I'm new to the forum...and new to working on Hondas...so bear with me please ;-)

I just finished swapping the bad automatic transmission from my son's 2001 Civic LX with a used one purchased from LKQ Salvage. The torque converter was included with the used tranny. Everything seemed to bolt together smoothly. Drive axles seem to be seated completely against the tranny housing. I filled it with Honda fluid and started the engine. Upon the shifting out of Park... there is horible grinding noises coming from the transmission, even while in neutral. I lowered the car to the floor and tightened the axle nuts and discovered that the care will roll while in Park!

Any help would be greatly appreciated! Thanks!

 

No clue, but are the driveshafts seated in the transmission gear box for sure? Although that shouldn't matter in neutral i guess.

 

The axles are seated. I removed the shift cable and made sure the tranny was in Park and the front wheels are still able to be turned freely.

 

Could be you bought a faulty used transmission.

 

That's what I'm afraid of.... Just didn't have the money for a reman tranny. I'm in the process of pulling the tranny now. Is there something that I might have done/not done to cause the car to be able to roll in Park?

 

It may just be the transmission and not necessarily something you did or didn't do.

Example:
A friend accidentally snapped the parking pin in his transmission. His truck would roll away if he didn't park with his tire(s) against the curb.

 

Update...installed another used tranny. I also changed the timing belt and tensioner, water pump and reset the valve clearance while the car was available. Started the car and it ran smoothly for about one minute then the idle started hunting up and down. Figured it was probably air in the coolant system, so I left the radiator cap off and turn the heater on full while the car ran for about ten minutes. Both radiator fans were running. After about ten minutes the idle starting hunting faster than before and the coolant started rising in the neck to the point of overflowing. I can't find any vacuum leaks anywhere of sensors unplugged. Stumped...

Suggestions?

 

It might be fine. When I changed mine , at start-up the idle was very unsteady for the first 10 minutes or so and the check engine light came on. I let it run for a while and rebuild it's memory (I guess) on the air, fuel, etc. After about 10 minutes I cleared the code and it ran fine. Did you try driving it?

 

I tried driving it, ran it with the cap off for another ten minutes, pulled the ecu fuse for the idle "relearn" process.... No change. Can't find any vacuum leaks anywhere.

 

Problem solved. I found a hose connection under the intake area on the back of the engine that didn't have anything attached to it. When I pulled the engine/transmission and unhooked all the lines, I tucked this one behind some lines on the firewall so it would be out of the way. Once it was hooked back up...no more surging idle! Test drove it and the second used tranny seems to be good...for now.
Thanks everyone for the help and suggestions!