First post and it’s a doozy!

OK , A full flush is not really the direction I would have started with in an attempt to fix this but you are at the point where you beleive the fluid is clean now .
Your transmission pump had to work very hard to get the truck to move while it was low on fluid . I am wondering how much debris the pump sucked up from the bottom of the pan and forced through the valve body when the truck was reversed with low fluid ? There is always debris in the bottom of the pan stuck to the magnets . In a low fluid condition ,a transmission pump with low mileage has enough power to pull debris directly off the magnets

Before we jump to the above conclusion , lets get some answers cleared up in order to diagnose this properly




EDIT : just read now he did a pan drain first . This will eliminate the pump from sucking any debris off the magnets



Were you able to clear these codes and double checked your fluid level ?
If the codes pop back up after you clear them , you have to dig a bit deeper to fix the problem now . Pan will have to come off

It was very low on fluid when she backed up the truck
When using reverse in an auto tranny , reverse needs the most line pressure . I beleive at least 160 PSI for the A750F transmission
If the transmission lost pressure because the transmission pump was starving for fluid , its going to explain the first code PO746 .

PO771 in your case was caused by the transmission slipping because the fluid was low

http://www.customtacos.com/tech.old...06toyrm/06toypdf/06rmsrc/rm2006ta/0280021.pdf

Can you confirm that your fluid level is topped off ?
Once the fluid level is confirmed as being full , double check to make sure the above codes are cleared . I hope your scanner has the ability to clear the codes .
If the codes have not cleared and are still present after a test drive , the truck is going to shift hard and you will not get overdrive . These are fail safes that are built into the transmission software to prevent further damage to the transmission .

 

And threads like this can be difficult to diagnose over a keyboard without test driving the truck lol
Keyboard warrior to the rescue hehehehe

 

Did you just scan the codes or clear them? If you didn’t clear them the system isn’t reset. Clearing them will reset it

 

Great point !!

The OP is new to the scanner game .
Fairly certain judging by his posts, all he needs to do is clear the codes and take it for a road test

 

Agreed. Road test AFTER confirmation of correct fluid level, yes? I think the only true issue is the fluid is still way low.

 

I vote for manual transmission swap. Then you'll never face this problem again

 

I’m definitely new to the scanner game! Here’s what I did... after the tranny flush I hooked up the scanner and that’s when I got those two codes. I then went to the option to “erase codes” and hit that option and I got this message “Erase codes command sent. Perform read codes function to verify.” I went back to “read codes” and they were now pending. So that’s when I took it for a drive and over the course of the drive the harsh down shifting went away but still no OD.

This morning I hooked up the scanner again and had p0776 (pending) code and not the p0771 code. So I erased that one and now I’m getting this message, “No codes are stored in the module!”

Fluid level is spot on, I cycled through 12.5 quarts just to be sure to get out any burnt fluid. I again used Fortech’s method of getting the truck in the proper temp range with no issues. I drained out close to a quart. I’m going to recheck it again in bit to be certain.

 

I have faith you will eventually fix this.

 

Got the truck in the AT TEMP range and checked the fluid, I got less of a trickle than I did yesterday. So I decided to add half a quart and recheck. I let exactly 8 of the 16 ounces drain out to a steady trickle.

Took for a drive and all seemed fine until about 3 miles in and I got an erratic down shift from 4th to 3rd I believe. Then I got on a long straight away and got up to 65 and she was still in 4th, I went into neutral and back to D and it shifted into OD. Then I came to a stop took off and I felt like I could never get out 3rd gear.

I pulled over hooked up the scanner and I have p0746 and po771 codes up again. I just erased them again and now about to go back home, roughly a 10 mile drive.

At this point I think I’m going to take it to a tranny shop. Thanks for a the solid advice and everyone’s time!

 

I agree w @scottalot - highly entertaining!!!

Don’t throw in the towel yet @sflanagan21 ...

Get her home, clear the codes again then disconnect your battery. Say for a 1/2 an hour to be sure. (BTW, you don’t have to worry about the missus moving it if it won’t start ).

Reconnect the battery, start ‘er up, check for codes then take ‘er out again...

Good luck

 

Thanks, I’ll give that a shot.

 

This might have been covered but I always leave the hood up when doing anything to truck, just as a precaution.

 

I think it’s still pushing air out and still low on fluid. I think if you go thru this process once or twice more, you’ll be good to go. At least I hope so! Good luck and keep us informed.

 

OP's problem is gonna be air sucked into the system. I doubt much if any was damaged with such a short run, but you are going to need to let the air purge out of the system and re-top off the trans. If you drained the pan and then the truck ran for 15ish secs... you probably pumped another 4ish qts out.

 

This is my exact thoughts as well, or it’s my wishful thinking. One thing that I just noticed on the ride home that while in D every time I get to around 40 or give it gas it feels like it jumps out of gear (high rpms and no engagement). Then I shift back to 4th and it engages and is fine.

 

Going back to your original post , we can confirm that you did have the pan off ?
Did you clean the transmission filter ? and the condition of the magnets in the pan ?
A little detective work can sometimes go a long way .
When you used the jumper wire method to check your fluid , is there a chance you accidently jumped the incorrect pins on the OBD 2 Connection ?
Did the wife describe the smell of the burning ?
A transmission will slip when low on fluid making the engine rev up, but its going to take a long while before you are going to smell burning clutch material
Did she mention anything about having to push the gas pedal down extra hard to get the truck to move ?
Was it a burning fluid smell ? burning plastic / wiring smell ?

 

Thanks again for your time Sir! First thing in the morning I’m going to check the level again.

 

Looks like the answers are in the quote a post up.

 

ok the trans pan was not removed .... good to know .
I always get mixed up when people say " pan drain " as it makes me beleive the pan was off .

I suggest a double check of your fluid level at this point . Transmissions have a vent on the top of the alluminum casing . The vent is designed to allow for expansion to atmosphere .
If your vent is plugged , it would make re-filling a little difficult as well as cause some air in the pump once the fill bolt was back in place . The vent is near impossible to get at due to placement . We already know your pump took in a lot of air . In most cases , any air should be gone with the fill hole open even if the vent is plugged
If you feel suction when you remove your fill bolt , you can bet that vent is plugged

After proof reading all your posts , it sounds like you tried your best to fill it correctly .

 

So, how’d it go??