On 5/27/2014 3:20 PM, Poquito Loco wrote:
On Tue, 27 May 2014 15:08:46 -0400, "Mr. Luddite" wrote:
On 5/27/2014 2:56 PM, Poquito Loco wrote:
On Tue, 27 May 2014 14:45:09 -0400, "Mr. Luddite" wrote:
On 5/27/2014 2:19 PM, wrote:
On Sunday, May 25, 2014 3:04:31 PM UTC-4, Mr. Luddite wrote:
On 5/25/2014 8:25 AM, Poquito Loco wrote:
On Sat, 24 May 2014 18:13:59 -0400, "Mr. Luddite" wrote:
On 5/24/2014 4:03 PM, Poquito Loco wrote:
I'm thinking of putting one of these on the Silverado. Anyone had any experience with the concept of
increasing the oil supply to keep it cooler?
http://www.ebay.com/itm/PPE-Allison-Deep-Tranmission-Pan-Duramax-Allison-1000-2000-2400-Series-128051000/121345886743?_trksid=p2047675.c100011.m1850&_trkpa rms=aid%3D222008%26algo%3DSIC.MOTORS%26ao%3D1%26as c%3D22855%26meid%3D7132067336503725629%26pid%3D100 011%26prg%3D9833%26rk%3D1%26rkt%3D10%26sd%3D121335 643997
Followup to my last ...
I assume your Silverado has a transmission fluid temp gauge as well as
an engine temp gauge. My Ford F-250 Super Duty does, I know. If I were
noticing higher than normal transmission temps while towing I'd be more
inclined to add an axillary transmission fluid cooler rather than just
increase the capacity of the transmission pan.
If I am not mistaken your truck has the Allison transmission. From what
I've heard, it is a superb transmission for towing ... probably the best
thing GM has going for it in their trucks. Unless it's getting hotter
than normal, I'd leave it alone. Just my humble opinion.
Here's an interesting and informative piece about Allison transmissions. I'll probably just leave
mine alone for a while. I've never seen the temp get much over 200.
http://dmaxstore.com/index.php?main_page=product_info&cPath=16_363&prod ucts_id=668&zenid=2euu9fpbqf4tmumt6ecj7kbu74
The Pace Arrow Class A motorhome we had for a while had an Allison
transmission. It was the only thing I liked about the whole rig.
Ford sorta copied some of the operating characteristics of the Allison
in the "TorqueShift" transmission used in the Super Duty Series. It
operates similarly to the Allison, including different gear ratios on
the downshifts than the upshifts.
One thing common to both that I assume you do ... always use the
"Tow/Haul" mode when towing. Otherwise, it *may* get hotter than normal.
I'm having a little trouble with "different gear ratios" going down verses going up. There's only one collection of planetary gear sets in an automatic. The ratios don't change.
I think I screwed that up. It's not different gear ratios, but rather
different shift pressures (when using the tow/haul mode). For example,
like the Allison, the Ford Torqshift will sense when going downhill and
automatically downshift to apply engine braking on gas engines, saving
wear on the brakes. Doesn't apply to diesels, since a diesel has no
engine braking.
If I set the cruise control to 45 mph (for example) and am in tow/haul mode, the transmission will
downshift using the engine to keep the speed there. If the cruise control is not set, but I'm in
tow/haul mode, the transmission will sense my slowing down, with or without the brake, and downshift
- if, for example, I'm approaching a red light.
The Ford Torqshift does the same in Tow/Haul. Only difference is that
with your rig being a diesel you don't get any engine braking when
going down hills like you will with a gas engine.
Perhaps not the same amount, but plenty enough to feel.
"TOW/HAUL MODE
An innovative tow/haul mode gives automatic transmissions on select models a dual-mode shift
program. This feature raises upshift points to use more of the engine’s power for strong
acceleration and raises downshift points to help slow the truck using engine braking."
From http://www.gmc.com/trailering-towing/glossary.html
I don't think the "select models" includes diesels. By their design a
diesel engine does not provide "engine braking". However:
You probably have GM's “SMART” exhaust brake. According to the same
website link you provided:
"The new diesel exhaust brake is an innovative standard feature for
DURAMAX models. Unlike the traditional “on/off” diesel exhaust brakes,
the driver-selectable “smart” brake varies negative torque needed, based
on the truckload and grade. This helps reduce brake fade, extends brake
life, and gives drivers plenty of confidence when hauling heavy loads
downhill."