Full Synthetic ATF ??

[folkenheath]

Well, I am not sure what to say. I see you mentioned B&M conflicts with TCI, both are reputable companies and one of them has to be wrong. I also found this...which agrees with my assumption...

http://www.areds.com/wp-content/uploads/Cooler-line-chart.pdf

I believe TCI is wrong simply because I don't see why they would change the supply line location in the case where it intersects the pump. However, from looking in my ATSG manual I cannot find anywhere that it says which line is which. And from looking in my Transtar catalog I see that the pumps did change in 97, which is when they changed the return line location. So although it is possible they changed the location of the cooler supply line, I would doubt it because it would just mean more expensive changes in the pump vs just blocking off the return passage.

Also, if you look at the old and new cases it appears that the top fitting has the same "boss" traveling toward the pump(the front of the trans), which would mean the passage location of that fitting did not change at the pump intersect, and is more likely to be the supply for both styles of cases.

So, with all this conflicting information, one way to know for sure is before you hook up the lines, start it up for one second, or just spin the engine over without starting just long enough to see which fitting the fluid comes out of. Or disconnect one cooler line and see which way it is flowing. Just make sure you shut it off before you run the pan low enough the pump starves of fluid, and don't put it in gear, make sure its in park. Or get everything warm and see if you can measure which line is cooler coming out of the cooler.

 

[miniwally]

And Dex 6 is synthetic fluid, although I have noticed it shifts softer when installed in older computer controlled trannies.

If you want it to be a little tougher than factory without internal modifications, try a transgo shift kit.

I have heard that in the early auto transmission years they had to make the fluid sticky to get the clutch packs to holdup.

Now with modern stuff being computer controlled and clutch applying being so much better they are trying to make the fluid slippery so they can actually get the shifts to soften up.

I've been running some pretty hot tuning on my D-max since it was new and have been running a few quarts of amsoil slick shift in it for several years now to firm it's shifts back up. It's starting to feel a bit off again and I suspect I get one more round of sticky fluid and then it's going to be rebuild time, I just hope I can get from the 160,000 miles on it now to over 200,000 miles before either rebuilding the transmission or selling the truck.

We did run some amsoil torque shift? which is the amsoil version of oil for the new diesel truck transmissions one year in Vegas to Reno and could tell a difference in the way the race car trans shifted, It was softer for sure.

 

[85chevyk30]

Synthetic ATF fluid

I have used Amsoil synthetic oil in my engines, gear transmissions and differentials and chain saws for 35+ years with good success - worth the money! Since a lot of other companies started producing synthetic oils I have tried different ones with mixed results. I have an oil analyzer and I can tell which ones do the job and last the longest. I tried a brand of synthetic ATF sold at Advance Auto when I had my 700R4 rebuilt. Within a few hundred miles the transmission went south. I took it back to the rebuilder and he rebuilt it at no charge. I asked him to save the synthetic ATF and put it back in the transmission. He did. A few hundred miles later it went south, again. He rebuilt it again and put non-synthetic ATF in. End of problem. He surmised that the synthetic ATF was reacting with the clutch material and causing it to disintegrate. Another guy on this site says he has good luck with Amsoil synthetic ATF. They make a good product and that may be the way to go but I will stick to a good brand of non-synthetic ATF and change the oil and filter on a regular basis. An oil analyzer helps! Good luck!

 

[big-blue]

Amsoil synth ATF saved my a$$ when the OD wasn't kicking in and was approaching 220F temps. I have since fixed the OD issue and back to 140/160F (highway/city, respectively).

 

[Greg Ducato]

The lower line on the earlier 4L80E is the return line, the later trans with rear line uses that line for return.

Synthetic fluids are worth the money if you subject the trans to any kind of abuse, and even if you don't. Automatic transmissions produce friction, friction produces heat and heat degenerates fluid and its additives. For best long term durability synthetics' are always the way to go. All automakers use synthetics in new production automatics and they have enjoyed the benefits of cooler running, less friction and longer durability and service intervals.

 

[cuervo]

Well, I tow around a 5000lb boat and a travel trailer that's just a bit heavier. I'm adding a deep sump B&M aluminum pan and rotating the external cooler(seems ports facing down aren't good).

 

[Greg Ducato]

I would recommend running through the radiator cooler first, then through the auxiliary cooler then back to the trans for best results. The deep sump finned pan looks good, seals nicely but wont do much to reduce temps and can uncover the filter pickup at extreme angles. When you are running down the road your system will pump over a quart every 20 seconds, the fluid doesn't stay in the pan long enough for the pan to chill it much. On an off road vehicle I would choose a shallow version.

 

[cuervo]

I would recommend running through the radiator cooler first, then through the auxiliary cooler then back to the trans for best results. The deep sump finned pan looks good, seals nicely but wont do much to reduce temps and can uncover the filter pickup at extreme angles. When you are running down the road your system will pump over a quart every 20 seconds, the fluid doesn't stay in the pan long enough for the pan to chill it much. On an off road vehicle I would choose a shallow version.

That's how I have the lines running already.

The new pan comes with an extended pick up so not much chance of the filter not being in the fluid at any point in time or angle. The fins on the pan may not cool the fluid much but aluminum dissipates heat better then the stock pan. The bonus is the extra 3.5 quarts in the pan so it will stay in the pan longer because there is more there.

 

[Greg Ducato]

It's a good plan

 

[cuervo]

I can 100% confirm the lower line on the 91 model 4l80e IS the return line.

edit

now I thought the pressure line should run the the bottom of the radiator and the return line, when stock, should come from the top. That isn't how it was set up from the factory. The pressure line went to the top of the radiator and the return line is on the bottom.

Is either way better?

/edit

 

[cuervo]

Just doing some more searching and reading. This graphic goes against what I've learned.

What a minute. I was looking at the arrows on the route... they have them going against each on one line!!!

 

[cuervo]

Ran a flow test with the new radiator and getting about 1.2+ quarts every 10 seconds going through the rad and the external cooler. I'll get a road test in tomorrow.


Thanks everyone.

 

[beags86]

I can 100% confirm the lower line on the 91 model 4l80e IS the return line.

edit

now I thought the pressure line should run the the bottom of the radiator and the return line, when stock, should come from the top. That isn't how it was set up from the factory. The pressure line went to the top of the radiator and the return line is on the bottom.

Is either way better?

/edit

From my experience It doesn't matter which way it runs through the rad. But I have been wrong before.

 

[big-blue]

I can 100% confirm the lower line on the 91 model 4l80e IS the return line.

So, that means that the TCI page is wrong then - as they indicated that the upper one is the return.

This is good info because I am redoing my radiator and trans cooling setup. I was about to embark on doing my own test to see what lines were the in & out.

 

[cuervo]

So, that means that the TCI page is wrong then - as they indicated that the upper one is the return.

This is good info because I am redoing my radiator and trans cooling setup. I was about to embark on doing my own test to see what lines were the in & out.

Yeah, kind of odd that a major trans builder like TCI would have that listed wrong. I did send them an email so hopefully they change it.

 

[sponsoredbydad]

From my experience It doesn't matter which way it runs through the rad. But I have been wrong before.

From a pumping standpoint you always draw from the bottom where it pools so as not to suck air. Dump to the top, pump from the bottom.

I run full syn seems to help with the heat.

 

[beags86]

From a pumping standpoint you always draw from the bottom where it pools so as not to suck air. Dump to the top, pump from the bottom.

I run full syn seems to help with the heat.

Makes sense, but I also look at it from the standpoint of the pressure its pumping through the cooler at. The pressures from the trans are so high I doubt it would pump air. But I will make sure my stepper is set up like this when I get to that point. Another good tip for my brain bank.

 

[folkenheath]

I can 100% confirm the lower line on the 91 model 4l80e IS the return line.

Good to hear we have a confirmed answer. Nice work.

Just doing some more searching and reading. This graphic goes against what I've learned.

What a minute. I was looking at the arrows on the route... they have them going against each on one line!!!

It appears all fluid goes into the radiator, and none comes out! All fluid must come from the trans cooler.

Nice catch.

Makes sense, but I also look at it from the standpoint of the pressure its pumping through the cooler at. The pressures from the trans are so high I doubt it would pump air. But I will make sure my stepper is set up like this when I get to that point. Another good tip for my brain bank.

The cooler lines don't see full pump pressure, they lower the cooler line pressure on purpose to help prevent a line failure. However, pressure still might be 30 - 100 psi and with as much flow as it has through there any air in the line should be flushed out pretty quickly no matter which way you run it. But it can't hurt to plumb it whichever way you feel is better. Flowing out the bottom is less likely to pump air, but flowing out the top is less likely to trap air. Which one is better depends on the application and in this one I don't think it matters due to the fluid velocity in the system.

 

[beags86]

The cooler lines don't see full pump pressure, they lower the cooler line pressure on purpose to help prevent a line failure. However, pressure still might be 30 - 100 psi and with as much flow as it has through there any air in the line should be flushed out pretty quickly no matter which way you run it. But it can't hurt to plumb it whichever way you feel is better. Flowing out the bottom is less likely to pump air, but flowing out the top is less likely to trap air. Which one is better depends on the application and in this one I don't think it matters due to the fluid velocity in the system.

I know an 80 is around 30-50PSI through the cooler, I just rebuilt mine in my DD a few years back and added another cooler and wanted to make sure it was good. On hindsight I think I always plumbed them from the top down as that just made more sense to me.

Edit: in case anyone cares trans pressures are 180-200psi and cooler pressures are 30-100psi as heath said,
even 30psi should be plenty to push air.

 

[77_Jimmy]

what does Phoenix transmission use in the transmissions they build in their shop