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Hi guys. Can anyone help me with this. I posted a question earlier in the year asking about my car giving a big thud or clunk when the transmission is shifted from drive to reverse or vice versa. And shifting from first gear to second gear. Third to fourth it doesnt give any problems. Earlier suggestion given was for me to change my engine mount. Ive changed all but the problem is still there. I have a front wheel drive nissan cefiro a32, 2.5ltr. Thank you.
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See if you can get a shop with maybe a drive on rack (alignment rack). Have the guy put it up in the air and have someone sitting in the drivers seat with the engine running. Shift from Drive to Reverse and back. Do a careful examine and the cause might present itself. Use care while doing this test, we do not want anyone going down for breathing exhaust fumes or having the car fly off the rack.
S-
Hi cama,
On some Auto Transmitions you have an air hose coming from the vacuume pump (possibly via a solinoid valve) and many also via a regulator into a control unit fitted to the side of the transmittion.
If you have a problem, eg a hole in the hose a faulty, regulator, solinoid, control unit, or vacuume pump.
You will get exactly the symptoms you have described.
Your problem may be rectified simply by refitting a hose that has came off.
Hope this helps
Kdr
If the OP had mentioned change in shift points–then checking the vacuum modulator valve and/or governor makes sense.
The gent with the issue didn’t mention it–but it’s a valid point. When the car shifts–are the points correct for the up shifts? Or does it seem like it’s shifting at a higher RPM then it should be–and when it does shift–Is it like a higher RPM SLAM into gear? Fast test would be to take off from a stop sign using gentle accel. Do the points seem like the engine RPM Is reasonable….or does the RPM seem to go very high….shift harsh…etc..
Just wondering……
S-
The modulator is the correct term, I called it a ‘control unit’ at the time I posted I couldn’t for the life of me remember what it was called. To save any confusion.
Still I stand by the post, and agree with the addition added by S.
Kdr
It could be a vacuum modulator issue as suggested. However if the vehicle is newer and does not use a vacuum modulator then it could be an electronic issue or an issue with the transmission itself. More info on solving transmission problems here.
http://www.ericthecarguy.com/faq/solving-transmission-problems
Keep us posted on your progress.
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