Transmission fluid change (1 Viewer)

[dnp]

I know this has been discussed before, but I'm not sure what was ever "decided" by the membership. Accordingly, I just want to get a few final opinions before I change my transmission fluid.

From the PO's records, it appears that the last trans oil change was in 2003 @ 54,000 miles. Now, with 111,000 miles on the clock, I'm thinking I should drain / fill (not flush) the tranny...On the other hand, I've heard folks talk about possible tranny problems following; therefore, is there any reason I shouldn't do this? (by the way, this is a Dextron III-filled trans)

I'd like to hear all opinions (either way)

Thanks

 

[Jim_Chow]

I'd flush. Drain & fill at 30K mi is okay, but you're at the 60K mi interval already. Here the So. AZ, the dealer does a drain & fill every 15K mi and full flush every 30K mi!

 

[calamaridog]

My mechanic does a drain and fill every 15k and never does a full flush...

 

[dnp]

My mechanic does a drain and fill every 15k and never does a full flush...

That's what I sort of feel more comfortable doing. I know it's not as thorough as a flush, but that may be exactly the point. It seems like I've read on this board before about people experiencing trouble(s) when doing a flush on a higher mileage 100 tranny, and I want to do the least "upsetting" move, while still trying to do something.. Now that I've established that I should use Dextron rather than Toyota fluid, I was just trying to make the correct next move.....thanks for the comments so far

 

[SWUtah]

That's what I sort of feel more comfortable doing. I know it's not as thorough as a flush, but that may be exactly the point. It seems like I've read on this board before about people experiencing trouble(s) when doing a flush on a higher mileage 100 tranny, and I want to do the least "upsetting" move, while still trying to do something.. Now that I've established that I should use Dextron rather than Toyota fluid, I was just trying to make the correct next move.....thanks for the comments so far

I did a "fluid exchange" with the latest Toyota transmission fluid on my 80 series at 90K miles (no problems at 130K miles). I am saying "fluid exchange" because "flush" implies that you are putting a cleaner in the transmission (which many places do when you go in for a "flush" and the cleaner is what will cause the failure). I just did the normal transmission service on my 100 series when I bought it at 58K miles since the fluid appeared to be very clean. If I were you and depending on how clean the fluid looks you could do either a normal service where they drop the pan and clean the screen and then refill or you could do the normal service and then ask them to do a complete fluid exchange using the newer Toyota transmission fluid. Whatever you do never let them put a "cleaner" in your transmission. A good way to check your fluid. Take a white sheet of paper towel and pull your dip stick, drip some transmission fluid on several places on the paper towel and let it dry. When it dries it should appear as pink spots on the paper towel. If it looks dirty or if it has a dark spot in the middle of the drop then I would do the fluid exchange. I got this information from a guy that is a consultant to the transmission industry. Hope this helps.

 

[LXPearl]

SWUtah, I agree. I have replaced fluid in an old Toyota trans before. I allowed it to run several thousand miles, then drained and replaced again (using Dextron III). The shifting improved and smoothed out nicely. The next change was at about 20K, then I went to 30 intervals. No cleaners. Trans fluid became pink as you indicated. Shifts were great. No problems.

 

[NMuzj100]

Just say No to any type of chemical flush or any exchange that uses high pressure. Drain and fill on a regular basis is probably the cheapest and best way to go. With the 100 you are draining 6 qts out of 17 qts so if you have burnt fluid then you need to do several drains and fills.

Link from 80s tech on a DIY full exchange. - This is proabably the best method if you are trying to move to a expensive synthetic fluid.

 

[SWUtah]

I went overboard on my 80. My neighbor had his own shop with a exchange machine. We dropped the pan and cleaned the screen. No sign of metal shavings so we filled it up and I drove it a couple of hundred miles but the fluid wasn't as pink as I wanted (not bad but not perfect) so we did the low pressure exchange using 20 quarts of the Toyota fluid (the extra fluid just moved more new fluid through the transmission, making sure the old stuff was out). After that it was very very clean. It still looked new 40K miles later when I sold the 80. I also "flushed" the power steering system and used a "cleaner" along with the replacement of the power steering fluid, with in 3K miles my power steering system was leaking (gasket seal leaks) I know it was the "cleaner" that caused that leak. Never, never, never let anyone use a cleaner in any system in your LC. I learned the hard way with that powersteering leak.

 

[calamaridog]

Just to clarify. My mechanic has a race shop where he builds desert racing trucks and he has a 3 bay Toyota Service shop. He hired the service guys away from the local Toyota dealers and they are all Toyota trained mechanics.

He services several UZJ100 platform trucks besides mine and they all have over 150k on them. He also services a ton of Tundras. Most of his customers beat the crap out of their trucks and run them hard.

He told me drain and fill only, every 15k. Since I don't know any better, I'm going to stick with his advice. So far he has not steered me wrong...

I would certainly welcome input from any mechanics who have a different opinion.

 

[SWUtah]

Just to clarify. My mechanic has a race shop where he builds desert racing trucks and he has a 3 bay Toyota Service shop. He hired the service guys away from the local Toyota dealers and they are all Toyota trained mechanics.

He services several UZJ100 platform trucks besides mine and they all have over 150k on them. He also services a ton of Tundras. Most of his customers beat the crap out of their trucks and run them hard.

He told me drain and fill only, every 15k. Since I don't know any better, I'm going to stick with his advice. So far he has not steered me wrong...

I would certainly welcome input from any mechanics who have a different opinion.

I'm not a mechanic but it makes sense that if you did a drain and fill every 15K you would be in great shape.

 

[ZJ2UZJ100]

Dexron III versus Toyota fluid

I did a (half a55ed) search for a thread comparing Toyota versus generic Dexron III ATF fluid to see arguments for/against either. Didn't find it. Anybody got a URL to the thread(s)?

More questions:


1) OK to use Coastal Dextron-III Mercon from PepBoys?


2) Can I do a drain and refill with Dexron III and run that for some miles while the OE Toyota brand is still in the torque converter? When they mix, are there any harmfull effects? How long can I run that way before I do another drain/fill with Dexron III? Looks like a couple thousand miles might be ok from posts above.

3) Rather than just open the drain bolt and then replace/refill, I would like to get a peek at the filter and pan bottom. I noticed the Transmission fluid dipstick tube is welded to the Tranny pan. And there are two brackets on the dipstick tube to hold it to the engine as it travels up to the engine bay. When I drop the Tranny pan, do I have to unbolt the dipstick neck supports in order to get to the screen and magnet(s) in the pan? Is there enough play in those brackets and the tube to tip the pan down?

Thanks for any help you offer.

 

[vcheng]

I would suggest Mobil1 Synthetic ATF if you want to use a Dexron III compatible fluid, or Mobil1 Type 3309 ATF for a Toyota T-IV compatible flluid.

 

[ZJ2UZJ100]

Thanks for the quick reply.

My date of manufacture printed on the door sticker is 3/00. It looks like the uncertainty about which fluid should be used is centered around the 2000 model year.

The Owner's Manual says use Dexron II or Dexron III. The folks in the thread below (yeah, I did some more earnest S'ing T.F.A.) seem to be split on whether to believe the manual or go for T-IV type fluid.


If I pick one of the Synthetics that meet DexronIII and T-IV, I still have the question about how long I can run with a mix of the new and old in the system. Does the rule of thumb about never mixing synthetic and non-synthetic oil still apply to ATF?

https://forum.ih8mud.com/showthread.php?t=22580&referrerid=4449

 

[SWUtah]

I would suggest Mobil1 Synthetic ATF if you want to use a Dexron III compatible fluid, or Mobil1 Type 3309 ATF for a Toyota T-IV compatible flluid.

That's what I used when I did the fluid exchange Mobil 1 synthetic. Best stuff you can buy

 

[SWUtah]

Thanks for the quick reply.

My date of manufacture printed on the door sticker is 3/00. It looks like the uncertainty about which fluid should be used is centered around the 2000 model year.

The Owner's Manual says use Dexron II or Dexron III. The folks in the thread below (yeah, I did some more earnest S'ing T.F.A.) seem to be split on whether to believe the manual or go for T-IV type fluid.


If I pick one of the Synthetics that meet DexronIII and T-IV, I still have the question about how long I can run with a mix of the new and old in the system. Does the rule of thumb about never mixing synthetic and non-synthetic oil still apply to ATF?

https://forum.ih8mud.com/showthread.php?t=22580&referrerid=4449

Just buy 20 quarts of Mobil 1 synthetic ATF and do a complete fluid exchange. That way you will know you have it all out and then you can run 60K miles before you need to do another service. I did this on my 1995 FZJ80 and it still looked new after 60K miles.

 

[NMuzj100]

The Owner's Manual says use Dexron II or Dexron III. The folks in the thread below (yeah, I did some more earnest S'ing T.F.A.) seem to be split on whether to believe the manual or go for T-IV type fluid.

Trust your Dipstick. If changes were made to the transmission they will have been reflected in the dipstick markings even if they didn't get to the owners manual.

If I pick one of the Synthetics that meet DexronIII and T-IV, I still have the question about how long I can run with a mix of the new and old in the system.

The more newer you have the better. But drain and fill will work over time. Mixing of old and new was planned for by Mr T. (6 qt drain and fill - 17 qt total fluid volume)

Does the rule of thumb about never mixing synthetic and non-synthetic oil still apply to ATF?

This isn't a rule of thumb. This is talk from someone who knows nothing but feels the need to give automotive advice.

The Synthetics will say compatible with non-synthetic fluids right on the bottle.

To really learn about ATF spend sometime reading at www.bobistheoilguy.com

 

[Jim_Chow]

Good point about insisting the shop do a low pressure fluid exchange. When I think of flush, I think of merely replacing all the old fluid w/ new fluid through one of those exchanger machines. A drain & fill every 15K mi should be ample. Or if you feel your fluid is old, do a drain & fill, drive around the block, repeat, drive around, repeat. Pretty soon, you'll have most of the old fluild replaced although you'll waste more fluid doing this.

I did a partial PS fluid transfer. A turkey baster was a tad large to get deep in there, so I used a piece of 1/4" clear pvc tubing and sucked it out like a straw. Old PS fluid (here in AZ) had this burned smell at 50K mi, left a stain on the side of the resevoir! I used some Valvoline dextron III/mercon ATF for older trannies (has additives to dissolve residue). Driving around for a few weeks seems to have removed the stains from the inside of the resevoir. After that, I have 1 qt remaining of Redline ATF...BTW, it is Dextron II...the only dextron II I've been able to buy.

Anyone have any opinions about mixing different brands of type IV ATF? If you use Toyota ATF, at least it should chemically be the same as what's in there now...might be the safest way if you only do a drain & fill and know Toyota ATF is in there.

 

[vcheng]

Don't worry about mixing any Mobil1 oil in your transmission, as long as it is the correct type.

 

[dnp]

I went the safe route and just drained / filled. Out of an abundance of caution (though I'm sure it wasn't necessary), I replaced the drained fluid with Toyota-brand Dexron.....I'll probably do this again in another few thousand miles.

Thanks for all of the advice....as most would agree, most couldn't afford to pay for all of the good advice found on this board!!!

 

[ZJ2UZJ100]

Thanks for the advice, folks.

Next wrenching session, I'll give it a go. Prolly buy 5 gallons of Mobil 1 ATF. Might as well keep their profit margins up while I own a few shares of their stock, right?


I'd still like to drop the pan and check the screen. Any comments on how much needs to be disconnected along the filler neck/dip tube in order to get at the screen? It looks like you need to take off both bolts that hold the filler neck upright to the engine bay in order to drop the whole pan.

If you dropped your pan, did you reuse the gasket or replace?


Have done a few drops/screen replace on Jeeps in the past. Filler tube was separate from the lower pan; much easier.