Alright, I just signed up here and picked up my second G! a 05 coupe 5AT (stock) with only 90k miles. I got it for a steal but it does need some work. The trans being the biggest. First off I'm getting Engine Code P1736 (Shift Motor Open) I searched this code in G35's and wasn't able to find anything on here or google. When I take off from a standstill, The car is slipping, struggling and underpowered. When I finally get up to speed its revving high (3200rpm @60mph). The entire time getting up to speed I do not hear it shift once (might only have 3rd or 4th im guessing?) I of course checked the trans fluid first and it is full and still clean (not brown/burnt) Now I have tried putting it in manual mode. The gears light up accordingly but do not change how the car drive or shifts Ive tried downshifting and upshifting while driving and it does nothing at all.

Is there any possibility this could be a transmission computer that would either need to be reflashed or replaced?

Help is very much appreciated!

 

No it's probably the clutches or brake sleeve are burned up and someone did a couple tranny flushes to clear out the fluid so it didn't look so bad.

Take it to an independent reputable transmission shop for verification but the big giveaway is the slipping, that only occurs when the clutch packs are shot.

Be careful because usually when it gets to that point the whole thing catastrophically fails and leaves you stranded on the highway. My guess is you have under 5 miles left on the transmission.

 

Actually, first thing you should do is just check the transmission fluid level, if it's low it will exhibit the same symptoms but I really doubt any car dealership wouldn't have fixed the issue if it was just low fluid.

Make sure you know how to actually check transmission fluid level if you've never done it before, it's not the same as checking crankcase oil level.

 

Really? Damn. I mean, I think its slipping due to the fact that its stuck in 4th and taking off in fourth. Once im on the highway and put the pedal down it doesnt slip. I drove the car home this way and it was a 100mi trip. The engine code reads shift motor open?

 

Ohh in that case I'm a bit stumped, when the lower gear clutch packs or brake sleeves are shot you don't even get into the higher gears because it can't lock up the planetary gears.

That code isn't a valid 2005 G35 code, put it on a different OBD2 scanner and see what it says.

It's possible it's all in the valve body and you have a line pressure solenoid for 1st gear that's just not opening fully.

 

Alright I will grab another obd scanner and see what comes up. That was the only stored and pending code. I don't want to drive it because I know its just slipping the clutches and killing itself trying to take off in 4th all the time and I highly doubt 1,2,3 and 5th gear are all shot. It literally sounds like someone riding the clutch in fourth to get it to take off. I checked fluid while hot and running (is there a different way with these cars?). Maybe I will start by dropping whatever is in the pan and refill the same amount with new fluid? Thanks for the help so far!!!!

 

Grabbed another scanner. This one pulls up one code, P1764. I was able to dig up some info searching this code. Sounds like its either wiring or connection to the input clutch solenoid or the actual solenoid itself? Might be better off parting this car out if its going to need a new trans lol

 

Sounds like the valve body is shot.

Just for the sake of looking I would unplug the big electrical harness on the transmission and inspect it for corrosion or contamination with oil.

There is also a transmission ground on the front of the timing cover at the very top, two separate wires are grounded there, unbolt each one, use a brush to clean up the metal parts, bolt that back on.

I doubt it's a simple electrical issue like that but it's definitely worth taking a look before scrapping it.

 

Thanks for the tips Im going to check the connections this tomorrow!! Such a shame that it has trans problems with relatively low miles. My 03 sedan has 260k miles and the trans is flawless ( 6mt )

 

did you fix this??