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Trasnsmission Concern


hammo400
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Hello,

I'm new to the Club as well. I have a couple of questions about LS 400 transmissions / electrical system.

I have a 1991 LS400 with 105,000 miles. I have noticed - or this may be my imagination - that as I'm at speed on a level highway that when I take my foot off the gas that the speed seems to reduce quicker than expected. I've checked the brakes for rubbing -NO.

If there were something rubbing in any part of the tranny, would I know it ? I don't hear any noises when shifting nor feel any slippage and the tranny shifts smoothly and quietly. Could it be as simple as the axles need greasing ?

I also noticed that on the highway when I was at 120 mph that a little smoke seemed to be coming from the gearshift console. It went away at sub-100 mph speeds. What could be rubbing as the driveshaft rotates faster ? Again, no noises. Also, If there is too much transmission fluid in the transmission, what are the effects ? Could this be the cause of the tiny bit of smoke? Could something be burning /melting on the driveshaft - undercoating, maybe ?

The car is insulated so well, I could have a bon fire underneath and not know it.

Re the electrical system. My cruise control has stopped working. No light comes on the dash when I press the button on the steering column and the system doesn't engage. I'll check the fuse, if it's not this , what else could it be ?

Any comments would be much appreciated . They can also be sent to my regular e-mail : <gregehammond@yahoo.com>

Thanx

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I would have the trans checked for fluid. It may even have a small leak on the rear seal between the motor and it. I am not sure if this will cause to slow quickly, but will cause some minor smoke at high speeds. In the long run you could loose or bind a gear. Under coating should not be in that area? You are not slipping or missing a gear so if you act quick you may find a minor fix..... I am leaning toward a seal going out or leak/ low trans fluid. It would not hurt to have the (rear end) seal checked while your at it. it could cause some binding and may not notice the sounds..... Good luck and welcome to the group!

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Patruga,

I wasn't 'stretched ' at all. My pedal had a way to go before it hit the floor. I've had my prior '91 LS 400 easily into the 140 range without strain. The only scary thing is that if you don't look at the speedometer, you'll never believe you're at such speeds ! The windnoise does increase above 100 mph - not surprising.

The problem may be a seal that at high driveshaft rpms leaks some fluid , which, being in a high temp area, creates the minor smoke issue. I'm getting ALL the seals checked tomorrow and I'll let the Forum know the outcome.

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I just bought my '90 LS400 a week ago. I noticed that it didn't always shift down when taking off. It would stay in 2nd and shift up but it wouldn't shift down to 1st. I had my tranny serviced yesterday and the fluid levels were too high. I changed the filter, gasket and fluids. We noticed that the tranny fluid was burning a little too from the high level. Now it shifts like it should and I can use all the power.

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I have to go back in a week to drain and refill it again. It's because of the tranny fluid in the torque converter that needs to be flused through. I guess there is no way to drain the torque converter, just the fluid in the tranny at the pan?

The car ran great today... Jeez, these rigs get up and go. It's kind of funny on how this luxury ride has balls like that. hehe...

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ToddLS400,

That may be my problem. The fluid level being too high. I added 8 oz. of an additive for older transmissions to an already full tranny. I might need to drain a little. I checked the dipstick HOT and it's right to the top. The EXTRA may be what's causing the 'burn'. It can't hurt to flush the entire system.

Glkad to hear you got the power back and the smooth shifting you expect. Yeah! They do got some serious balls! I timed my 0-60 in the low 8's, not too shabby for a 13 yr. old automatic !

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Yeah, too much is not good. When oil heats up it expands. If it has no where to expand then it burns. The mechanic said he could smell it when pulling off the pan. It must shorten the life of your tranny if you leave it overfilled? Too much heat is never good.

Maybe the same company that makes the "wetter fluid" for radiator cooling makes the same for trannys?

Low 8's from 0-60? Wow, that is great. Did you do the 1/4 mile at your local raceway? I wonder if these cars would do about 15 or 16 sec 1/4 miles?

Check out this guy's LS400 Twin Turbo site> http://www.lextreme.com/

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ToddLS400

I had the tranny flushed and re-filled. It was 1/2 quart too full. This should solve the minor smoke problems at high speeds, though I don't know when I'll be able to get it into the 120's+ again. I don't have a track close by to do a 1/4 mile run, but may take the car to one when the weather warms up. For the hot months, I put Mobil 1 10W 30 full Synth oil in the crankcase and Mobil 80W-90 LS full synthetic in the differential.

An interesting note: The tranny flush and refill only used 2.2 quarts of the Type T-4 Toyota tranny fluid. The mechanic told me that the entire tranny holds 12 quarts and that to flush the entire system was called a "Full Transmission flush" and would cost around $275.00. I knew there was extra fluid in the torque converter etc., but not 9.8 quarts !!! I will have to get this done at the next 60 K check. I have already bought 15 quarts of the tranny fluid from Toyota at a substantial savings than through Lexus - all I have to pay for is the 40 minutes of labor.

I would do these routine light maintenance things myself, but if you get Lexus to do them, they give you a 12 month warranty. This, to me , is worth the labor cost if I supply the materials.

I have already purchased all fluids, belts, hoses, plugs, filters, pads and valves for the 60 K check. All they will charge me for is labor - 5 hours at $80.00 / hr. This major tune-up should keep her happy for another 12 K (except oil changes). Under $500.00 for this is MUCH better than the $1,100.00 a local dealer wants for the 60 K check-up.

Any word on the kick-down switch under your pedal ???

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Yep, same as me. Too much fluid by whoever serviced the car last time.

Yeah, I think the kick down switch is faulty... Or maybe I need to do a few more tranny flushes to circulate out that old burnt fluid? I was suppose to go there today to do another tranny flush and refill. I hope he only charges me for the fluids?

I haven't been able to drive it that much due to the starter going out. I've been driving my company car, a 2003 Chevy Impala. Not a bad car. I'm actually putting the Lexus in the shop next Tuesday to have the starter fixed. There is major labor getting to the starter. The mechanic at my local shop about a 1/4 mile up the street said that the contacts in the Lexus starters go bad eventually. I told him the symptoms and he said that is pretty common. My actual starter cranks fine when there is full power to the unit. He said there is metal contacts in the starter that wear, so when you try to crank it will not pass current all of the time. Sometimes the contacts will pass power to the starter when engaged and it'll start or it will just click. That's my problem. It'll cost me about $400 total parts and labor (mostly labor). That's better than the $700-800 quote from a few other shops. I actually got a $500 quote from a Start Mart, "alternator/starter specialist". The guys in the shop looked like they were all on CRANK. I don't want those tweaked out losers ruining my car. I heard Lexus dealers charge $1,600 for a new starter and labor in the service shop. What a joke! You also have to replace a few of your manifold intake gaskets since they have to disconnect them to get to the starter. It's a friggin' labor nightmare changing the starter in these cars.

Thanks for asking...

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