I poured a can of fuel system cleaner in my tank.
Took the 4 $ valvoline stuff.
First the rough idle went smooth.
Then I noticed that the shifting from N to D or
R to D or D to R became much smoother too.

But I wonder if the rough shifting R-D has
already caused some damage.
Would that be the universal joints?

Sorry, I didn't see your earlier post, but what is happening when your shifting is rough?

The last time I used fuel system cleaner, it helped out my idle and cold running, and I figured out that it was because the cleaner had cleaned off the spark plugs a little. Now if I start to have problems like that, I replace the plugs, and it fixes it.

Greg

I had no earlier post.
I took that rough shifting issue as a design flaw.

This hard shifting N to D for example feels
as if another car is bumping in my rear bumper.

I think something on the driveshaft has worn out.

The valvoline "fuel injector cleaner" cost 4 $.
The valvoline "fuel system cleaner" cost 10 $.
Don't know the differences. May be concentrate?


1986 745 ZF4-HP22

I agree with WJW, the hard shifting thing is very often due to worn out bushings. Most notably, the torque rod bushings, and the axle-to-trailing-arm bushings. (I don't know if the axle bushings in the 740 last longer than the 240)

With worn out bushings, when you shift from N-D-R, or whatever, it often does feel like you are getting hit in the bumper.

Check the bushings, change them if necessary, and also check for play in the driveshaft U-joints. Not hard to do.

As for the 2 cleaners, I would think they pretty much do the same thing.

Greg

This sounds obvious but did you check your ATF level? Low fluid might cause that. Has it been changed lately?

It could also be a universal joint in the driveshaft. Do you hear a click/clunk sound after the shift?

I'm no bushing expert but I believe people on this board have said that bad rear bushings might exhibit similar symptoms.

Good luck!