RSTSpeed

iTrader: (4)

Here's what's going on:
1993 SC300 Automatic. Right about the time it started to get cold here in East TN., my trans would clunk REALLY hard when shifting from Park to Reverse when the motor/trans is cold. I know that if it's not warmed up, if will shift into gear a little hard, but this is so hard it makes me cringe; it's not right.

Secondly, shortly after it started slamming into gear, it would stick in gear (not wanting to shift up from 1st to 2nd gear. Lately, it's been getting even worse, hanging in gear even longer and sometimes sticking in 2nd (not shifting to 3rd) and has even slipped out of gear once.

My mechanic tore the trans apart and said it looked nearly perfect; the filter was a little dirty, but there was no metal in the fluid, gears weren't worn, etc. While he had it open, he cleaned and "rebuilt" the valve body, so I doubt that's the problem. I replaced the speed sensor, that didn't do anything. There is another sensor of some kind located above the speed sensor on the transmission - my manual shows it, but doesn't list a part number for it. Anybody know what it is or what it does?

What the hell is going on?!? I'd really like not turning 4,000 in 1st gear to make it shift.

Thanks for the help everyone!

deneb

Very Interested - I'm having a nearly identical issue with a 93 SC400. I've tired a replacing the transmission mount along with the fluids and a filter, but I'm still basically crossing my fingers that it doesn't have to be opened up.

Came across this just a bit ago http://www.youtube.com/watch?v=n3-DfW2ouGA and think it might help but I only have the adjustment numbers for the V8 and haven't tried it out yet. Was also reading on having the the shift solenoids checked and replaced too.

Please update if you do happen to figure the deal tough, I would love to know just what the hell is going as well.

RSTSpeed

iTrader: (4)

Will do, and thanks for the video! I'll look into that a little more before I start messing with it.

I forgot to mention that when the mechanic opened up the trans. he replaced all the solenoids, too (three of them I think), so that's not it either... at least for me.

stockhatch

iTrader: (12)

I dont know how line pressure is controlled in these transmissions, but if I am not mistaken there is a cable from the TB to the trans. It may control line pressure, or just be a manual kickdown, but it may be worth looking into its adjustment.

RSTSpeed

iTrader: (4)

OK, cool, I'll look into it.

Ali SC3

iTrader: (10)

yeah, you may need to adjust the cable, sometimes over the years they can get a little slack in them, same even with your actual throttle cable. there are also some threads about making the autos shift firmer that seemed popular a long time ago.

SCV8

Your stuff is getting old, wearing out. Start looking for a reasonable replacement.

RSTSpeed

iTrader: (4)

Care to be more specific? The trans has @ 130,000-150,000 miles on it, btw.

JDMSCVIP

Does this apply to the sc400? My tranny slips and when I turn the car off it'll stop for a few min. N begin to do it again??

RSTSpeed

iTrader: (4)

Update: I just replaced the No. 1 Speed Sensor on the transmission (I've had the flu allllll week, so I just now got to fixing it). On first test drive it APPEARS that the problem is solved. I let it warm up for 3 or 4 mins (temp gauge was still bottomed out on cold) and it shifted into gear normally, and better yet shifted thru all the gears perfectly, even from 1st to 2nd under WOT!! I'll let it get cold again and drive it tonight, hopefully it doesn't slip or act up any more.

RSTSpeed

iTrader: (4)

I don't know for sure, but I'd assume the same applies.

deneb

Good deal RSTSpeed. I really hadn't played around much more until yesterday. The issues was almost gone after the filter change and the warmer weather here. I was actually surprised to see a difference and it made me wonder if it wasn't simply a clog. I've made myself a note to have the fluid flushed fairly soon just to be on the safe side.

The speed sensor makes a lot of scene though. After a bit of reading and a bit of playing, I think that may be part of deal here too. Resetting the ECU actually seems to help for a little while. I just need to spend a some more time on it before I can say on way or the other. I would like to know where you found you speed sensor. Ebay has a few take outs but I'd rather get electronics in a box if I can.

and btw - the TPS adjustment is more of a trick then a fix and I don't believe it works on the older SC300 at all. Mine appears to be in spec so I left it as is.

and thanks for your updates they've been very helpful

RSTSpeed

iTrader: (4)

Well, I was wrong. The problem is still there, I think it just faded away a bit because of the warmer weather. I think my next step is gonna be to try and source a ECM.nWe'll see. I originally thought the problem was electronic, but if it's changing with the temperature then maybe it is something mechanical, but I have no idea what. Any ideas anyone????????

I got my speed sensor of my old transmission. I was MUCH cleaner than the one I pulled out. *I got both sensor out of the old trans. the No. 1 Speed Sensor is the mechanical gear, and the other speed sensor (located a little below the No. 1) is just a solid black piece that I think is some sort of magnet. Not sure, though.

RSTSpeed

iTrader: (4)

Can anyone confirm that this is the transmission ECU? (The circled one):
*EDIT: Also, above when I said the transmission was slipping, I think I was wrong. It "slipped" last night, and instead of letting of the throttle I kept in it and it felt more like it was shifting up (to 2nd gear) to soon and then back down to first instead of in and out of gear. Very odd...

account2x

iTrader: (5)

That is the ABS ECU. Transmission ECU and the Engine ECU are one. You can see A/T for Automatic Transmission printed on it.