somnoboy

Interesting Transmission Question: 1992 LS400, 98,000 miles. Mint condition. Transmission fluid flushed by Lexus dealer about 2 years ago at 85,000 miles. Fluid used was Type IV. (Isn't Type II recommended for this engine?)

Anyway, recently had oil change done by local mechanic. While on lift, I noticed that the bottom of the transmission was wet. Also noticed a small bar under the transmission was wet, and practically (but not quite,) dripping with fluid. Checked tranny fluid while cold, and level is way, way OVER the upper HOT limit. Fluid looks very clean and red. Shifting performance is flawless, and typical Lexus smooth.

What is going on with my transmission?

JimsGX

Toyota type T-IV is the correct fluid. Is the leaking fluid oil or transmission fluid? Did you follow the manual's procedure for checking the tranny fluid level? It could be the rear main seal leaking if it's determined to be motor oil...

PureDrifter

iTrader: (10)

toyota T-II was superseded by T-IV.

ie-they dont make t-ii anymore since t-iv meets its requirements.

somnoboy

I actually didn't follow the manual procedure when checking. I simply checked the tranny dipstick before the first drive, and saw that clean red fuild all the way over the full HOT level.

The local mechanic (not a Lexus expert) thought it might be the main seal.

I'm thinking of taking it to the Lexus dealership for an estimate, but am almost afraid of what that estimate will be. This looks way more involved than anything I, a total non-car guy, could do DIY.

JimsGX

Look for a reputable transmission shop in your area. If it is the rear seal, the transmission will need to be removed. It isn't that big a job really. Parts are under $100. I'm guessing labor would be 4 to 6 hours.

somnoboy

Thanks for the tip, Jim. I think I will do exactly that. I might still bring it by the Lexus dealership for an estimate for comparison purposes. I'm quite fond of this car; I'm the original owner. I don't ever want to sell it.

rob22

Pardon the dumb question...you're checking level with the engine running, correct?

lexls.com tutorials has a pic of a leaking rear main. You'll want to replace the tranny mount at least, perhaps even the EGR tube if you're having a shop drop the tranny.

Rob

trukn1

1.. are you sure it is trans fluid leaking and not something else?
2.. is your power steering pump leaking? Power steering fluid will not only get into the alternator but completely under the entire underside of the car while driving. Have noticed this many times before I had my PS replaced.
3.. What color is the fluid itself? Red?? Black?? Clear like?? The fluid color will be the key sign to figuring out what is wrong. Rear main seal not being excluded here.

somnoboy

Not a dumb question. Actually, I just checked the tranny fluid level before the first drive of the day. (The engine was not running.)

I did look at the lexls tutorial. It was very helpful, thanks. I am afraid that the dealer looking at this will "suggest" replacing the tranny mount and EGR as well. This is why I'm frankly dreading getting an estimate for this.

somnoboy

1. Not positive as to what fluid. Will get it on a lift today to check color here.
2. Don't know if p/s or not. Will find out today.
3. Not thrilled with the thought of having to replace rear main seal.

JimsGX

Somnoboy,

What motor oil are you running? Dino, synthetic or blend? Did you change brands of motor oil recently?

As stated, I'd consider a new EGR pipe when the transmission is dropped since its such a PITA otherwise. The tranny mount can be done at any time in 20 minutes. I wouldn't replace it until it's truly needed. With 98k miles, unless you have any symptoms, it's probably still fine.

somnoboy

Jim:

I switched to Mobil 1 synthetic 5W-30 at 94,000. Prior to this, it had been on straight dino oil always at the dealership every 3 to 5 thousand miles.

I noticed the leak a few weeks ago when I did another oil change, again with Mobil 1 synthetic 5W-30 at 97,000.

I got it on the lift again today, and had another look. Amazingly, the leak seems to have stopped. One can tell that a leak was there some time ago, but all that remains is dried oily residue. I wiped with a paper towel and it was black. I assume this means that it is engine oil, and not tranny fluid as I had feared.

Is the appearance of the main rear seal leak at 97,000 miles, and its sudden disappearance 500 miles later (after an oil change) somehow related/characteristic of a recent change to synthetic oil? Now I'm really curious...

Thanks for the tips/hints on the EGR pipe and the tranny mount. My local mechanic had a look and told me to take a chill pill. Yes, there obviously was a leak there, but there is no "drip rate." Just a stain. I guess I can not worry about having to replace the rear main seal for awhile?

JimsGX

Somnoboy,

When I tried switching to Mobil1 5w-30 from straight dino oil at somewhere around 85k miles (can't remember exactly but somewhere around that mileage) on my 91, I had a similar problem. After about 1500 miles on the Mobile1, my rear main seal started to leak. Then after another 1k miles or so, the leak slowed and then stopped. However, when I did my second Mobil1 oil change, it started leaking again. I switched to Valvoline Max Life Synthetic Blend. The main seal leak went away almost immediately and hasn't come back.

We have similar model years and mileage on our cars, I would recommend a change to the Valvoline Max Life at your next oil change.

Jim

somnoboy

Jim: Hey, thanks for the tip! I certainly will switch to the Valvoline on my next oil change. One question: I assume you are still at the 5W-30 weight?

You are certainly right; our two cars seem to be almost identical model/engine/age/mileage. Any other tips you can pass along on these beautiful, wonderful cars would be greatly appreciated.

From one old LS400 to another. Thanks!

JimsGX

Yes... Valvoline Max Life 5w-30...