Front Differential / Automatic Transmission

[autodriver]

If I change Automatic Transmission fluid, do I still need to change the Front Differential fluid separately? I wonder if the Automatic Transmission actually sharing the fluid with the Front Differential (fluid flows through them).

[b0pIT]

Yes they are seperate. the dif takes 80-90 gear oil

[bluestu]

I had my transmission fluid drained and replaced recently at the Toyota Quick Service, and I asked two service guys if I needed to have the differential fluid changed, and they said that it all flowed together. They also said that there was no transmission filter. Is all of this true or have I once again been misinformed?

[autodriver]

I had my transmission fluid drained and replaced recently at the Toyota Quick Service, and I asked two service guys if I needed to have the differential fluid changed, and they said that it all flowed together. They also said that there was no transmission filter. Is all of this true or have I once again been misinformed?

I crawled under my RX300. I found there are seperate drain plugs for Transmission, front Differential, and Transfer Case.

Automatic Transmission fluid filled from the ATF dip stick.

I saw a drain plug for front Differential.

I cannot find the drain plug for Transfer Case.

Whick "Toyota Quick Service" did you use?

[autodriver]

I called 2 Lexus dealers about 2001 Lexus RX300 AT AWD. One told me that Transfer Case uses Type T-IV transmission fluid. One told me that Transfer Case uses GL-5 gear oil.

I called 3 Toyota dealers about 2001 Toyota Highlander AT AWD. Two of them told me that Transfer Case uses GL-5 gear oil. One of them told me that Transfer Case uses Type T-IV fluid.

I took my 2001 RX300 AT AWD to a Toyota dealer (which told me that Transfer Case should use GL-5 gear oil). When I picked up my vehicle, the service slip states

"Drained and filled both front and rear diff. fluids. 4 pints.

Transaxle and trans. has the same fluid"

Then I was charged only 4 unit of gear oil, $1.50 each unit.

(If I am not wrong, 1 quart = 2 pints)

Note: My 2001 Lexus RX300 Owner's Manuals says that both Transfer Case and Differential use 1 quart of GL-5 gear oil.

I am so confused.

[bluestu]

Toyota told me they could not perform a complete flush of the transmission if it used type T-IV fluid. They said they could not run that type of fluid through their flush machine. They told me to look at the top of the dip stick to see what fluid it called for. (It said: Type T-IV fluid, transfer case uses different fluid).

I also know that just draining the transmission fluid still leaves about half of the dirty fluid in the transmission. You need to have it flushed completely and replaced with T-IV fluid, otherwise the fluid will always be dirty. That dirt will destroy your transmission over time. A man who rebuilds transmissions told me to flush the transmission at least every 15-20k mi. and replace the filter if it has one.

I'm trying to find someone who knows exactly how to service the entire transmission of an RX300. You would think the dealership's service depts. would have it together better than they do.

[itmdtr]

The transfer case uses 80/90W gear oil. I know, I replaced a couple transmissions, transfer cases, and rear main seals.

The rear diff. uses 80/90W gear oil, transmission uses T/IV.

[autodriver]

The transfer case uses 80/90W gear oil. I know, I replaced a couple transmissions, transfer cases, and rear main seals.

The rear diff. uses 80/90W gear oil, transmission uses T/IV.

Mine is a 2001 RX 300 AWD Automatic Transmission.

Please correct me if I am wrong.

1. Front differential uses GL-5 80W90 gear oil

2. Rear differential uses GL-5 80W90 gear oil

3. Transfer case also uses GL-5 80W90 gear oil.

I cannot find the Filled Plug for the Transfer Case. Is it filled together with the Front Differential or separate?

[bluestu]

I talked with a mechanic who works strictly on Toyotas and he said just draining and and refilling the transmission is a waste of money because only a fraction of the fluid is actually replaced. He suggested totally flushing the transmission which he says cleans all the debris from the wire mesh filter inside the transmission. He said the transmission uses T/IV fluid and the gear box and differentials use the 80/90 gear oil. He recommended changing those also. He said you should flush the transmission at least every 30,000 mi. or whenever the fluid starts to look dirty. The fluid should appear pinkish in color when it is clean.

I think this an important subject that all car owners should be aware of!!! This is comparable to having the engine oil changed regularly.

[autodriver]

I talked with a mechanic who works strictly on Toyotas and he said just draining and and refilling the transmission is a waste of money because only a fraction of the fluid is actually replaced. He suggested totally flushing the transmission which he says cleans all the debris from the wire mesh filter inside the transmission. He said the transmission uses T/IV fluid and the gear box and differentials use the 80/90 gear oil. He recommended changing those also. He said you should flush the transmission at least every 30,000 mi. or whenever the fluid starts to look dirty. The fluid should appear pinkish in color when it is clean.

I think this an important subject that all car owners should be aware of!!! This is comparable to having the engine oil changed regularly.

"Just draining and refilling the transmission" is not a waste of money although you only change 1/4 to 1/3 of them. You can do it more frequently. If you are going to flush the transmission every 40K, you can do drain-and-refill every 10K. You don't have 100% clean fluid, and you don't have 100% dirty fluid either.

I am not sure if RX300's transmission has filter screen.

Yes, transmission uses T-IV fluid. Front and rear differential use GL-5 80W90 gear fluid. Do you know what type of fluid used in Transfer Case (if yours is AWD). Some said "GL-5", some said "T-IV" Can anyone tell?

[bluestu]

I've talked to quite a few expert mechanics that have told me that you need to completely flush the transmission when the fluid starts to turn brown. What if every time you had your engine oil changed, they just drained out a quart or two and filled it back up? You would always have dirty engine oil. Doesn't sound like good preventive maintenance to me.

I'm taking my RX next week to have all the fluids changed. I'll let you know what the mechanic says about the transfer case fluid. I think maybe the front differ

[bluestu]

I'm pretty sure the front differential and transfer case both use gear oil and share it. I can only see one drain plug. I have also been told by three or four mechanics that the transmission in an RX300 does have a screen inside for catching particles. I'll know for sure next week.

I plan on flushing my transmission every 15,000 miles. A new transmission for an RX is very expensive.

[sgriffith]

I just looked at the maintenance schedule from clublexus.com and according to it, the front differential on an RX300 uses T-IV fluid....should I assume this is incorrect? I have a 99, so did they change the fluid type since then? I know this might seem excessive, but would doing a "drain & fill" on the transmission fluid at every oil change (since it is only about $7.00 for 2 qts) do away with the need for flushing? My reason for asking is b/c I purchased my RX with 30K miles about 3 years ago, now looking at 70K and this hasn't ever been done since I purchased the car (I was an uninformed person in many ways prior to joining this forum!!). I have considered just making this a part of my service...since a "drain & fill" isn't too time consuming. It has been the opinion of others on this forum that a consistent 15K service like this would keep everything in good working order (yes, I do change my oil every 3K....not every 15K!!). Should I change my ways and just do a flush once a year?

[autodriver]

According to my 2001 RX300 Owner's Manual:

Transfer Case uses GL-5 gear oil, 0.9L or 1-quart

Differential uses GL-5 gear oil, 0.9L or 1-quart

It doesn't clear state the Front and Rear differential.

A Toyota dealer changed my Front and Rear Differential, using 2-quart of GL-5 80W90 gear oil. It also stated that Transaxle and Transfer Case use the same fluid. If I am not wrong, transaxle means transmission.

A Lexus dealer told me that Transfer Case uses Type T-IV fluid. He said, " ... Sometimes the Owner's Manual is confusing. ..."

http://www.autoworld.com/RX300.htm says, "... automatic transmission with integrated transfer case ..."

http://www.carsdirect.com/research/lexus/r...00/base/reviews also says, "... automatic transmission with integrated transfer case. ..."

They mean that transfer case should use Type T-IV, not gear oil.

However, another Lexus dealer told me that Transfer Case uses gear oil, not T-IV fluid.

Very, very confusing.

[bluestu]

The transmission uses T/VI fluid and the other components use gear oil. I bought both my RXs with around 60k miles on them. I'm sure the transmissions on neither one had ever been flushed because the fluid looked very dirty. I did a drain and fill on both of them at Toyota for $45 a pop. The fluid still looks dirty. The transmissions still funtion properly, but after discussing this issue with numerous people, I've decided to have the transmissions flushed on a regular basis. Costs around $100.

[autodriver]

Hello bluestu,

It makes more sense to flush the transmission for $130 (around 15 quarts T-IV) than drain-and-refill for $50 (around 4 quarts T-IV).

When you flush the transmission, don't forget to ask the Service if flushing the transmission, the transfer case also get flushed. This is truth only if transmission and transfer case share the same fluid. Note: You don't have transfer case if yours is not AWD.

[RX in NC]

I battled with Lexus in October/November last year over the unsatisfactory shifting and stalling characteristics of my wife's 2000 RX300 transmission at about 48,000 miles. I wound up getting a new (rebuilt) transmission installed by the Lexus dealer under warranty in mid-November. She's put about 19,000 miles on the vehicle since then, and she's reasonably happy with the vehicle now. I still feel that the transmission is poorly engineered and will never perform to my expectations of what a Lexus ride should be all about from a comfortable, smooth-shifting transmission standpoint. But I did copious amounts of research on Lexus/Toyota transmissions in various locations (including this site) and I've developed a set of transmission guidelines that I'll strictly adhere to as long as we own this vehicle:

1. Ensure that nothing but Toyota Type T-IV transmission fluid goes into your pan. Don't let anyone else put any other type of fluid in there regardless of how strongly they're attempting to hype their new "wonder product" to you. If you choose to use a Jiffy Lube or similar outfit to handle your fluid changes, bring your own bottles of T-IV fluid with you and watch the tech to ensure he uses it. And keep in mind that a Toyota dealership will change your transmission fluid for much less than your Lexus dealership will charge you.

2. Change your transmission fluid every 30,000 miles. Your RX owners manual tells you to NEVER change the fluid unless you drive under "severe conditions". Don't believe a word of this - transmission fluid breaks down over time and use, and with Toyota's known transmission performance weaknesses in these Lexus RX models, you MUST change your fluid on a 30K interval in order to give your transmission the best opportunity for long life.

3. Don't push your acceleration limits after initially starting the vehicle for the first time that day. Your engine, transmission, and fluids need to warm up to normal operating temperature in order to provide proper performance characteristics. It varies from vehicle to vehicle, but allow at least two to four miles of driving before you initiate any hard acceleration.

4. And finally, document and discuss any and all transmission performance quirks with your Lexus dealer on a regular basis. Be professional, be specific, be accurate, but be firm. If you can demonstrate significant shifting or performance problems with your transmission that you believe are out of the ordinary from what would be expected of a supposedly luxury SUV vehicle, your dealer may very well decide that their best course of action to satisfy your concerns is to put a new transmission in your vehicle. That's exactly what we got last November. But you have to do your part in proving your case.

[sgriffith]

Warning...stupid question ahead...

In reading through these posts, I am confused. I do my tranny fluid changes every 15K, and I do not have AWD. In looking through my maintenance schedule, I know I don't have a transfer case to change fluid in, but what about Front & Rear differential? And according to my service schedule, then the front differential fluid is T-IV. Is this correct? Thanks in advance.

[RX in NC]

The most trusted Lexus transmission mechanic I know (he has worked for our local Lexus dealership for about six years and just last week he dropped our transmission in order to replace our leaking rear oil seal under the widely-used Lexus "goodwill" customer warranty) tells me that the front differential runs Toyota Type T-IV fluid, just like your automatic transmission does. Both the transmission pan and the front differential are filled with Type T-IV through your transmission dipstick tube. All the fluid then runs together into both components.

This is not rocket science, folks. If you're not afraid to crawl under your vehicle and you own a 10 mm Allen wrench (which you can buy at Sears or any reputable hardware store), you can maintain both of these components yourself and therefore ensure that NOTHING ELSE besides Type T-IV fluid ever enters your transmission.

[sgriffith]

Thanks RX in NC.....I appreciate the reply. I couldn't agree more with you.... my 22 month old daughter could do this type of maintenance....I just wasn't for sure about the type of fluid.

[itmdtr]

OK.

1: The "front differential" is the transmission (it's called a transaxle for a reason)

it uses T/IV transmission fluid.

2: The transfer case is called a transfer assembly, it transfers power to the rear wheels only, you can not shift out of all-wheel drive. It uses 80/90 gear oil.

2a: The transaxle and transfer assembly do not "share" fluid, that would be bad.

3: The rear axle is just that, and it uses 80/90 gear oil.

(The transaxle does have two drain plugs, one in the pan and the other one on the bottom of the diff. part.) But you fill both through the transmission dipstick.

About 4 quarts on a drain and fill. The transmission doesn't use a filter, just a metal screen.

[bluestu]

itmdtr,

You are the man!!! You are absolutely correct with your information. I have talked to several expert mechanics and they told me the exact same thing. They also told me to totally flush the transmission every 30k or kiss it goodbye. A drain and fill is useless. That's why so many Lexus owners are complaining about transmission failure. Comparable to extending the life of the engine oil until it turns to sludge. Trust the experts or trust the dealerships???