Change to synthetic ATF in differential??

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bcossa2001

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My 97 Avalon (148K miles) specs Dexron III in both the trans and the differential.

The differential holds a whopping 1.7 quarts. Does anyone think it would be a mistake to try synthetic ATF? Is there any obvious benefit?

I have had no problems with either the trans or the differential--just wondering what the opinions would be.

Thanks....
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A synthetic ATF would reduce heat and wear, so yes, I'd say it would be worthwhile changing it. Everyone reports faster and smoother shifts with AMSOIL ATF. Also, I've had many people report highway RPMs on the tach reduced meaning less slippage. Less slippage reduces heat and improves mileage.
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I changed the differential fluid in a twenty year old rwd Cadillac with 125k miles. Original fluid, and it flowed! Not virgin by any means, but at least I got it out of there. There had been a bearing whine just starting to develop.
1.7 quarts of Redline differential fluid (synthetic)75w90 as spec required and I'm three years and 40k later without a drip or whine.
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I'd use Schaeffer's synthetic ATF in that application in a heartbeat if it called for a DexIII equivalent.
Let us know what you did!
 
If you've never changed the diff, I'd consider a rinse run with ANY dexronIII prior to switching the diff to synthetic. I recommend a 500 mile rinse because of the amount of junk/crud that can build up that you'd want to remove prior to adding new fluid and driving another 150k without doing anything.
Toyota isn't too accurate with the front diff fill amounts. If you are on a level lift, don't be surprised if it takes more.
If the diff is the factory fill, it might look pretty scary coming out. The same can be said about the ATF in the tranny too.

The cost/benefit of the synthetic is for you to decide. I myself want the best and always use a full synthetic everywhere possible. For a fluid that you might not ever be changed again, I would definitely consider it if in budget. If you're on a budget, MerconV and other multivehicle blended synth ATFs, are cost effective and work extremely well.
 
I've owned a 97 Avalon. The diffential in those cars gets filled when you fill the transmission with fluid. I've always used Toyota ATF but after discovering BITOG would have converted to Amsoil ATF if I still owned the vehicle. The Avalon transmission usually shifts extremely smooth, in Lexus like fashion with an old Dexron III. Do go ahead and switch to Amsoil ATF if you are due for transmission service. It is fully compatible and may provide some benefits of the synthetic fluid.

On another note. I've owned by 97 Avalon since new and have kept it on a 5w-30 diet of GTX with a 3k OCI. The car was totaled last year with 98k on the odo. I never got the chance to pen up the valve cover to see the condition of the engine with 3k OCI as I've heard they are very sludge prone. How many miles are on your Avalon, what oil do you use, what OCI, and how is the condition of your engine overall? Sorry if I've pushed this thread a little off topic.
 
I've also forgot to mention that if you just pour the amsoil atf into the differential it will get mixed in with whatever dexron III you have in the transmission right now as this car does not have a seperate diffential compartment and shares fluid with the transmission. Check your build date and dealer/mechanic to make sure.
 
The car has 143K miles on it now. I've owned it since day 1 and the OCI has been 3k. I used to use fram oil filters until I started reading BITOG--now I use either Wix or Purolator.

I started commuting 150 miles per day in June of 06 so I have pushed the OCI to 6K. I usually use Havoline 5W-30, although I think I may change to a high-mileage type oil.

Car steadily gets 30 MPG. This year/model is supposed to be sludge prone so I put in Autorx about 1200 miles ago--I am going to change the oil this weekend for the rinse phase. I have not noticed any adverse effects from the initial cleaning phase (I have read posts where drivers were hearing strange noises, etc.). No change in gas mileage either. I dumped some Techron in about 2 tankfuls ago and can tell a difference in the acceleration--smoother than before.

The Haynes manual says that the diff is separate from the ATF--there are 2 drain plugs and I have kept it changed every 30K and am certain that there are 2 different sumps.

I have not had any engine trouble nor trans trouble. Replaced the water pump twice when the timing belt was changed, replaced the power steering pump, and the drive boots on each axle have gotten torn and had to be replaced. I'm very pleased with the vehicle.
I previously owned a Honda Accord that went 180K before burning a quart of oil a week. Also owned an 84 Pontiac Grand Am that went 185k and then burned a quart about every 2 days. Seems like I can't get past the 200K benchmark.
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Thanks. I looked at a quart of the Mobil 1 synthetic today at AAP and it does not specifically list that it can be used in Dexron III trannys. Does anyone know if it is ok????
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Front Wheel Drive with transmission and ring and pinion in one unit?

If it is an automatic transmission, I would say NO! the frictions are use to the Dino ATF.

If it is a manual transmission I would say YES!

These answers will cause some debate
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but, that's what this forum is all about
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Quote:

Front Wheel Drive with transmission and ring and pinion in one unit?

If it is an automatic transmission, I would say NO! the frictions are use to the Dino ATF.

If it is a manual transmission I would say YES!

These answers will cause some debate
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but, that's what this forum is all about
fruit.gif


Click to expand...


Are there 2 fill plugs?

Quote from U:

The Haynes manual says that the diff is separate from the ATF--there are 2 drain plugs and I have kept it changed every 30K and am certain that there are 2 different sumps.
 
Yep, many toyota automatics have separate front diff drain/fill plugs, usually taking ATF and not gear oil.
It varies among the powertrain and years.

The Haynes book will include powertrain inaccurracies. The drain/refill plug are easy to find on the firewall side of the tranny. The diff is covered in cooling fins. The plugs are on the top/bottom of the fins. Refill until ATF overflows the fill plug while on vehicle is on level surface. It could take more then the published capacity.
 
10-4. The differential is filled through the hole on the side. The tranny is filled from the top through the dipstick tube.

Thanks to all....
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Mobil 1 ATF is Dexron III approved. The Avalon & V-6 Camry BOTH have separate differential & transmission sumps. Both have drain plugs and BOTH A/T & diff. call for Dexron III ATF, or they did in 1996.
Those transmissions shift like a hot knife through butter. I've used Mobil 1 for well over 150,000 of the 200,000 miles in my Camry V-6 & maintain it with pan drains every 20,000 miles. I plan to drive the old car another 200,000 miles and really feel like the A/T, thus maintained with the Mobil 1 ATF will 'go the distance.'
I do not dispute other synthetic ATF's are just as good... but with the performance I'm getting with the M-1, I'm not about to switch brands.
I also use Mobil 1 engine oil and Toyota filters, and have since the car was new.
 
Well since I was unsure how much of the old fluid could be drained out I bought Royal Purple at Napa. I was afraid if I bought something online I might not have enough.

Bought 3 quarts of royal purple. I was only able to drain out 1 quart of fluid at a time. I don't know how to flush a diffential (there is only the drain plug and the fill plug), so I did 2 drain and refills.

I'll check gas mileage next week and see how I do.

Also installed magnefine filter today. It was a snap....
 
No change in gas mileage...also can't tell any difference in the way the car drives....

I also learned, once again, that you should read your owner's manual. The Haynes manual said 1.7 qts in the differential. The owner's manual said .9 quart, which would explain why I was only able to drain out 1 quart.

After having read many of the posts in the tranny section of BITOG, it seems reasonable to me to believe that trannies have hard lives....mine in particular because I live in a very hilly area. I think changing to a synthetic is a good idea and I will change at the end of the current 30,000 mile interval.....

Trying these new things on the car is interesting
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