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Tranny Question.

GMC_MTR_4X4

By GMC_MTR_4X4
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GMC_MTR_4X4 Enthusiast

GMC_MTR_4X4

Posted
Posted

Hello there, I have a 01' GMC Sierra 5.3L 4x4 ext. cab. I have about 100,000 miles on the truck now and have pulled with it for a while. Just lately I have noticed when the tranny shifts from 2-3, right in the middle of the shift the RPM's quickly go up 500 and back down, as if something is sliping no noise though. I recently had my tranny Flushed and it didnt seem to help at all. I realize the mileage on the truck is getting up there and it could very well be time for a rebuild but I have talked to a couple mechanics and they have said let it pile up before you get it rebuilt, does this sound right? how serious is this problem? :thumbs:

torx Enthusiast

torx

Posted
Posted
Hello there, I have a 01' GMC Sierra 5.3L  4x4 ext. cab. I have about 100,000 miles on the truck now and have pulled with it for a while. Just lately I have noticed when the tranny shifts from 2-3, right in the middle of the shift the RPM's quickly go up 500 and back down, as if something is sliping no noise though. I recently had my tranny Flushed and it didnt seem to help at all. I realize the mileage on the truck is getting up there and it could very well be time for a rebuild but I have talked to a couple mechanics and they have said let it pile up before you get it rebuilt, does this sound right? how serious is this problem? :thumbs:

 

 

 

 

that called flare/flare shift-bascially one component releases before the other applies so the transmission is not driving at a fixed ratio (neturals), mometarily. The result is a noticable flare in engine rpm.

 

Not a transmission pro so I will refrain from advice on a fix. I'm getting ready to upgrade my valve body and will post a how to, what's different, etc when I'm done.

drewhelm Enthusiast

drewhelm

Posted
Posted

Just started experiencing the same problem in the same year and model truck with 115K miles on it. Only thing is mine make a little bit of noise in any forward gear....

 

Getting it checked out this afternoon.

ChevyTech007 Enthusiast

ChevyTech007

Posted
Posted

This sounds like your problem.

 

Subject: 4L60E / 4L65E Intermittent Neutral from a Stop or 2-3 Shift - kw flare information launch slip #PIP3002C - (09/22/2004)

 

 

 

Models: .

 

 

 

 

--------------------------------------------------------------------------------

 

The following diagnosis might be helpful if the vehicle exhibits the described symptoms in the PI.

 

Condition/Concern:

The 4L60E/4L65E may experience an intermittent neutral condition while accelerating from a stop (category one) or while driving (category two).

 

Category One: Intermittent neutral condition occurs on accel from a stop with the shifter in D4. The neutral may be associated with an engine flare and then a harsh engagement. The Transmission Fluid Pressure Switch should read correct signal "A" High "B" Low "C" Low.

 

Category Two: Intermittent neutral occurs during 2-3 shift and the transmission will not have 3rd or 4th gear. The "B" Shift Solenoid is not bleeding off during the 2-3 shift allowing the transmission to stay in 2nd gear and return to first during the 3-4 shift.

 

Recommendation/Instructions:

Category One:

 

Attempt to duplicate the condition and if possible capture a snap shot of the condition with the Tech 2 or VDR while monitoring the transmission line pressure with a gauge. The following should be monitored to ensure the PCM is not commanding a higher then first gear start.

 

The Transmission Fluid Pressure Switch. The correct reading for D4 is as follows "A" High "B" Low "C" Low.

 

VSS should be monitored at stop to ensure that it is reading 0 MPH/RPM

 

Commanded Gear should be first Solenoid Status "A" on "B" on

 

Engine cooling fan operation should be noted and discussed (TSB 01-06-04-052, 02 Trailblazer, Envoy Bravada with 4.2 engine) Transmission line pressure low during the condition may cause an intermittent loss of pressure and neutral condition. Some customers may describe a launch in a higher then first gear as a neutral due to the greater amount of engine noise associated with the launch and lack of acceleration. In the event the dealer is unable to duplicate the condition, the dealer may consider installing an entire transmission shift cable, inspecting the forward clutch seal/piston and inspect for a broken or missing oil pump spring (two springs on units built 15-DEC-03 or earlier, one spring on units built 16-DEC-03 or later, reference bulletin 04-07-30-006)

 

Installing Transmission Assemblies, Lo Roller and the Forward Sprag have not been proven to be an effective repair.

 

Category Two:

 

Attempt to duplicate the condition. The "B" Shift Solenoid should be air checked for being restricted and not exhausting. However air testing the solenoid may remove the restriction. The "B" Shift Solenoid should be replaced.

 

.

 

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance.

 

Models:

(99-05 Buick Cadillac Chevrolet GMC Hummer Pontiac Light Duty Trucks and Cars)

 

.

drewhelm Enthusiast

drewhelm

Posted
Posted

Pulled pan yesterday and found magent completely covered with metal shavings and quite a bit of larger metal debris in the pan.....time for a rebuild.

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