my honda civic has trouble going into reverse. why?

April 16, 2011 6:14 PM

our 2006 honda civic EX sedan (automatic) is having occasional problems shifting into reverse. we're taking it in to be fixed, but i want to try and read up on this beforehand. fascinating details inside.

the day after our blizzard (we're in chicago), the boyfriend got stuck on a snowdrift.

the front end of the car was stuck with packed snow underneath, so boyfriend basically had to dig out and back off of that in reverse (that being a summary of about two hours worth of effort), which caused some damage underneath.

firstly, a plastic shield was ripped off from the undercarriage/front bumper. that's like a hundred bucks to replace, so i don't care.

secondly, the car will occasionally refuse to go into reverse. when put into reverse, it'll act like it's in neutral and just rev.

we can make it drop into gear, but it's not really safe—we have to either shift into drive then back into reverse until it drops into gear, or gun the engine in reverse until it catches.

it'll drop into gear after about three tries of either method. this only happens with reverse, none of the other gears.

during driving after it's needed to be forced back into gear, it'll jump somewhat as it shifts between other gears. (this happens every time, so i assume that to mean it's connected). it feels like something slipping for about a quarter-second before changing gears.

what does this sound like to car folks? i'm not sure what portion of the engine to familiarize myself with. ultimately, i'm going to trust a mechanic making repairs, but i do want to have a general idea of what we're getting into before taking it in.

posted by patricking to travel & transportation (5 answers total)

Not a mechanic, shade-tree or otherwise, but I do listen to CarTalk a lot! Sounds like a transmission issue which can mean expensive :(

My completely wild guess based on knowing not really much about cars is that you somehow stripped some of the teeth on the gears in your transmission or maybe your transmission fluid has all leaked out and caused things to wear badly.
posted by ghharr at 6:25 PM on April 16, 2011

I'm wondering if the shift linkage got tweaked when he hit that snow. If the linkage is just slightly bent, the transmission may not be going all the way into gear. An alternative may be a bushing in the linkage may be bent or missing. Same situation. The shift does not get it all the way into gear.
posted by Old Geezer at 6:44 PM on April 16, 2011

Have you checked the fluid level? I have seen that happen where the fluid level is right at the edge of too low, and wouldn't go into D or R, depending. Your other description of revving it and dropping it from D to R to make it catch is exactly what low fluid acts like.
posted by gjc at 6:59 PM on April 16, 2011

Getting stuck in the snow can be really hard on an automatic transmission. I imagine there was a lot of revving, gear banging, and wheel spinning.
About a month or two ago, we had a big blizzard here in Philly and our shop was swamped with towed in cars which all needed new transmissions. Over the next couple weeks, I think we must have done about ten transmissions.

An automatic transmission is kind of hard to explain without visual aids. Suffice it to say, there aren't five gears inside the gearbox. There will typically be two complex planetary gearsets and the automatic transmission controls power flow and gear ratio by controlling which portion of the gearset is the drive or driven gear, allowing multiple ratios to be achieved in a relatively small package. It uses the transmission fluid as hydraulic fluid. Computer controlled valves direct that fluid to clutch packs (multiplate wet clutch assemblies) which use friction to direct power flow through the planetary gearsets. Excessive high temperatures and high RPMs can cause these clutch packs to deteriorate and loose their friction properties. So now, when the computer directs the hydraulic pressure to that friction actuator, it just slips and doesn't engage the gear. The hydraulic pump is driven by the transmission input shaft. So revving up the engine boosts the hydraulic pressure in the transmission and when you dump it into reverse, those weak and slippery clutch packs have enough pressure behind them to engage somewhat.

Check your transmission fluid. It should be bright red and not stinky. I'll bet that the transmission fluid in your car is dark and smells pretty bad. You're probably going to wind up needing a significant transmission repair, if not a complete replacement.
posted by Jon-o at 7:08 PM on April 16, 2011 [1 favorite]

thanks for the suggestions so far, folks. i'll start researching.
posted by patricking at 7:58 PM on April 16, 2011