rvmeush

I was wondering about the vibration problem that some people, including me, seem to experience when cruising at 55-60 mph with the engine running at about 1500 rpm. Is this problem something which can be reprogrammed by Acura to correct? It seems like enough people have reported it that it should be on the list of things to be work on. The thing I'm wondering is exactly what's causing the problem and how can it be fixed. I would hope that a whole new transmission design isn't necessary. In the best case, some sort of reprogramming of the transmission (if that's possible) would cure the problem. Any thoughts on this?

Ken1997TL

No it can't be reprogrammed. The gear ratios are fixed. You'd need different gears or at least a different final drive.

The vibration problem in the MDX's case is due to the exhaust. Basically I wonder if THAT is the problem in the TL, I haven't been in a TL that had the issue though, so I'm not much help on that point.

Ron A

All they need to do is to reprogram the rpm's. My 96TL ran 2250rpm at 60mph. If they ran the 04TL at 2000rpm at 60 mph it would eliminate most or all of the problem, IMO. If I go to SS and downshift to 4th gear, the revs go up to 2200 and the vibration goes away.

Ken1997TL

It revs that high because our 1st generation TL's don't have that really tall 5th gear.

You can't reprogram gear ratios unfortunately. They need to change the natural harmonics of SOMETHING in the drivetrain or exhaust and then you can enjoy 30+ mpg and vibration-free.

Ron A

Right you are, ken. Don't know how I came to that obviously erroneous conclusion, since if the engine revs more the car will simply go faster. I would edit my previous post but then your answer wouldn't make sense, so I will simply say I goofed.

Ken1997TL

Its all good.

Hybrid

Reprogramming the electronics COULD do it. It has nothing to do with changing gear ratios. Instead of the transmission being programmed to drop into 5th gear, at light throttle, at 50 mph (or whatever), it could be programmed to drop in a few mph higher. That way, you'd still be in 4th gear in the low 50 mph range, and by the time it shifts to 5th, the engine would be turning fast enough to ease the vibration a little.

It's essentially the same as a manual transmission driver upshifting just a little later (higher speed) as he accelerates, to avoid lugging the engine. The transmission and differential are geared the same either way. Or, the 5AT trans could do it with the sportshift.

Actually, I've never thought the vibration was anything to even complain about. It's a tradeoff for better mileage. If the trans was reprogrammed from the factory, the EPA mpg number just might drop a little, which isn't a good thing for Acura.

Ken1997TL

Yeah that could be done. I think it drops to 5th too early as it is. It really should be a gear used past say 65 mph or so. That WOULD affect EPA mpg estimates of course. I think that is why Acura does that.

Ron A

Got my windows tinted today, and driving home watched the tach as the speed increased.

In 5th gear, the tach was turning 1500 at 45 (I checked the gear by going into SS), at 50, the tach was turning 1500, at 55 the tach was turning 1500, and at 60 it looked like it was all the way up to 1600. Doesn't sound right, but that is what it read. Try it for yourself, and slowly accelerate from 45 on up, and watch the tach, which won't move at all until 60, and then only a little bit.

Can someone explain this to me. because I can't understand how the tach can stay the same unless the transmission can vary the vanes on the torque converter or something like that.

RetAF

RonA-Could be the torque converter lockup speed. Works sorta like a turbine until it locks, and allows slippage between engine and tranny.

Bitium

Only if honda does it at the factory. We can't reprogram the PCM or make changes in any form.