I have a 2004 Civic EX with an automatic transmission. When put into drive and step on the gas, there is a clunk. The transmission works well after the initial shift into drive. It does have a problem going into reverse and back into drive from reverse will have a clunk again.
It has 99,000 miles, trans fluid is fresh DW1. All shifts are smooth with no slippage. It gets 40 mpg on highway driving.
I have gone over the entire front end suspension, and all control arm bushings, ball joints, tie rods, drop links are good. No problems with struts, new axles.
The only problem I can think of is old engine and transmission mounts. Would it make sense that the mounts could be the problem? The car has no codes when checked on the scanner.

 

Engine mounts have been known to go bad on these cars, so you may have a worn mount.

 

I'm hoping it is the engine and transmission mounts. I would hope there is nothing wrong in the transmission. I have not found any transmission problems that have this issue in my searches.

 

It turned out to be play in the splines of the axles and front hubs.

 

Since the axles are new, the front hub female splines were shot? Did you replace the hub or just torqued the axle nut?

 

I intend to replace the hubs and bearings. Currently tightened the axle nut to eliminate play, but not sure how this will affect the wheel bearing due to higher than specified torque.

 

There should be some loose tolerance fit on both the male and female splines so they can be assembled without beating on the axle shaft spline. Usually tightening the axle nut should take off the slack between the axle male spline and hub female spline. It should not affect the bearing as the torque is applied to the bearing inner race.
Are you by any chance the same E Sully posting on the 911 forums?

 

Yes there should be a small amount of slack for assembly tolerance, but mine was a bit excessive. It made a very noticeable clunk as the excess clearance was taken up, the axle nut was carefully checked 3 times after the new axles were installed. Currently the torque is quite a bit higher than specified, and the clunk is gone for now. I have to see what will happen with warranty on new axles.
Same E Sully. Love both my Civic and 911.

 

Good to know.
I also love my 964 and the Civic.