Well, first off I need to thank Derek, Mike and Zach (in alphabetical order)for their responses to my questions throughout this project.

I ended up with a BD tq, Trans-go shift kit, billet 4.2 apply lever, some upgraded accumulator pistons, and stock Borg-Warner clutches and steels, new bearings and bushings as required. Both drive shafts had to be altered by 6 5/16".

I took it on a 468 mile round trip to Pa and back and it worked flawlessly. On the highway in OD and LU and cruise set at 65mph, the engine is turning about 1450 rpm and the trans is 165* on the hot line to the cooler-all day long, ambient temp 75-80*. It only has the B&M cooler with the fan on a thermostat. On a hill out of LU and in OD or third it has gone to 210* so I will probably add another cooler or go bigger.

I now have cruise control that works dead nuts on. Before I could only set CC at 62mph never any higher, and on inclines the speed would drop off. Now I set at 65mph and there are no fluctuations, it's right on all the time. I'm guessing because of the tighter converter maybe?

Now my gripe. My mileage before with 307 rears, 727, cruise set at 62, engine turning 2000 rpm, was always around 17-18mpg. Now I top off the fuel, round up to the next quarter and commence driving. Set cruise at 65mph, engine turning 1450rpm, 460 mi. round trip, 90% Highway in LU. Back to the same fuel station, top up to the next quarter, and I got 18.1mpg.

I was very disappointed in that number. Do these transmissions take that much more power to turn?

 

I'm guessing running that low of rpm you are out of efficancy range of the motor.. they like to be ran at 1750-1950 I believe.. Each one will vary depending on how they like to be ran if you get my drift.. What are your boost and EGT running at 65ish.. At 70 I am at 700, 4lbs and 1950rpm with 4.10 gears..

 

where are you monitoring your temps at? 210 is hot for an trans that should not be generating heat though the torque converter. I did not see temps above 180 towing my 6500 pound camper though the mountains (hills for you western guys) here in PA.

 

they like to be ran at 1750-1950

So I need to get my RPM's up, I may have to use OD only, or 3rd and LU.


where are you monitoring your temps at

The temp sender is about 6" down on the hotline to the cooler. I need more cooling area than that B&M unit. What RPM are you turning at 65mph?

 

Hey archer i had the same setup as you on my old black ctd, 47rh and 3.07 gears... great for goin fast, but crap for mileage unless your doing about 75-80mph, too low of rpms wont help mileag on these trucks, i was also running a 33 inch tire. With my new truck i got 4.10s, so ill guess ill find out what kinda mileage ill be getting with the different gears... hopefully better

jason

 

Also ill second runnig a second trans cooler, ill also removed teh water to trans cooler form my motor, i ran two tranny cooler together in front, and i never saw temps above 150... and that was intown idleing around with a trailer, on the highway it was always at 110-140 even towing up hill, my new setup is a Derale fan cooled trans cooler under my truck bed, but im gonna run another cooler with it up front again, just to be on the safe side.... and i already have the cooler anyways with just the dereal i see 180 intown(in bad traffic itll go to 205) while driving though i only see 160..... remember the cooler the trans temp the better!! you could run 100* all day long and be just fine


jason

 

i still don't think something is right for you to be seeing temps as high as 210 even with the one cooler. If your not towing your not even putting a load on the trans and it should work more efficiently than that. I have the factory cooler up front and the factory under the bed cooler and i don't see temps above 150 in or out of lock up.

 

I see about 170* just driving on the hwy locked up.. But I don't think My guage is accurate.. Because last weekend, I was at the dunes and my aux fan finally kicked on and my guage read 220*.. The fan is supposed to kick on at 175*.. So something is up with that..


But I would try 3rd locked up at 65 and see what kinda RPM's that yields..

 

On the highway, whenever I would have to get out of LU, the temps would go to 180* and the fan would maintain that temp. As soon as I was able to use LU again the temps would hold steady at 160*.
It was only on that grade (about 1 mile long in third) that the temp climbed. I will add more cooling surface as I did expect to, I just need to figure out what that will be.