UK Car Repair Questions? Ask a Mechanic for Answers ASAP
Hello and welcome to just answer and allowing me to assist you. sorry to hear of your problem but together we may be able to solve this.T o start may I ask a few questions to get a better picture of what I'm dealing with. have you changed the gearbox oil recently and differential oil as well? Is there any noise accompanying the noise? Do you have a tachometer in the vehicle?
Thanx for the info. that's good you have a tach it will be useful to do this test. What I want you to do is run the car till warm then try to take off in high gear giving it a bit of throttle and watch the tachometer to see if it rises faster then your speed tell me what you feel and see.
lets do it this way. find a road with very little to no traffic and start off to about 15 -20 miles and hour then shift to 5th or 6th gear and floor the throttle just for a brief moment , enough to see if the RPM'S go up fast as the vehicle seems to not increase in speed . this will tell us if what I suspect a clutch problem.
just reviewing your notes when you said when it happens you down shift from 6th to 5th but at same speed and it goes away tends to tell me it is in the gear box, not only did you change transmission speed when you down shifted but you also eliminated the engine by depressing the clutch so you sort of narrowed it down to everything in between that's the transmission in particular related to 6th gear. One other thing I would like you to do. change the transmission and differential gear oil and see if any particles come out with the oid oil and get back to me.
I can't see how an ECU could cause that, what did they say how they determined that?
After reading that and eliminating what we did makes total sense about the ECU being faulty because it would only spit out codes if it were a input problem. it was obviously rpm related . I have not personally run into that particular problem with our Toyota's but have had some other drive ability issues that we had to flash the ECU with new programs. in some cases replaced them. Thank you for sharing this with me ,and yes does make total sense. You can also ask the dealer if they don't have a fix from Toyota itself to look at your findings and do a flash product report. may help you repair this . that's something we do when we run into a problem on more then one vehicle but the same problem , then we would submit a complete report of the symptoms and what we found to repair the issue., then submit it to Toyota. In this case that's what needs to be done . If you cannot get help to cover the costs right now I would recommend trying to get one from the wreckers , don't go aftermarket or rebuilds you would end up with other problems. Yes go for an ECU definatly. good job on research and sharing . cheers ***** ***** luck.
as long as you stay out of 6th gear to aggravate it should be ok, this is one vehicle I personally would like to see on a scanner , that would show me exactly where the issue is by watching all perimeters because there are too many variables that can cause this and can be time and money consuming. You see putting it into that gear and only at 2000 rpm puts a load on it and acts like your taking off in high gear from a stop. it's just too much for the engine and it bucks or vibrates. with all this I retract my previous statement of transmission problems and would be surprised if it isn't engine related timing or fuel related . good luck and keep me posted.