1994 Transmission****** from neutral to drive

Tiny
JKBHEAT
  • MEMBER
  • 1994 LEXUS SC 400
  • V8
  • 2WD
  • AUTOMATIC
  • 160,000 MILES
*PLEASE HELP ASAP*
I'm a college student and have classes starting January 10th and I already spent a ton of money on this problem. Thanks in advance!

What can be the cause of my 1994 Lexus SC400 roughly shifting******** into drive from neutral/park? It also****** going into reverse but it is usually not as bad.

Several weeks ago my car started (just once in a while and usually when the engine was cold) to have a delay (3-5 seconds) when shifting from park to drive, after the delay the car would abruptly shift***** very hard into gear. After that, it would work fine while driving, going through all other gears. I thought these might be symptoms of low fluid so I added a little bit of fluid and some lucas additive. The problem improved for a week or so but it continued to periodically happen and then a whirring noise began every time the car started. This sounded exactly like a power steering fluid problem so I focused my attentions there. Long story short, one day the transmission completely failed.

A friend of mine recently swapped his sc400 engine and transmission (~87,000 mi and working great upon removal) for a supra set up. I bought his used transmission from him and had the shop that my car was towed to swap the tranny in. My car is a 1994 and his car is a 1992, I'm 100% sure that these transmission are 100% the same. I get the swap done and leave the shop with my car satisfied as everything was working fine. But halfway home I realize that the Check Engine Light is on; I'm worried a little but not too much as the car is running great and I'm sure that swapping the tranny may have tripped something that is not really a mechanical problem.

Later that day I try to take the car for another test drive but like before when shifting from park to reverse or drive there is rough jump***** (but there is no delay). After shifting to drive the car shift great through all other gears but I'm worried that a complete failure is going to happen like last time. So I talked to the shop that swapped the old transmission out and they assured me that the problem is not related to the old transmission failure. They said that the old torque converter blew and the filter was clogged (the whirring noise was the tranny starving for fluid). They said it was problem a sensor related to the check engine light causing the rough engagement.

So, since my car is obd1 I checked for any error codes myself by jumping the two appropriate slots on the diagnostic port (I successfully have pulled codes from this car before with the same method). During testing the O/D light flashed continuously at a set interval (which I'm pretty sure means no error codes) and the check engine light stayed completely solid (though I think it should blink continuously, I think that this also means no error codes. This leads me to believe that the "CEL" being on all the time (even after resetting the ecu) is just a product of a minimal difference from the tranny swap but there is no actual problem/code.

The shop also said that the idle may be jumping causing the rough engagement. The car idles at 650rpm (exact oem spec) and when it is shifted into drive or reverse the rpms jump to 700-750 and then immediately goes down to 600-650. Does that sound normal?

Extra info:
* The shop said that the only thing that was re-used from the old transmission was the neutral safety switch.
* The shop used a remanufactured torque converter that they bought.
* The fluid after I drove the car for about 30 min. Seemed to be a quart over the top "hot" notch
* Only once with the tranny was there a delay from park to drive; it was only about 1.5 secs and the car was really cold.
* The***** gets better after the car has been driven for a while but it still very noticeable.


What can be causing the rough engagement into drive/reverse?
Do you
have the same problem?
Yes
No
Tuesday, January 4th, 2011 AT 8:26 PM

4 Replies

Tiny
DOCFIXIT
  • EXPERT
Need volt meter key on measure voltage from E1 to TE1 and TE2 on both DLC #1 and #2 ues E1 as ground see diagram post results
Was this
answer
helpful?
Yes
No
Wednesday, January 5th, 2011 AT 3:24 PM
Tiny
JKBHEAT
  • MEMBER
Ok, I haven't drove or started the car in about 2 days. When I started it the CEL light was not on. Shifting into drive was not as violent as usual but there was a brief (less than second delay). I drove it around my neighborhood for about 10 mins ( 30 mph) and still no CEL light. Once I went outside of my neighborhood and picked up speed (40-50mph, over 3k rpm), the CEL immediately began to faintly flicker, like a bad bulb, and then the CEL light turned on full and bright.

Before I drove it I got the voltage measurements as you requested. One thing though, is that I never used DLC 1 before and when I opened it all the terminals were covered in a greasy substance that resembled peanut-butter. I don't know if someone put some kind of grease there to protect the terminals or if something burnt (being so close to the engine). Anyways here are the results:

KEY ON:
Battery - 12.45v
DLC1 - TE1: 11.59, TE2: Couldn't get a reading
DLC2 - TE1: 11.57, TE2: 11.91

ENGINE ON (Car Started):
Battery - 14.46v
DLC1 - TE1: 14.04, TE2: Couldn't get a reading
DLC2 - TE1: 14.00, TE2: 14.33

I couldn't really see it clearly because of the substance referred to earlier but when I was checking inside DLC1 (TE2) it didn't feel as if I was hitting a terminal.
Was this
answer
helpful?
Yes
No
Wednesday, January 5th, 2011 AT 5:17 PM
Tiny
DOCFIXIT
  • EXPERT
Test where to see why MIL or CEL light stayed on and not flash so from results indicates faulty PCM. So that would be why symptom followed to replacement trans. Peanut butter is to protect terminals from moisture/corrison
Was this
answer
helpful?
Yes
No
Wednesday, January 5th, 2011 AT 6:11 PM
Tiny
JKBHEAT
  • MEMBER
Could you clarify what you meant by the first sentences?

And I have another ECU that I swapped out because (after a year of pulling my hair out) I found that it was the cause of my battery draining quickly; it was making a relay stick but when I disconnected the negative battery cable to test the fuses/relays for a draw the the relay would un-stick (leaving no symptons of a draw).

Anyways a couple of days ago I put the that ECU in my car and there was no CEL. I didn't drive it around to test if it would come back on but I shifted through the gears a couple of times and it was still slamming into drive/reverse. When I put current ECU back in, the CEL light was immediately back on. Should I drive it around with the faulty ECU (sticking relay) to test if the light will come back on?

Oh, and when I jumped DLC2 (E1 and TE1) with the old faulty ECU in both the CEL light and the O/D light continuously flashed; meaning there were no codes.
Was this
answer
helpful?
Yes
No
Wednesday, January 5th, 2011 AT 6:44 PM

Please login or register to post a reply.

Recommended Guides