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2002 chevy trailblazer_lt
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Discussion Starter · #1 ·
My engine blew in my truck a month ago and I finally had a shop install an engine with 32k miles.

A few years ago I broke the 4x4 mechanism in the truck and it hasn't worked since and I never got it fixed. There was never a light lit up on the dash or near the 4x4 knob.

After the new engine was installed it now says on the dash "service 4x4" and it is constantly lit up. Also by the 4x4 knob there is a little "N" lit up. I have the knob set on 2x2.

Why wasn't any of this lit up the time when I had the previous engine?

I am going to have any problems if I dont get it fixed?

Also, Is there anything I should note with a new engine or watch out for?

I drive on a major highway and sometimes go up to speeds of 80mph. Is it ok to go that fast a few days after the install?

Thanks in advance.
 

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2005 chevy trailblazer_ls
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The engine has 32k miles on it. So unless your mechanic rebuilt the engine completely (e.g., new pistons, rings, crankshaft bearings, etc.), it isn't really new. An engine with 32k miles should be adequately broken in so you could do 80 on the highway. I wouldn't worry too much about a run-in period.

As far as the 4x4 issue, I will defer that to one of the 4x4 gurus.
 

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Discussion Starter · #3 ·
The engine has 32k miles on it. So unless your mechanic rebuilt the engine completely (e.g., new pistons, rings, crankshaft bearings, etc.), it isn't really new. An engine with 32k miles should be adequately broken in so you could do 80 on the highway. I wouldn't worry too much about a run-in period.

As far as the 4x4 issue, I will defer that to one of the 4x4 gurus.

Well I should have changed the title..More like "new" to me...:)
 

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do you know how you broke 4wd a few years ago?

I'm going to guess that since the shop knew 4wd didn't work, they disconnected something during the repair and didn't bother hooking the system back up, that's why the indicator is showing Neutral. But again that's just a guess.

To get a better answer we would need to know what's changed, what happened when you tried to use 4wd before and what happens when you try to use 4wd now.
 

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Discussion Starter · #5 ·
do you know how you broke 4wd a few years ago?

I'm going to guess that since the shop knew 4wd didn't work, they disconnected something during the repair and didn't bother hooking the system back up, that's why the indicator is showing Neutral. But again that's just a guess.

To get a better answer we would need to know what's changed, what happened when you tried to use 4wd before and what happens when you try to use 4wd now.

The shop that always worked on my truck didn't replace motors so I had to take it somewhere else..
I blew the 4x4 when i engaged it at too high of a speed. My mechanic said that the transfer case is shot on it. He said that it keeps spinning and they took the axle out that had a problem.
 

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Sounds like the transfer case was jammed in 4wd and he removed the front drive shaft so you could drive it around?

Your mechanic probably did something to trick the system into thinking everything was normal so the service 4wd light didn't come on before.

The new shop probably did something to reset it, didn't bother hooking something up on the inoperable system, or they didn't know 4wd wasn't working and saw something wrong and quickly fixed it causing the system to diagnose itself as broken again.

I wouldn't worry about it but you could always take it back to your original mechanic to get him to do what he did the first time to get the lights to go off.
 

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Discussion Starter · #7 ·
Sounds like the transfer case was jammed in 4wd and he removed the front drive shaft so you could drive it around?

Your mechanic probably did something to trick the system into thinking everything was normal so the service 4wd light didn't come on before.

The new shop probably did something to reset it, didn't bother hooking something up on the inoperable system, or they didn't know 4wd wasn't working and saw something wrong and quickly fixed it causing the system to diagnose itself as broken again.

I wouldn't worry about it but you could always take it back to your original mechanic to get him to do what he did the first time to get the lights to go off.
Thanks!!!! I think you are 100% right..makes sense now..My mechanic is also a firefighter who works at the same firehouse and he just came in and I he prett much said the same thing. I really appreciate the fast and great answer!!!
 

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2004 gmc
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I'm guessing with very little data that the new shop just reinstalled a fuse that the old shop removed to freeze the transfer case in 2WD mode.

Transfer cases have a LOT of moving parts inside. Removing the front drive axle can only be a short-term tactic, since it may deteriorate and then you start grinding parts up inside. Are you intending to never use 4WD mode again?

The mode light being in NEUTRAL is very odd, unless you just have a bad (or dirty contacts in the) mode control switch.

I know of no way the 4WD system can be damaged by engaging at too high a speed. If you engage it under a WOT takeoff during hig torque, that might stress the front axle actuator, but that has nothing to do with the transfer case and its encoder motor. Any chance you can explain more about that incident, so we have a full case history on the patient?
 

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Discussion Starter · #9 ·
I'm guessing with very little data that the new shop just reinstalled a fuse that the old shop removed to freeze the transfer case in 2WD mode.

Transfer cases have a LOT of moving parts inside. Removing the front drive axle can only be a short-term tactic, since it may deteriorate and then you start grinding parts up inside. Are you intending to never use 4WD mode again?

The mode light being in NEUTRAL is very odd, unless you just have a bad (or dirty contacts in the) mode control switch.

I know of no way the 4WD system can be damaged by engaging at too high a speed. If you engage it under a WOT takeoff during hig torque, that might stress the front axle actuator, but that has nothing to do with the transfer case and its encoder motor. Any chance you can explain more about that incident, so we have a full case history on the patient?
I found it odd as well to see the N lit up.

A few years ago while driving in a snow storm my truck was sliding all over the highway and i became nervous and tried putting the truck in 4WD while going about 60mph. I remember hearing a noise but nothing really happpened after that.

A few weeks later i heard a noise while i was driving..it would stop when i stopped the truck. I brought it to the shop and they said that the 4wd was blown. The axle was a temporary fix because i was tired of hearing the noise and didn't have the cashola at the time to fix the 4wd.

I never really seemed to have a need for 4wd because when it snows, normally the roads are plowed by the time i am driving to work and the only reason i would need it is to go on the beach...
 

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I know of no way the 4WD system can be damaged by engaging at too high a speed.

Actually my friend had a old jeep cherokee 2 door and when he was going 60 i believe his friend thought it would be funny to slam it in 4 low and when that happened it blew his tcase and someother things i just cant remember correctly right now
 

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Actually my friend had a old jeep cherokee 2 door and when he was going 60 i believe his friend thought it would be funny to slam it in 4 low and when that happened it blew his tcase and someother things i just cant remember correctly right now
Understood. I should have said there's no way to damage OUR 4WD system, especially going into or out of LO range because we have two safety interlocks. One to make sure the tranny is in neutral, and the other makes sure we're going less than 5 MPH. Once in a while the evil GM design team did us a favor. :thumbsup:
 

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Thank god for them putting in safety switches i was going 80-90mph on the freeway and i was messin with my shifter and accidently put it in REVERSE!! :duh: luckily it kills EVERYTHING on the TB before it goes into gear :hopeless
 
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