s14a

Hello lads,

New to the forum and having a ruff time with my daily. Hopefully you guys can shine some light,

Anyways,

I have a 91 ls400. It's been performing perfectly fine up until yesterday, when I got into my car, started driving, and then noticed that it wouldn't shift to 2nd, 3rd, and so on. It is stuck on 1st. No matter if I put it in L, or 2, it still is stuck on 1st gear.

What I have done so far:

-change the transmission fluid with Toyota type IV

-Drop the pan, and clean out the filter, then again refilled with new Toyota type IV

I'm stumped. The original fluid in the car was nice and red and filled to the proper level. When I dropped the pan, the magnets were nice and clean (no metal fragments).

I have no check engine light on, or any other lights on. WHAT CAN IT BE?!?! I'm out of ideas.

I really hope you fellas can assist me on this one.

thanks in advance!

LScowboyLS

is the speedometer working?

(this is very important due to the speed sensor)

s14a

Speedometer does work. RPM does not, however, that hasn't been working since before I bought the car.

LScowboyLS

can you scan this car for codes and datastream (gear position MLPS and gear requested)

the good news is, this type of problem is almost never a deep (rebuild the tranny) internal issue

s14a

Car to elaborate on the " datastream (gear position MLPS and gear requested)"

Not sure what you mean by that. There's an auto parts close to me where I can borrow a scanner but will that give me the information I need? Like I said, no check engine light, or any other warning light is on.

BTW the car goes in to reverse and neutral perfectly fine

LScowboyLS

that would be if you have access to a more advanced scanner

I would say this is 99% chance either a speed sensor, gear position switch, or ECU issue

can say about 99% it is NOT a problem inside the transmission, this is a control issue, but if it is internal, it is likely a solenoid

can you drive it in D and run up to 40 mph and back off and coast and see if you can get it to go into 4th gear OD

s14a

I can get it up to 40 but when I back off and try to give it gas again it's like it goes into neutral. I have to either wait for the car to get to a complete stop, or rev it real high. It will grab on when I rev high.

LScowboyLS

ok, your test result has essentially ruled out a shift solenoid being the issue, so it is now approaching a 100% chance of the problem being outside of the transmission itself

now I need to know whether the gear selection lights in the instrument cluster are correctly showing the gear selected in each gear as you manually move the shift lever

s14a

But you talked about getting into 4th gear O/D. I can't though. This is me still driving in 1st gear. I start driving, (stuck in first) and when i let off but gas it again, it just revs like it were in neutral. So in order for the car to drive again, I have to rev it real high 4-5k plus, or get to a complete stop and drive again. As for the shift leveler and the cluster, yes; they work correctly as I move the shift leveler.

LScowboyLS

I will have to study the control wiring, but a speed sensor or ECU are looking like probable candidates

the ECU capacitor fix is dirt cheap, about $10 and a few hours of pretty darn easy work, the ECU may fix it or may not, but sure is a cheap option that needs to be done anyway!

s14a

Well if the speed sensor is bad, then wouldn't it stop reading my speed? My mph work. RPM doesn't, but I think that's related to another sensor. And the leaky capacitor, well I've read up on that and seems pretty common. Would it be hard to locate my ecu, pop it open, and visually inspect it?

Also, is their a separate ecu that controls the transmission? Or is it the ecu itself that controls everything?

PureDrifter

iTrader: (10)

when you shift the car into drive or reverse, does the corresponding light on the dash light up?

if not or if it goes haywire you may wanna take a look at the infamous trunk hinge issue, though i kind of doubt that's the issue here.
http://www.lexls.com/tutorials/lighting/bulbout.html

LScowboyLS

I believe in your year of LS400, the speed sensor for the transmission is a separate sensor from the one for the gauge

not that difficult - about 15 minutes of work removing lower glove compartment and ECU using the diagram and instructions here - sometimes bad capacitors are not obvious from visual inspection, but commonly they are.

on LS400, the ECU controls the engine, the transmission, and the A/C

s14a

Ok well I checked the capacitors (8 of them) and all seem to be fine. No leaks/corrosion. Except for 1 which I'm not sure if it's normal but it's literally stuck to the brown globe shaped thing next to it (not sure what it's called). Here's the pic:



and this was also stuck together (but it's not a capacitor?)




Also, going back to the speed sensor. I have researched it's location but there isn't much info on it for some reason. Anyways, where on the transmission can I find it? I wish I can get codes off this car but I have no fancy scanner like I mentioned earlier. At most I can get a small pocket OBD scanner.

I'm running out of things to check and it's getting frustrating being without a car

I went to a transmission shop where my friend got his Nissan Q45 tranny rebuilt and the guy just basically insisted that he was just going to rebuild it, quoting me at 900 bux just because I seemed desperate. Screw that. He can rebuild it 10000 times with unicorn blood. If it's electrical, that will not fix it. Man do I hate shops. But at this point I'm ready to throw in the towel.

LScowboyLS

well don't throw in the towel, and whatever you do, DO NOT let anyone rebuild your transmission - that is not where the problem is!!

I would redo the caps, because if you have a little bit of patience and can solder, you can quickly eliminate one of the more likely suspect causes for a $10 investment, I cannot tell you the magical way to find an honest transmission man, the only one I know is near Denver, Colorado

I will check more into the speed sensor

PS - neither of your pics are showing ANY of the 8 capacitors in question - they look totally different than the ones in your pic, they look like these