how long between ATF changes?? i am going to have a Sonnax put in and i dont know if this means that i have to cahnge the ATF or not but i may while i'm at it. i dont know what type of atf the prev. owner was running but the truck was his baby so i am sure it was something good. but if i did drain the fluid and add mine, if a little bit of the 2 types mixed (as long as what he was using was good) would it really matter?? also does anybody know if it all needs to be changed when a Sonnax goes in??

i know that the rebuilt tranny was put in about 20k miles ago so surely the fluid is no more than 20k miles old - so how is that?
thanks guys

 

Well, you'll have to drain the tranny pan to install the sonnax...it makes sense to me to drain the entire system and replace the fluid. There is no way that I would drain the fluid to service the innards and then replace the same fluid when finished. I take no chances with this tranny...external cooler, external filtration (both spin-on and Magnefine filtration) and external drain to make fluid changes a bit easier. I change fluid every 20k miles...

 

so when i put in the Sonnax, just drain the fluid and replace it - i was not going try to re-use the old fluid but i did not know if at all needed to be changed when Sonnax went in. - how much fluid for whole system 1,000 quarts or so ??

 

You could do it as you describe (drain pan, pull pan, install sonnax) then reinstall pan and refill to proper level. I would drain torque converter while I was at it, replace the pan filter, then the refill will be about 17 quarts. I can't tell you what the pan holds exactly...I have never drained just the pan...I change all of it at one time. Another thing, the change interval for the fluid is 30k.

 

how do you drain the tc?? and does it take the same fluid ?? also do i just fill to the top or how do i know?? if i get the pan filter, what am i looking for to get at store
thanks

 

i think you should be patient and wait a little for responses. we all aren't on here all the time to answer questions right away. you will get your answer eventually. first a PM, then a thread posted once you didnt get a response (i was at work) and now another thread posted 9 minutes after this last post of yours asking the same thing. patience is a virtue.

 

The TC probably has a drain plug in it (some years don't I guess...someone know what years?)...Get a friend to bump the starter a few times to bring it to the bottom so you can put a wrench to it. Have a BIG pan under it before you remove the TC plug. Drain all of the atf out. Pull the tranny pan (slowly) and drain all of the atf out. Do the sonnax install and install the new tranny filter (I can't tell which one to get at the auto store...they can by make/model and whether it is 4WD or 2WD - I have a 4wd and the part number is: Ford Part #F6TZ7A098BB or Purolator Part# 1214).

Install the 20? tranny pan bolts and torque them correctly (I can't remember what the torque spec for them is...I have a Mag-Hytec pan which uses allen screws and torque is 12-16 ft-lbs). Then you put the new Mercon fluid in through the auto transmission dipstick tube...get a funnel with a long neck for this! I would measure what you took out (in quarts) and put in maybe a quart less. Start truck up, let it idle, and move selector through the gears a few times. The TC will refill itself. Just let it warm up and after it is warm check level with the dipstick and add atf fluid until it is between the low mark and the full mark. Then drive the truck and get the fluid hot and recheck and top off as required - BUT DO NOT OVERFILL UNDER ANY CONDITION.

Now this is from memory and I do not use this approach myself on my truck (due to external filtration and drain capabilities)...but I have done it this way on many other vehicles I have owned. If you were not doing the sonnax install, I would point you to a much easier way to just change atf fluid...good luck!

 

You are going to be impressed by the amount of difference with the sonnax. For me, I am running dino ATF, I will be changing mine every 2 years or 20K which ever comes first. Most time it will be probably be based on the two year mark. The ATF is cheap insurance in comparision to cost of rebuild/replacement.

 

Any particular reason? Experience tells me otherwise.

Just curious....

 

but why drain the TC?? when you drain the tranny, dont you drain the TC??
i thought i would just drain the tranny, put the Sonnax in, replace the filter, and fill up the tranny and wouldn't that fill the TC also?

 

No, that will not drain the torque converter.

The trans will fill the torque converter.

 

NEVER overfill an automatic!!!!!!!!!!!!

If the fluid level is too high the rotating parts will be immersed in the fluid. As they rotate they will whip the fluid into a foam. Foam won't lubricate, so you will get A LOT more wear, plus the foam is greatley expanded from normal fluid, so it will be forced out of the vent, dipstick, and some of the seals. You can lose a couple quarts this way and be underfilled once it cools off.

 

once again, patience my friend...

you send me a PM about this at 7:44, and then post this same thing again at 8:00. tell me why i should answer your PM's.

 

I'll take your word for it....on the Ford. I have starved a pump and lost a transmission due to inertia. The builders for my other "Automotive hobby" have a fix for it and it is one additional quart AND a baffled pan.

 

Is this the factory recommended interval? I don't have my book at hand but do not believe it is that frequent. If I find out differently, I will get back, but that sounds awful frequent unless you are operating under severe conditions or just a maintenance freak. Then again, there's quite a few of those here, I just may be one of them but not with my tranny thus far.