Hey folks! I haven't posted on here in over a year. I'm currently having some concerns with my transmission and wanted some insight.


This is a 4x4 '03 with the A340F NON SEALED 4 speed with a dipstick.
Currently sitting at 212K miles.
Just did a full fluid exchange with 16 quarts of valvoline maxlife.

Previous context: I bought the vehicle with 193K on it. Transmission has never had any major issues, but it feels a bit tired. Shifts have always been a bit on the harder side of normal. Nothing bad, I can just tell the transmission has some miles on it. Its never really rolled forward much when put in gear either, it always needs to get throttle to go forward.

When I put 33's on, I could tell the shifts got a bit harder. Still normal, but a bit more tired than they were before. Makes sense, bigger tires put more strain on the entire suspension and drivetrain.

Last week I had a couple of odd shifts where it banged a bit from stopping at a light going into first. I changed all the fluid.

Now, it still feels a bit tired.


1) my dipstick currently shows fluid very slightly over the top hot mark when having driven for a while. Could my fluid be too high? Checked with the engine off, in a relatively level place.

2) How concerned should I be about this transmission?

I have a sealed transmission so I don't know for sure the proper method of checking the level on a T4R that has the dipstick.

But with most auto transmissions with a dipstick you need to check the fluid level with the engine at operating temperature and running and in park, on some older vehicles in drive with the parking brake applied, as said I'm not sure what it is on a T4R with a dipstick but I'm sure the engine needs to be running.

On all transmission dipsticks I have ever seen it's printed on the dipstick usually on the blade but could be on the handle exactly how to check the fluid level properly.

Since you check the level with the engine off which I'm pretty sure is incorrect it's very possible the level is way too low or too high, either is not good for it too operate properly, my guess is that it's most likely too low, but checking it properly is the only way to know for sure!

This is helpful, and confirmation of what I just found. I did some research on the A340F transmission (which was in the 1st gen tacomas, 3rd gen 4runners, and the 03/04 4th gens. Most of the fluid checking instructions specified engine running.


I just got it to operating temp and checked it with the engine running, and it was barely at the bottom of the lower hot mark. I added 8 oz of fluid and the shifts have already dramatically improved and smoothed out. Level was still almost at the same level after driving a bit, so I added 8 more oz, and will drive for a couple of days and check again.

It looks like my trans was underfilled.

You don't need to drive it for a few days to get the fluid temperature where it needs to be to check the level properly, drive it until the engine is up to normal operating temperature and then check it again and fill it to the full mark if necessary, driving it too long under filled is not good for the transmission and can do further damage to the clutch packs, if low add 4 ounces at a time then drive around the block, check it again, add more if needed once you get it up too the full mark then you can drive it a few days and check again but at that point unless you have a leak you should be good to go.

Same for every automatic transmission with dipstick I've ever seen including GM, Ford, Subaru, etc. Engine running at idle, transmission at operating temp, vehicle level.

Also, MaxLife fluid's hot viscosity is on the low end of the spectrum for your transmission. Yours calls for T-IV fluid which is thicker than WS...MaxLife claims to meet both specs. If you find you're not happy with the upshift or downshift behavior, consider exchanging for T-IV spec fluid.

The data below are gathered from manufacturer product data sheets, and show the significant difference in viscosity between MaxLife and Castrol's product which meets T-IV spec but not WS:

Product 40degC visc / 100degC visc / Viscosity Index
Valvoline MaxLife 28.82 / 5.91 / VI 156
Castrol TransMax Import Multi-Vehicle 36.6 / 8.0 / VI 200

Update-followed directions above and added a bit at a time. I’m now reading in the middle of the hot range at normal operating temp. I ended up adding 24 oz. it’s shifting great, feels smooth and tight now like it’s supposed to. Feels actually better than it did before I changed the fluid out.

Also great to know about viscosity of the maxlife! Going to keep a close eye on that going forward. Thanks


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Good to hear it working as it should now!

If it was shifting hard and or slow before you changed the fluid I suspect it was low on fluid, I would check the level again in a week or so just to make sure the fluid level is staying where it was then maybe once a month or two until you feel good about it staying at the proper level and also check underneath in the next few weeks just to make sure you have no visible leaks showing up on the bottom of the pan and or ground, transmissions don't use or burn fluid/oil like a engine can sometimes do if they get low it's usually from leaking.

If you do notice the pan wet with fluid/oil, smell it and look at the color, engine oil and transmission fluid have a different smell and color and you should be able to tell the difference as too which it is, any engine oil that maybe leaking can easily be blown back and down to get to the transmission.