to cause the transmission to drop out of lockup, I can definitely hear the change in engine RPM.
- Thread starter
- #20
The lockup signal from the scan tool and tach movement would match. I would definitely feel it in my seat when the tach would move or "drop out" Not sure how much engine rpm would change compared to what the tach is saying. Its so little of movement that happens quick so it would be hard to hear, a lot of road noise. Now when I accel during cruising (trying to recreate the symptom) it stays locked in fourth and I don't feel anything wrong and the tach reading stays constant until I hit overdrive. Lets hope it stays that way.
