ping GG tranny questions

Do you really think traveling at 85 MPH with over 9000 pounds behind you is a good idea?

just a guess, youve never been to montana?

That would be correct but a blowout on a front tire at that speed with a trailer that heavy gets you just as dead, regardless of the landscape.

as would a blowout at 70, or 60 for that matter. the same goes for the cummins too.....it doesnt like 70 in 3rd either so the same applies.

Your six speed CTD won't like 85 in fifth either:)

Al

2004 600 CTD, six speed, 4X4.

thanks to edge the power wont be the limiting factor. i just dont wanna kill a tranny over it.

Nate, lemme stick my .02 in here.

If I had to choose, I'd pull it with the 04, since its got the better HP, but also because its got the 48RE, which is a couple of steps better than the 47RE in the 01. In particular, the 48 has more clutches in the OD unit, and a stronger planetary set.

As to your cooler, I'd definitely run an aux. cooler, mounted as far from the A/C condenser as possible. At 80MPH, a fan is probably useless, since I doubt any electric fan could move air that fast.

Not sure how much effect, or if its compatible with the Cummins engine management, but I'd also put a cooler T'stat in there, which will lower the coolant temp that flows over the radiator tank mounted cooler, if so equipped.

I'd also install a trans temp guage, just to monitor the temp. Better to stop and relax over dinner than be stopped in the middle of nowhere and wonder if you will get dinner.

Amen on the trans temp gauge, but your '04 CTD w/48RE should be just fine, thank you, towing in OD as long as the tranny doesn't hunt often. I tow about that with my '03 all the time and the trans temp barely rises over

140 degrees. Your 01' should be OK too.

Mike

Nate, I know Gary is a advocate for aux coolers and stuff, but with the Cummins I doubt you will have the need. I've moved a plow over a hundred miles in 85 degree weather and the temp and trans did just fine. One thing that DC didn't screw up was the cooling on the Cummins, gas engines may be a different story.

Roy

I should add that the plow was on the front of the truck, not in the bed.

Roy

Nate;

The problem is lubrication to the OD section

The OD kinda 'sucks hind tit' in that unit..............it gets the leftovers from cooler flow, after the pressure regulator sends fluid to control and clutch pack circuits, plus the cooler flow is HOT fluid, in spite of the cooler

now, your truck SHOULD have a very good cooler alongside the AC condenser on the driver's side, its as good as any aftermarket, plus it is situated for good air-flow, but still, that's a LONG way to tow in OD

but no, I would keep it in 3rd, since then the netire OD gear-set rotates as a locked unit...........the only place I would try OD (and it's your call) would be across IL, IN, IA and eastern SD (or ND if you go that route), as soon as you hit hills or even 'rolling terrain', get back in 3rd

hey, if you're worried about taking extra time, the spare bedroom is available, stop by, we're 120 miles south of I-80 and then you can catch I-72 east to contunue east; or take I-72 to here, then head up to the Quad Cites and I-80 going west

Gary

i appreciate your answer gary. the "to tow in overdrive" question is probably the biggest single debate on tdr (almost like our k&n :) ). at my local dealer, at one in vegas, at one in pahrump, and at two others in big cities out here in the west i spoke to the tranny guy about this. all of them sufggested that i tow with overdrive locked out. they all said the only thing i'd lose is a little mileage that i couldn't hurt the engine. they all felt that overdrive in either the

47re or the 48re won't hold up to towing. they all felt tha the 48re was a significant improvement over the 47re, but not necessarily in the overdrive area. the owner of dtt (tranny specialistics for diesels in washington) also agreed. so, i tow with overdrive locked out. but only due to what i have been told, i am not a tranny tech or mechanically inclined in that area so i rely on the advise of others. i still read a lot of threads on tdr from guys with 47re's and 48re's that have towed big trailers with overdrive on for thousands of miles without any apparent problems at all though, so the debate goes on.

well, as I said, it's a lube issue

consider this:

the Cummins has low-end torque out the wazoo

that means it will lug down before it shifts out of OD; my expereince with this unit is that it takes a sharp jab on the pedal to force a kick-down, if you gradually apply pressure, you can have the pedal to the floor and still not shift down

now, consider the factors here:

1) bogged down, if the converter unlocks, that means gobs of heat, even if it doesn't unlock, the factors below come into play 2) pedal to the floor, pressures to clutch packs to the max, less flow to converter 3) lower ground speed, less air flow thru cooler 4) lugging engine, radiator temp is up (cooler flow is first thru air cooler, then thru radiator cooler, at least on the ones I've seen) 5) lower engine speed means lower pump output, less overall flow

now, one or two of these factors won't do in the OD, but add 'em all up and you have an OD section that is being lubed by an insufficient flow of very hot fluid, under extreme strain as the engine speed drops and individual pulses of power become more pronounced, and the reuslts cannot be good.

G

Forgot to mention that my '00 does very well with 7000lbs in OD, and I live in the hills of PA.

Quick question Gary and not to dispute your points, more for my education. Under full throttle and as slower speeds or RPM's, wouldn't the computer force both an unlock of the converter and a shift out of overdrive?

the 46/47/48 RE uses an electronically-controlled hydraulic 'governor' (shift control) in the first three gears and electronics for 4th and OD

it's a hybrid system that seems to me to have too much 'hysterysis' (lag between input sugnal and output switching), for lack of a better word

if you are in 4th and gradually apply full throttle, it will not kick down until about 30 mph

you have to drive one, loaded down, to get the full feel of what it does and doesn't do

I've tried messing with governor pressures vs throttle pressure to get an earlier k/d, just won't happen

the Transgo kit has a resistor that is added to the governor pressure sensor to get it to 'lag' the GP solenoid a bit, which helps, but not enough IMO

agreed. if possible however, id like to be able to do it with either truck, _if_ gg can come up with something where it could be done without blowing a tranny.

i looked at a couple different setups and they were all mounted under the truck bed with the fan blowing up. these were on a couple street legal ford racing trucks with diesels. i was hoping this would also work for my application.

in overdrive? what is it people are doing that gave the 47re such a bad name?