I have asked around many different transmission shops, mechanics, online research, etc with conflicting answers on this issue- specifically on a 2005 RX330 2wd (which takes T4 ATF)- First, can synthetic and conventional ATF's be mixed in this transmission? The conventional being Aisin T-4 and synthetic Valvoline Maxlife ('T-4 compatible'). Can I do a drain and fill with the Maxlife when there is already dirty conventional T-4 in there?

Also, what transmission hesitation/slip fix additives can be successfully used in conjunction with Aisin T-4, synthetic Maxlife, or a mix of those two ATF's?
For example, can I mix Lucas 'slip fix' with these two ATF's? If not, then what hesitation/jerk/slip 'fix' product IS compatible with these ATF's?

I have drained and refilled (diluted) 3 times over the past few months. 5 qts each time. Most recently was to dilute out the synthetic Maxlife. I didn't want to run into any potential problems with that down the road, being that it is not actual T-4... So I have been adding back in Aisin T-4. I think all the draining has now caused my tranny to start hesitating/hard shifting. Also hard to go over 60mph, and bit of a struggle at the top of hills.. wanted to see if any chemically-compatible 'fixes' that arent gimmicks might possibly work. (tranny started shifting a little worse the last time I replaced 5 qts with Aisin T-4.. might be a bit too thin of fluid for an Rx330 with 145,000 miles? Overall fluid level is on point.) thanks

 

I've mixed many fluid brands never had a problem but of course always use what is spec'd for the particular application. I personally think Maxlife is the most overrated ATF out there I've tried it a few times and quickly concluded it's no good, money spent and lesson learned. Many swear by the stuff.

You can use Lucas is just about any auto transmission, it is quite good and compensating for worn clutch packs other problems it likely won't help. I used to like Royal Purple ATF it works great when new but breaks down quickly so I dumped it, only use Amsoil now. For T-IV I use Amsoil OE Multi-Vehicle, their signature series it better suited for WS from what I've read. Signature series in Dexron and T-IV applications doesn't seem like a good match.

 

Are you throwing any check engine codes and running in limp mode?

Only ask that beacuse of your other threads about the broken wheel speed/abs sensor and other stuff.

Just making sure because I don't think it won't go into over drive when in limp mode but that's different from transmission slipping as you know- just checking.

 

I've been using Amsoil 100% synthetic ATF fluid, Amsoil products are the best on the market, I have done a lot of research on the subject of engine, ATF and diff fluids

 

Front driver side abs speed sensor is still out, and its tripped up the brake light switch sensor and some other abs code, as well as both rear abs speed sensors (unless those are actually burnt out too..). Aamco guy said its causing the torque converter to do something weird because the computer thinks the car is flipping overor something. i cant get the front sensor part in for a couple more days. Its hesitating and jerking/hard shifting into most gears.. Sounds like whining a bit from the torque converter area possibly,
It has indeed started shifting a bit worse after i drained the pain for the second and third time (both times were after the sensor and codes were already tripped..)
Aamco said there are no transmission codes just that abs and speed sensor, tripped up brake light switch issue.. Brake lights do still work so..

 

When I was in limp mode my car ran and drove terrible, just throwing that out there as what if...

 

I'd add that you should change out the trans filter as that also gives you a chance of cleaning the pan as well as the two magnets.......

 

aamco won't service the filter until I get the speed sensor(s) issue under control, and I'm waiting for that part to come in. I have the filter and gasket for the pan but I really would rather pay to have them do it than me..
It could be in limp mode? The ABS,TRAC OFF, VSC, and tps blinking image are on from the sensor being out. I have the codes written down somewhere but basically 3 abs speed sensors, the stop light switch, and another abs code are what has been scanning. no other codes yet. I know at least the last 2, if not all other 4 of those codes are being tripped by just the driver side one.
2-4 Wheel bearings, front lower ball joints, back struts, back rotors, PS line, and a heat cracked dash are other problems that should/need to be dealt with.. can't believe nobody before got the dash recall done!

So if after the sensor and filter are replaced and the transmission still shifts hard, am I safe to say I should get rid of this and get a toyota?
Or is it worth putting in a new transmission along with all the other things? I would be paying a mechanic for pressing work and new transmission if necessary..

 

Exactly, no prefessional transmission shop will do a tranny service on a car that acting like it may need a transmission rebuild.

There may not be anything wrong with your transmission and that's why AAMCO wants you to get those codes fixed first and see
how it goes and if the tranny is working good at time they may offer to do the tranny service.

They will not do a tranny service if they think the tranny is slipping.

I have been diggin in the repair manual and can't find the info on limp mode.

 

Man thanks for all your help and same with everyone!
if the transmission is okay, could the lucas fix actually cause any damage?

 

If I need a new transmission should I go with a rebuilt, used, or new transmission (if i can even find a reasonably priced one?)

I saw this video and it made me wonder--https://m.youtube.com/watch?v=a-Lkua0jKRE
Or should I get the valve body replaced along with new solenoids? Can this be done through the pan?
If the clutch packs or gears or TC are also worn problem(s) I suppose it may be better to just replace the whole transmission..

 

The tightest tolerance is the solenoids similar to a hydraulic lifters & any debris in the fluid will cause the solenoids to stick, delay shifts, ect which plays havoc on clutch packs, ect......As far as trans swaps, I've had to replace a 4R100 trans in one of my trucks, & for my wife's car yrs ago, I had the original rebuilt & on another car I sold it w/ swapping the trans. I'd have the original one rebuilt w/ a new torque converter as well as a new trans cooler or have the shop flush out the cooler real good. Shop around, hitup 3-5 shops to see what they say as that tell you which way to go as far as replacing the vehicle or redoing the trans. Best of Luck, keep us in the loop........