I have a confession to make (re trans/t-case fluids)

[Arya Ebrahimi]

In the 60k+ miles I've owned my 80, I have never changed the Trans or T-case fluids. (Diffs and engine oil are serviced regularly) I'm not even sure what the proper procedure is for checking the fluid level let alone changing the fluid, and I have no idea when they were done before I got the truck. Now the truck shifts fine, and nothing makes any noise, but I feel really guilty about this.

I've been told in the past that changing the ATF in a tranny that has not seen fresh fluid in a long time is nearly instant suicide for the transmission. It was explained to me that the bands in the transmission break down in the old fluid and the friction material accumulates in the fluid. This allows the trans to continue functioning properly, but once you change the fluid, this material is removed and the trans will start to slip.

What do you guys think? Does this apply to the 80 trans? Should I proceed to change my fluid or just run it till she dies? The truck now has 203k miles on it. I will be getting a new DD in May and then the 80 will be relegated to weekend camping rig/trail duty and will most likely see a drivetrain swap for something a little more exciting/powerful.

Thanks,

Ary

 

[Lka1988]

I've been told in the past that changing the ATF in a tranny that has not seen fresh fluid in a long time is nearly instant suicide for the transmission. It was explained to me that the bands in the transmission break down in the old fluid and the friction material accumulates in the fluid. This allows the trans to continue functioning properly, but once you change the fluid, this material is removed and the trans will start to slip.

This has been explained to me as well....except I haven't had mine changed for a VERY long time...

 

[Jacques Villeneuve]

I've heard the same story and come to think of it, I've had three tranny failures in various vehicles (92 Suburban, 95 Pathfinder and 97 ML320) all just after (~ 5000 miles) having the tranny fluid and filter changed.

Go figure.

I've read where a product called "Transmatic" works wonders (read this on a Lexus RX website).

http://www.transmaticsc.com/

 

[-Spike-]

By that theory it doesn't matter if you change it or not- supposedly the friction material is wearing off, and every time you change the fluid you lose it. Sounds pretty hokey to me.

-Spike

 

[Romer]

I had mine changed about 40,000 miles ago. No problems.

 

[Arya Ebrahimi]

Well I went and read up in the owner's manual, and I checked it according to their directions and mine seems to be fine. It's still nice and red and does not smell burnt. Guess I'm ok for now then. It does leave a little bit of a black residue on the paper towel when you wipe down the dipstick, but the fluid is not black and definately turns the paper towel a pinkish color.

-Spike-, my understanding is that the bands only break down when the ATF has degraded to the point that it no longer lubricates sufficiently, thus allowing the bands to "wear". With clean fresh ATF this shouldn't be a problem and the bands should last indefinitely. This is of course all just crap I read on the internet, so who knows if it's true or not.

Ary

 

[Lka1988]

Well I went and read up in the owner's manual, and I checked it according to their directions and mine seems to be fine. It's still nice and red and does not smell burnt. Guess I'm ok for now then. It does leave a little bit of a black residue on the paper towel when you wipe down the dipstick, but the fluid is not black and definately turns the paper towel a pinkish color.

You're lucky. I just checked mine, it's orange...and smells burnt. But it works fine, so I guess the old saying applies, "If it ain't broke, don't fix it"?

 

[Arya Ebrahimi]

Yeah, I'm a bit baffled actually. I drive the crap out of my truck, and have towed 4-6k lbs numerous times in the past 60k miles(usually a loaded car hauler). I know I'm not easy on my truck, and it shows to an extent, but for the trans fluid to be this clean is amazing IMO.

 

[ArmyFJ]

Ahh....the logical fallacy, "After this therefore because of this"
Change the fluid. If it fails shortly afterward, it was probably due to fail from other reasons than giving it new fluid. Plus you get to learn how to rebuild a tranny.

Matthew

 

[ArmyFJ]

You're lucky. I just checked mine, it's orange...and smells burnt. But it works fine, so I guess the old saying applies, "If it ain't broke, don't fix it"?

Its called preventive maintenance so that it doesn't break...and when you would have had to fix it...you already did (or just put $20.00 worth of fluid in.)

Not that I might have done the same thing before....

Matthew

 

[C6H12O6]

"Red" fluid doesn't necessarily mean it's good. Mine looked red on the dipstick. Pretty dark red when I changed it. The new ATF barely shows up on the dipstick it's so clean. New, fresh fluid looks nearly clear with a hint of pink on the dipstick.

 

[Cruiserdrew]

Yeah-Just change it already. When you do a drain and fillof ATf, 4 quarts comes out. That's about 1/3 or so of the capacity. Do this at each oil change for the next year or so, and the fluid will get changed out gently and easily.

The t-case is a no brainer. There is less than 2 quarts of fluid there. 100% of the drive load goes through it constantly. Change it like religion. I swap it once per year with Mobil1 75w-90.

Not changing fluids is like burying your head in the sand and waiting for armageddon.

 

[Mike Ohler]

Tranny Fluid

I have also been negligent with the tranny fluid in my vehicles after an incident with my 92 chevy 1500. Shortly after replacing the fluid in the chevy transmission it went out and I had to install a replacement transmission. I just bought a Cruiser and would like to change the tranny fluid, but am apprehensive. A co-worker suggested just removing and adding a couple of quarts of transmission fluid with each oil change. This seems like a good idea, as some new solvents will be added regularly. Hopefully this will not shock the seals and other magical stuff.

 

[C6H12O6]

Would you guys slowly change motor oil over a year? Get the old stuff out of there and put fresh, new fluid in. Follow the procedure outlined in the FAQ. Takes about a half hour and your truck will shift like new. If you're worried about seals, look at one of the higher mileage ATFs out there.

 

[Bruneti]

Generally speaking, transmission fluid is a lubricant with a detergent package to keep the internal parts of the transmission clean. If some of the fluid is not drained and replaced on a periodic basis, the detergent additives will be used up and not continue doing their job. Then, varnish & residue builds up on the parts of the transmission. Doing a quick series of drain & fills, or a complete fluid swap, will very quickly replace these detergent additives and begin loosening a lot of what has built up in the tranny. All this released buildup will then be captured by the trans filter of most vehicles. If the fluid has gone neglected long enough, it can possibly release enough to plug the trans filter which will starve the transmission of lubricant, and obviously leads to transmission failure. Mr. T uses a screen in the transmission of your 80 instead of a fine filter, which avoids the filter plugging issue. A 4 qt.drain and fill regimen after every couple oil changes will replace the fluid more slowly and is probably still the safest for a neglected trans. That said, many have done full fluid swaps to baseline their tranny fluid with good success.

 

[Bryan062087]

If you aren't having any problems with the ATF and its clean and not burned. I would say you don't really need to change it. Same thing with x-fer case oil.

245k miles on original ATF/transfer case oil in our 80.

275k miles on original ATF/transfer case oil in my dad's old 62. (sold now)

No problems with either.

I've changed the AT fluid in my 62 multiple times, but have had to because of overheating etc.

People on this board tend to be maintenance crazy.

 

[C6H12O6]

I would say you don't really need to change it. Same thing with x-fer case oil...

245k miles on original ATF/transfer case oil in our 80.

275k miles on original ATF/transfer case oil in my dad's old 62. (sold now)

People on this board tend to be maintenance crazy.

This is quite possible the dumbest advice I have ever read on 'Mud.

I agree that some of the people here are a little anal, but advising somebody to go 275K+ miles on vital drivetrain fluids is absolute madness.

 

[-Spike-]

This is quite possible the dumbest advice I have ever read on 'Mud.

x2

-Spike

 

[hadji_85]

This is quite possible the dumbest advice I have ever read on 'Mud.

I agree that some of the people here are a little anal, but advising somebody to go 275K+ miles on vital drivetrain fluids is absolute madness.

The manual for my Isuzu Rodeo says the transmission fluid doesn't need to be changed unless you are constantly towing heavy loads. I've also heard the same thing about change trans fluid on a trans that hasn't had fluid changed in a while.

 

[IdahoDoug]

Bruneti's said it perfectly. Drain and fill on a 93/94 yields something like 6 quarts, vs less on the 95+ models with their girlie transmissions. Arya, change the TC fluid out completely and do a drain/fill on the tranny with regular tranny fluid and you'll be helping it out immensely. Repeat the tranny drain/fill change annually if you're going to be tough on the truck. Get one of those long funnels to fit the tube of your dipstick 'cause that's where the fluid goes back in and not having one is among the great frustrations of life when you're refilling.

Whatever you do, do NOT let anyone completely change the tranny fluid out with a flush machine for the exact reasons Bruneti mentions. After you've done a drain/fill and 6 months have elapsed, you could bring it in to a Toyota dealer to have the pan dropped, screen cleaned and more of the fluid changed out due to the pan dropping. But STILL - do not let them do a tranny flush, or any kind of cleaning fluid strategem. Just fresh fluid, thank you very much...

DougM