RPM?

fathead1

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I have a 02' 2500 HD xtra cab w/ the 502ci. and Allison trans.
I just bought a 31' weekend warrior, it weighs in alittle over 6000lbs wet, not including a car or toy or whatever I put in it.
My question is, what should my RPM's be when I'm crusing at 55-60 mph.
It has 285 tires
the truck is white with dark grey interior.
and the radio is stock, except for the Brittney Spears CD......
Thanks
 

fathead1

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Throw me a frikin bone here people
c'mon some body help me out.
117 people have read this,
you guys are killing me
Thanks
 

Kritter

Krittro Campbell
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It all depends...seriously. There is a lockout switch available to lockout 5th gear PN #02-07-30-051 that is excellent for towing big trailers. 55-60 with a trailer should be similar to 55-60 without a trailer as long as it is in the same gear and there is minimal give due to clutches and such.

Kris
<A target="_blank" HREF=http://www.barneysprecision.com/fabproducts.htm> Fab Parts</A>
 

sirhk100

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I don't know!!!

'92 Ford Exploder (AKA Dezert Limo cause it's loaded)
 

SpeedMetal

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I have the same truck. I'm assuming you have the allison transmission. I have 4.10 gears in the rear and also have 285/75 tires. I'll let you know what RPM I'm at after I drive home from work. Also, Kritter, is that 5th gear lockout switch a GM part number? If not, who makes it. I'm assuming it keeps the transmission from shifting into 5th when you activate it?
 

Kritter

Krittro Campbell
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Here is where I got that from....it was a GM bulletin

Transmission Shifting In and Out of 4th and 5th Gear (Hunting) When Pulling/Carrying a Load, Unable to Manually Select 4th Gear (Install 5th Gear Inhibit Switch) #02-07-30-051 - (12/02/2002)
Transmission Shifting In and Out of 4th and 5th Gear (Hunting) When Pulling/Carrying a Load, Unable to Manually Select 4th Gear (Install 5th Gear Inhibit Switch)
2001-2002 Chevrolet Silverado HD2500/HD3500 Series

2001-2002 GMC Sierra HD2500/HD3500 Series

with 6.6L Diesel or 8.1L Gas Engine (VINs 1, G -- (RPOs LB7, L18)

and Allison® Automatic Transmission (RPO M74)

Condition
Some customers may comment that when pulling a load, the transmission shifts in and out of fifth gear too frequently, or they would like to be able to select 4th gear manually.

Advise the customer:
A customer who requests the fifth gear inhibit switch must understand fueling systems of diesels and the resulting noise that may be heard. This noise might be objectionable to some drivers. The following is provided in an attempt to enlighten the driver/operator of the vehicle.

Diesel engine fuel injection systems that use a common rail system, as the Duramax™ diesel does, may or may not have what is referred to as pilot fuel injection at the lower engine speeds. Pilot fuel injection is defined as a pre-injection of a small quantity of fuel 5 to 20 crankshaft degrees before the main fuel injection. This pre-injection softens the main injection pressure rise and reduces combustion noise. At engine speeds above 2600 RPM, and a fuel quantity supply greater than 35 cu mm, it is necessary to eliminate pilot injection to meet emission requirements. When driving at or above these speeds, main injection combustion noise may be noticeable. It is normal and not harmful to the engine.

When traveling in 5th gear, the pilot injection to main injection transition is typically in the 136 km/h (85 mph) range, however it may also be heard under heavy acceleration and when pulling loads up a hill during shifts at or above 2600 RPM. Customers that install the fifth gear inhibit switch may encounter the fuel knocking of main fuel injection at speeds around 107 km/h (67 mph) in fourth gear between 2600 and 2700 RPM. This sound is considered normal and is to be expected.

Correction
Install the 5th gear inhibit switch using the following procedure.

Open the hood and disconnect the negative battery cable from all batteries.
Remove the heat shield over the TCM.
Disconnect the TCM wiring connectors.
On vehicles with the L18 gasoline engine, remove the three retainers that retain the Throttle Actuator Control module to the engine side of the cowl, just under and behind the fender to cowl brace, and position the module to the side.
Remove the sound insulator retainer from the left upper most end of the dash insulator and carefully move the insulator to the side.
Approximately 76 mm (3 in) to the right of the stud for the sound insulator retainer, there is a small inward dimple in the dash. This is the pilot for the drill. Drill a 11/16 hole through the dash panel.
Place a thin bead of sealer around the retainer, P/N 22573692, and insert the retainer into the dash panel.
Insert a pocket screwdriver into the center of the retainer to open the retainer.
Remove the instrument panel trim panel from around the IP cluster.
Remove the accessory housing panel with the air bag selector switch and disconnect wires from the air bag selector switch.
Remove the blank panel from the housing panel and install the switch and wire assembly, P/N 15174508.
To the short white wire from the switch, properly crimp and solder a terminal, P/N 12110844.
To the yellow, green and blue wires from the switch, properly crimp and solder a terminal, P/N 12084912.
Position a piece of mechanics wire into the back side of the dash to pull the wiring through the opening in the dash, routing the wires under the HVAC control, and steering column.
Insert the three long wires through the previously installed dash pass through.
Pull the three wires completely through the dash pass through.
Seal the wires to the dash pass through with sealer.
Cut off a 1524 mm (5 ft) section of the wiring conduit.
Route the three wires into/through the conduit.
Position the conduit so it drops down from the dash pass through, reposition the insulator blanket and reinstall its retainer.
Reposition the Throttle Actuator Module and install the retainers.
Route the newly created wiring harness along the vehicle's existing wiring to the TCM area using 3 to 4 plastic tie straps to secure it in place.
Open the gray/clear TCM connector body cover.
Insert the green wire into cavity 20.
Insert the blue wire into cavity 12.
Insert the yellow wire into cavity 28.
Properly close the TCM connector, re-connect the connectors to the TCM, reposition the TCM and install the TCM cover.



Locate the Relay Block-Body to the right and up from the parking brake mechanism. Inspect for a cream colored connector in position 4.
If there is no cream colored connector in position 4, obtain P/N 15306105 and do the following steps.
Remove all terminals and wires from P/N 15036105.
Insert the white wire from the new switch assembly into cavity "E" of the connector.
Place the connector into position 4 of the Relay Block-Body.
If there is a cream colored connector in position 4 of the Relay Block-Body, do the following steps.
Disconnect the connector from the Relay Block-Body.
Insert the white wire from the new switch assembly into cavity "E" of the connector.
Place the connector into position 4 of the Relay Block-Body.
Use a couple of tie straps and tie the newly installed wiring to the underdash wiring.
Reinstall the IP trim bezel.
Reconnect both batteries.
Use normal SPS reprogramming procedures to reprogram the TCM.
Follow the procedure outlined in Corporate Bulletin Number 02-07-30-032 and complete the FastLearn procedure.
Reset the customer clock.
Road test the vehicle in the normal driving mode at 72 km/h (45 mph), 5th gear. When the speed is stable and road conditions are favorable, depress the newly installed 5th gear lockout switch. The LED should illuminate and the transmission should downshift to 4th gear. The transmission then should only have 1st, 2nd, 3rd, and 4th gear operation as long as the switch LED is illuminated.
Depressing the switch will allow 5th gear operation to resume. Fifth gear operation will also be reestablished any time that the key is cycled to the "OFF" position. This is normal.
Parts Information
Part Number
Description
Qty

15174508
Switch kit
1

12051375
Conduit
5 ft

12084912
Terminal (10 per package)
3

12110844
Terminal (10 per package)
1

22573692
Retainer (10 per package)
1

15306105
Connector
1


Parts are currently available from GMSPO.

Warranty Information
Addition of the 5th gear lockout switch is not a warrantable repair. The following information is a suggested repair guide only.

Labor Operation
Description
Labor Time

N/A
Install 5th gear inhibit switch
1.1 hrs

Add
Reprogram Transmission Control Module and perform FastLearn Procedure
0.7 hr



GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information. WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

© Copyright General Motors Corporation. All Rights Reserved.


Kris
<A target="_blank" HREF=http://www.barneysprecision.com/fabproducts.htm> Fab Parts</A>
 

SpeedMetal

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The rpms should be the same, towing or not. The converters in those trannys lock up like a manual transmission in 5th, and I think in some of the lower gears if you are in tow/haul mode. This helps keep the trans cooler. If you haven't towed with the truck yet, you will probably want to look into the switch Kritter was talking about. The transmission does a good job most of the time, but there are those instances when you wish you had control of 4-5 shifting.
 
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