740 wagon transmission concern

My Volvo 740 wagon has been shifting into 2nd and 3rd gears at a much
higher RPM (about 4500 to 5000) lately, though not all the time. As it
revs higher and higher, I can almost use the gas like a clutch and
relase it quickly to get the engine to go into the next gear. However,
I shouldn't have to do this.

Also, there are times when I remove my foot from the gas pedal as I
approach an intersection and I can sometimes feel the car grabbing
once or twice before it downshifts.

Any idea if the transmission is going? What can I do to rule out other
possibilities before taking it to a mechanic who sees big dollar signs
every time he ehars the word transmission?

Thanks for your help and advice.

Mark

 

You probably have the AW tranny (PRND21 and separate overdrive control
button). They are nearly bulletproof. Your symptoms are common with either
of two problems: the kickdown cable is not retracting smoothly or the engine
has a problem that causes you to have to depress the throttle too much to
get the power you need.

The first thing is easy enough to check (and the more likely problem). Under
the hood, at the throttle body, you will see an aluminum-looking spool with
three cables wrapped on it. Two wrap around it one way - those are the cable
from the accelerator pedal and from the cruise control vacuum motor - and
the other wraps the opposite direction. That is the kickdown cable to the
transmission. Check to see that the kickdown cable lays properly in the
groove, with no slack. Then open the throttle (engine *off*) all the way by
twisting the spool and watch the kickdown cable as you slowly release the
throttle. It should maintain tension and lay into the groove smoothly.
Repeat a couple of times to verify it works smoothly. If the cable hangs up
and becomes slack at times, graphite lubricant in the cable housing should
fix it up. I like "Lock-ease," a spray can with graphite in a kerosene
carrier that is available at hardware and auto parts stores in the lubricant
area.

If the cable is working smoothly, your problem is likely a drivability
problem in the engine. The effect is the same as the sticky cable; the cable
is pulled out farther than expected for the amount of power the engine is
generating.

Mike

 

on my 240, which I suppose is similar to your 740, there's a cable that I
understand controls the upshifting of the transmission. It runs over a large
metal pulley just above the throtle plate of the intake manifold, where the
large black air intake hose connects. When I clean the throttle body, I
usually have to reseat the cable in the groove of the pulley. Perhaps yours
has jumped out of that groove and no longer signals the transmission
properly, or the cable may be binding in the sheath.

Another thought... have you checked the transmission fluid lately? You might
be low. Or perhaps just changing the fluid would solve some of the
problems... Not difficult or expensive if you do it yourself.....

 

Sounds like your kickdown cable is binding, if that's not it, try a fluid
flush, but the cable is my first suspect. It attaches to the throttle spool.

 

I tried the spray on the kickdown cable but that hasn't changed
anything. It seemed to be moving okay anyway.

I'm taking it in for an oil change and will have them check the
transmission level too. I took the tran. dipstick out yesterday and
the fluid was dark brown.

Mark

 

My '91 740 wagon did the same thing. It rev'd higher before shifting, and
there was a real lag once it did shift. Unfortunately, there was no easy
fix. I ended up putting in a rebuilt tranny for about $1,000. The mechanic
said 740 transmissions are "known for that" although I had not heard of it.
That was about four years ago. I now have 260,000 km on the car - about 1/3
are with the rebuilt transmission.

Grant