I didn't do a flush we changed the transmount, transmission filter, gasket and 5 qt's of Type IV. so my trans is smooth. The only jerk i get is from reverse but my mechanic says that might be the u joint apart of my rubbing sounds that it might be causing.

 

Lots of good info guys!

I just drained some more fluid and replaced. Didn't have time to mess with the transmission pan so I only drained and refilled, I have not replaced the filter. Anyway, when I did the refill this time I added a bottle of Lucas Transmission Fix in place of 1Qt trans fluid. I don't know if that helped any but the transmission shifts a lot better through the gears whereas it used to jerk and seem to slam into gear.

It always shifted fine while driving, it was going from Park to Reverse to Drive to Reverse to Park when it would have the hard shifting. At this point I would say that it is 90% better. It still shifts a little hard every once in a while but no where near as bad as it was.

I am satisfied at this point with the improvement that the fluid transfusion has accomplished.

 

Time to revive this old thread. Put my 93 SC400 in the shop to have the oil leaks sealed up. They pulled the engine and trans. to do all the gaskets besides head and intake. My cars trans. has been serviced reguarly and with Toyota fluid. I already have a new trans. mount and the car always shifted smooth with no jarring. Since I got it back it shifts very hard into drive and less hard into reverse. I tried adjusting the TPS CCW and lessening the tension on the detent cable with no change. After reading the post about unhooking #4 solenoid plug, I am going to look and see if maybe its unplugged, the shifts through the gears do seem firmer. Also make sure my trans. mount bolts are tight.

 

If you can, check your differential bushings. It's probably one of the next things I'm going to do to remedy this jerk into drive. Aliga sold them for $120 but I don't know if he still has them.

 

Odd thing for me is, my car did none of this before it went into the shop. Monday I will be able to jack it up and check things out.

 

Ive checked for a pinched detent cable and unplugged sensors, can see nothing wrong. If someone was smart enough to post a micro fische type drawing of the SC400 trans. showing the location of all 4 sensors, that would be great..

 

Does anyone think a vacum line unplugged or kinked could cause my car to shift into drive hard. The car does idle and run normally.

 

My trans. is not so bad shifting into reverse, but harsh into drive. I had my steering rack bushings replaced while it was in the shop.

 

Checked my sub-frame bolts, steering rack bolts and trans. mount bolts, all tight. Im sure I have all the symptoms of the 4th. solenoid unplugged. Hoping someone can please post a drawing of the auto. trans. and the solenoid locations.

 

Ive been over most all of my car, and this is what I believe is going on with my complaint of hard shift into drive. When my engine and trans. were removed the wiring harness was unplugged from the sensors on the trans. When the 4th. or front sol. which is for shift smoothness was unplugged ,the plug clip broke. This has been reported by people unplugging them to achieve firmer shifts. I run into this prob. in my business with anti-weather
pack plug- ins. The rubber seal in the plug keeps the connectors apart because the clip is gone that pulls the plug onto the part being plugged into. If you cant zip tie the broken plug tight the connections will not be made.

 

Unlikely theory, IMO. I had the hard shift into drive before and after the solenoid mod. The mod 100% changes the behavior of the car, so the connector has to be doing its thing and the solenoid isn't playing any role in it. It's possible that there are multiple things that can create the exact same symptom, with the solenoid mod being one of them, but like I said, I consider that unlikely.

 

T2D2 I agree to disagree with you. The last line I meant to put on that post was, If you jimmy your plug loose on #4 trans. solenoid, there is a 90% chance it will not properly plug back in poperly. I have had new alternators that would not charge at all, but if you apllied extra force to push the plug in all the way, it would work perfectly. Usually something not lineing up in those instances. A broken plug clip would def. keep a weather pack plug connector from connecting.

 

I'm not disagreeing that a worn out plug could cause a bad connection. I'm saying that I haven't seen a pattern to the solenoid mod and the common hard shift into Drive behavior, so that plug being bad doesn't seem like it would have any bearing on what you're trying to solve.

 

The plug was broken and the hard shift occured at the same time. Could there have been something else, maybe but I feel that Ive checked the other possabilities. Also their is a black boot that covers the plug on #4 sol. that has LOCK printed on it in red letters.

 

Does anyone know if there is an o.e. replacement plug for the front #4 trans. solenoid?