2003 LX470--transmission fluid never changed (1 Viewer)

[unkltrp]

I thought it was time to check and change the transmission fluid as Ive own my '03 LX470 for 3 years. I spoke with my mechanic friend who was a Lexus mechanic who helped me track the maintenance history. It showed the prior owner declined to have the trans mission fluid changed each time it was recommended. He said its probably best NOT to change it now but Ive gotten differing opinions.

Has anyone had experience changing out trans fluid after 140k miles?

Any advice would be very much appreciated. Thanks
Bill

 

[Mike NXP]

This is debate that has been going on between mechanics for a long time. Do you have a dipstick on the 03? If so check the fluid and see if it's burnt or not. Does it run good now or are you having issues with the transmission?

Some people are just old school / stubborn but my opinion is yes absolutely change it out. If something fails it was bound to happen anyway. 140k isn't all that bad. I've done complete flushes at Toyota every 30-40k since I've owned the truck and I'm at 230k miles now.

 

[SteveH]

Hydraulic fluid cools, lubricates, and carries away contaminants - just like engine oil. I would change it - maybe twice, waiting some time in between changes.

 

[ClassyJalopy]

Replace it - there is never a good idea to not replace it!

 

[Jerzywerzy5]

Just because it was declined at the dealer does not mean it was not done.

 

[unkltrp]

Just because it was declined at the dealer does not mean it was not done.

Thats a good point. Prior original owner appeared to get all of his maintenance done at the dealer but I dont know that for sure. Maybe I'll reach out to him and inquire. Thanks. I am now very inclined to fully replace the tranny fluid. Its not dark and doesnt smell burnt, so I must assume it was changed at some point. What do you guys think?
Thanks
Bill

 

[pvchaitanya]

Replace it - there is never a good idea to not replace it!

Be careful doing this! The safest way to play this is to take one quart or two quarts of fluid out and add equivalent new fluid and make sure its brought up to level by topping off additional fluid. And keep repeating this process every year or two so keep the rig running long.

 

[Zjohnsonua]

Your mech's advice is not unfounded. In some cases, old oil is carrying material that serves to enable functionality (ex: grit that helps worn clutches hold torque). Flushing all that out can remove that assistive material, leaving you with a problematic trans. However, this is not a hard rule - it depends greatly on what kind of life the trans in question had.

If it was mine, I'd drain and fill it a few times and carry on. As for what oil...if it calls for WS, use it. I used to scoff at the stuff thinking it was Toyota's money grab, but I can tell you the A750 behaves differently with it. No idea why though.

 

[katit]

Replace it - there is never a good idea to not replace it!

I agree. All of the "don't replace" advice coming because of 2 things:
1. Flushes. When machine used to flush tranny fluid under pressure - debris which is sitting in crevices might get freed up and plug passages/etc. So, don't do flush!
2. New fluid will have more "cleaning" additives and won't have clutch material dispersed in it. So it may cause slipping. As @Mike NXP said, if it's so bad - it will happen anyways.

I am for full replacement, but not flush. I disconnect at cooler and drain few quarts at a time and then replenish with clean. Use about 12qt total. Then, bring to temp and top off to level.

 

[excessive]

i changed mine at 149k miles (when i got my 2004) there was no history of it being done. The fluid was brown (thankfully not black ) and i noticed absolutely no difference in how it drives or shifts

 

[TheBussman]

change it. in the event it gets changed and stops working that means that the clutches are worn out and the only thing keeping it going before was debris in the fluid.

 

[Malleus]

It's simply not possible that contaminated transmission fluid will serve to prolong the life of a transmission. The contaminants in the fluid, at best, are the friction lining residue from use. This material cannot aid in clamping the friction and steel disks; it only gets in the way. Further, the loose material obstructs the tight tolerance clearances in the operating pistons and valve body, leading to further degraded operation.

At worst, the steels and seals inside the transmission can contribute to fluid contamination, and they are much worse for the operation than the friction lining material alone.

There is never a reason not the change transmission fluid, excepting only cost.

 

[TheBussman]

It's simply not possible that contaminated transmission fluid will serve to prolong the life of a transmission. The contaminants in the fluid, at best, are the friction lining residue from use. This material cannot aid in clamping the friction and steel disks; it only gets in the way. Further, the loose material obstructs the tight tolerance clearances in the operating pistons and valve body, leading to further degraded operation.

At worst, the steels and seals inside the transmission can contribute to fluid contamination, and they are much worse for the operation than the friction lining material alone.

There is never a reason not the change transmission fluid, excepting only cost.

I agree never a reason to not change the transmission fluid. However how to do explain it when a high mile trans has the fluid changed and then the transmission starts slipping/flaring or some times they wont even move out of the bay under their own power. I've seen it at least 10 times.

 

[Malleus]

A442F/A343F? Or transmissions in general?

 

[BullElk]

Wonder how many hundy trannys have failed due to not changing perfectly clean proper smelling fluid ?

 

[TheBussman]

A442F/A343F? Or transmissions in general?

transmission in general. many of them Toyotas

 

[Malleus]

No clue without opening them up. I would venture to guess that anything that happens as a result of changing fluid, would have happened anyway, under normal operation, since the pump that moves the fluid when it's changed its the same one recirculating fluid while operating. Assuming, of course, that the front pump method of changing the fluid was used. If a separate pressure pump was used, it may have overcome weak seals; operating pressure varies inside the transmission by design and a pressure pump won't do that. Simply draining the pan and refilling it wouldn't have any other than coincidental effect.