Newly rebuilt 727 overheat issue

[myfeather626]

I just had a 727 bult for my 74 charger 400ci, it has a 292dur 509lift Mopar purple cam, Harland Sharp roller rocker, trick flow 270 heads, Chrysler 8 3/4 rear with 3.55 GR, hays twister full race 10" converter @ 3200 stall, and a deep pan, I am running atf+4 in it.

So here is the low down, when I installed the transmission a month or so ago with a broken wrist it seemed to be in a bind and would not let the torque converter slide forward to meet the flex plate. So, I decided to remove it again and see what the issue was. As I loosened the bell housing bolts the converter freed up and slid forward to meet the plate, so I snugged the bell housing bolts again. I checked the end play of the converter travel; it was over tolerances by 1/16. So, I added four grade 8 washers between the flex plate and converter to make the difference. Remeasured, and it came just into tolerances. Finished the installation and added 4qts fluid warmed the engine to normal operating temperature and added 5 qts more fluid after cycling through all gears to bring the level full.

Test drove apx 1 mile and parked the car because the transmission cooler line was leaking where i had installed a compression t-fitting on the exit line of the trans for a temp sensor. I repaired the leak and dove the car to my local exhaust shop, and then to a local body shop to make an appt for alignment, apx 10 miles. I did run it a little bit to explore any issues that I might have with the car, but not too much seeing as how the front end was all out of alignment. I got a plastic/rubber melt smell at a stop light which i assumed was all of the new stuff installed on the car and when i pulled into the driveway i looked at my trans temp gauge and was shocked to see it at 230f degrees. I pulled in the shop killed the engine and put a drum fan on it to cool it down quick. FYI i did prime the converter before instillation.

Now my first thought was that during the instillation when I couldn't move the converter forward was that I may not have gotten the pump ears lined up and broke them off destroying the pump. I've heard of it happening to others and I thought for sure even though I was careful to seat the converter, i had messed up and broken them off. My wrist still being broken I decided to have a friend remove it for me so we could replace the pump flush it out and start over. When we got it out, I looked inside, and the pump ears appeared to have no damage there and there were no odd wear marks on the converter. I took a section of hose and with lung pressure blew through the cooler line to be sure it was clear, I blew fluid from the line which suggests a functional pump. No problems there. I blew into the entrance port of the trans, again clear. I blew through exit port of the trans coming from the pump, there was some resistance, and I could hear it make a little clicking noise, but that would be expected as I was blowing the pump around a little which further suggests with no obvious visual damage that the pump is not damaged.

The converter did suggest the use of a trans cooler that i did not think was necessary because I am running a giant four core radiator. I have since purchased a 19 core, stacked core cooler from Earls auto plumbing and an oil thermostat that I will install. I plan to pull the pan and check the pickup for blockages. I checked my tire size because I've read that under 22" diameter tires can cause overheat issues, but my 14" tires measure 25" diameter, so I don't think that that is the problem, but I did order some 15s for it. My trans builder suggested that I use type F fluid but with what I think I know about f, that it swells bands for a tighter shift and is used by racers who rebuild their trans often, I decided to use a full synthetic for longevity with it being a new rebuild with newer materials being used in the bands etc. Hence my decision for atf+4. So back to my original question, what could be causing overheat? What other tests can I perform? Should I take it back to the builder? That could be a problem and story in itself that i can explain if needed. Any thoughts/suggestions please?

Fluid? My suggestion! Put the Correct fluid in! Just my suggestion who Built the trans?

 

[Lefty71]

Fluid? My suggestion!

See post #20..... don't flog a dead horse.
I know of a whole lot of people who have run Type F in everything for eons..... reason being that it has the least additives. I've not heard of failures from it use regardless of manufacturer. B&M used to, maybe still do, recommend it in lieu of their very expensive "Trick Shift" fluid.

 

[myfeather626]

See post #20..... don't flog a dead horse.
I know of a whole lot of people who have run Type F in everything for eons..... reason being that it has the least additives. I've not heard of failures from it use regardless of manufacturer. B&M used to, maybe still do, recommend it in lieu of their very expensive "Trick Shift" fluid. ATF was the go to for my torque flights after having them built. I guess anything can be used but at what cost?

I have only owned 4 Speed cars of late meaning for the last 20 years. However I was always told and experienced fluid makes a big difference. I just would not run Type F.

 

[myfeather626]

See post #20..... don't flog a dead horse.
I know of a whole lot of people who have run Type F in everything for eons..... reason being that it has the least additives. I've not heard of failures from it use regardless of manufacturer. B&M used to, maybe still do, recommend it in lieu of their very expensive "Trick Shift" fluid.

I have only owned 4 Speed cars of late meaning for the last 20 years. However I was always told and experienced fluid makes a big difference. I just would not run Type F. ATF was always the goto fluid for torque Flights after having them rebuilt I am not saying something else can't be used however when trying to figure out an overheating problem maybe the fluid is expanding the Band maybe the pump went out or it just needs adjusting anything could be possible. I just Know if a 727,904 rebuilt properly are Bulletproof!

 

[Geoff 2]

Not the trans fluid. Use some logic. Millions & millions of trans use Dextron & type F. They do not overheat.

 

[Wietse]

Use the recommended oil as advised, no need to overthink it.
Going with high stall converters causes more heat, it does not matter what oil brand you use.
If there is more heat generation than normal, the standard cooling system will no longer be sufficient, no matter what oil type you have.

 

[myfeather626]

Use the recommended oil as advised, no need to overthink it.
Going with high stall converters causes more heat, it does not matter what oil brand you use.
If there is more heat generation than normal, the standard cooling system will no longer be sufficient, no matter what oil type you have.

I guess you are correct I am a bit older and were told to only use the ATF or Dextron. Since someone has built this aforementioned convertor and Transmission sounds like it was rebuilt improperly if the oil has no affect on the bands. Lol!

 

[Lefty71]

told to only use the ATF or Dextron.

Type F is ATF. Dextron is also ATF, and so is Dextron III as well as Mercon.
Type F just happens to be one that has fewer additives.....not gonna cause any swelling any more than it's supposed to.