2004 z71 silverado

[michele44]

my service 4wd light came after I got my oil changed and diff's changed. What should I be looking for ? None of the lights on the board were the 4 wd and 2 wd buttons are. Please help !!!

[ukrkoz]

Originally Posted by michele44

my service 4wd light came after I got my oil changed and diff's changed. What should I be looking for ? None of the lights on the board were the 4 wd and 2 wd buttons are. Please help !!!

1. you changed oil in differential or had differential changed?
2. no sweat. time for your 4wd switch to go bad. it's roughly 70 bucks item dealership and 5 minutes to replace, at least - on my 2000 model. just yank the dashboard cover off, lower steering wheel all the way down, unlock gear shifter and shift it into 2nd gear, remove cover, pull out switch, replace switch with new one, reposition cover.
unless they improved the looks so much that now it takes longer than that.
also, if you want to, you can pull switch out, remove its cover, get to the contacts for push buttons, and clean them with pencil eraser.
that's why oldtimers buy them trucks with floor shifter only. none of that trouble.
3. don't forget to change transfer case fluid either! along with front differential one. it has transmission fluid, front and rear differentials, and transfer case ones.

[MT-2500]

Does the shift buttons light up key on bulb check?
If not.
Or no lights check fuse.
If service 4X4 light is on check transfer case computer for codes.
Post back code no.
MT

[j cAT]

Originally Posted by michele44

my service 4wd light came after I got my oil changed and diff's changed. What should I be looking for ? None of the lights on the board were the 4 wd and 2 wd buttons are. Please help !!!

this may only be a wire connector that was damaged by the work done to your vehicle...If this light appeared some time after the work was done I would see if it goes into 4 wheel drive...if working properly the light should flash twice...the longer it flashes the more it points to transfercase...also check the fuses ....the dash 4X4 switch has also been a problem as the solder joints need to be resoldered [cold solder joints]


how often... in miles do you replace the transfercase fluid [TRAC II]?????

[ukrkoz]

Originally Posted by j cAT

this may only be a wire connector that was damaged by the work done to your vehicle...If this light appeared some time after the work was done I would see if it goes into 4 wheel drive...if working properly the light should flash twice...the longer it flashes the more it points to transfercase...also check the fuses ....the dash 4X4 switch has also been a problem as the solder joints need to be resoldered [cold solder joints]
how often... in miles do you replace the transfercase fluid [TRAC II]?????

j, allegedly they put 80 weight oil into diff instead of 90 weight. and truck was smart enough to catch on that and throw service light on.

[MT-2500]

Originally Posted by ukrkoz

j, allegedly they put 80 weight oil into diff instead of 90 weight. and truck was smart enough to catch on that and throw service light on.

I do not think the truck can tell what weigh oil is in the rear ends.
But it is pickie about what transfer case fluid and transmission fluid you use.
MT

[ukrkoz]

Originally Posted by MT-2500

I do not think the truck can tell what weigh oil is in the rear ends.
But it is pickie about what transfer case fluid and transmission fluid you use.
MT

i think it's 4x4 as it's Z71 and they had trans and front diff fluids changed. i still do not believe that truck will tell the difference, and mine is running on all kinds of non-gm synthetic stuff without any complaints, but if that's the case - good for the owner. let's see how goes it, hopefully, simple refill with proper weight will do the trick.

[j cAT]

Originally Posted by ukrkoz

j, allegedly they put 80 weight oil into diff instead of 90 weight. and truck was smart enough to catch on that and throw service light on.

I believe they screwed up the job somehow and told this owner a B/S story......I can't say for sure but it's 80-90wt gear oil, or 75-90wt synthetic, and I have never heard or read anything that can measure/detect the difference...


on 2000 4x4 in rear with locking diff 75-90wt syn and on front diff 80-90wt hypoy C gear oil ...


I hope they did not put gear oil in transfercase!!!!!

[wafrederick]

I know of 3 rear ends going out due to synthetic gear lube and my father's friend Rich has seen this.Problem with synthetic gear lube is that it is too hard on the ring and pinion.My father's friend Rich has seen ring and pinion sets ruined down to a size of a pencil tip due to synthetic gear lube.Plus synthetic gear lube is not recomended for Detroit Lockers,screws it up.

[j cAT]

Originally Posted by wafrederick

I know of 3 rear ends going out due to synthetic gear lube and my father's friend Rich has seen this.Problem with synthetic gear lube is that it is too hard on the ring and pinion.My father's friend Rich has seen ring and pinion sets ruined down to a size of a pencil tip due to synthetic gear lube.Plus synthetic gear lube is not recomended for Detroit Lockers,screws it up.

I can't say what happened to those owners and the methods that the repair/lube tech used...It is my observation that most repair/lube centers will not remove the inspection cover !!!!!! This is sure destruction to these diff's as the magnet is fouled with metal chaff, and this not being removed and the diff wiped clean caused the diff failures.. also many never replace these fluids at all until it is toooo late... when I did my diff it was at 30,000mi and I found the magnet with much metal debris ,,, at 60,000mi less,,, and at 95,ooo very little ...this is all with mobil 75-90wt synthetic and with that reduced magnet debris and the diff's perfect operation I would have to say now at 120,ooo your assumption is incorrect...



obviously the diff cover removal is a cost factor to the repair center , and when the diff fails because of the metal debris non removal is wearing out the gears/bearings.. its just a guarrantee of more work down the road...