'96 Blazer LS 2 Door 4X4 - Help With Problem - Off-Road Forums & Discussion Groups
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post #1 of (permalink) Old 01-25-2000, 07:14 AM
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\'96 Blazer LS 2 Door 4X4 - Help With Problem

First, let me tell you that what I know about 4X4 operation doesn't cover much more than what button to press, 2HI, 4HI, or 4LO.
I do know that I have to shift into Neutral and be just about at a standstill to engage 4LO. Anyway, I bought my first 4X4 for use in
snow when I lived in the NorthEast. Now I live in the South and have very little use for it. I want to give my '96 Blazer to my daughter,
who still lives up North, but, recently, I detected a weird problem with my 4X4 operation.

Since the vehicle was new, I had never had a problem with the 4X4. In March of '99 the quick lube place talked me into getting my
4 wheel drive serviced. Whatever that entailed, it took quite a long time. The other day, I engaged my 4X4 for the first time (due to
a moderate snowfall) and did I get some surprise! I'll try to describe the problem as best I can.

When I pres 4HI it switches into 4 wheel drive. However, it doesn't appear to shift smoothly, makes kind of whirring sound as I
accelerate, and, I think, it pulls to the right. My 4 wheel drive never operated like this before. When I press 2HI, the 4HI light goes
out but the truck does NOT disengage from 4 wheel drive (it's that obvious). After some period of time I hear a LOUD THUMP and
the 2WD re-engages. Normal operation returns.

Hoping it was something temporary (what else would such a novice hope for?) I tried it again days later on dry pavement (several
times) but the same thing happened.

That said, I called the dealer up North where I had purchased the vehicle new in 1996. Basically, he said there were three possible
causes and, in the worst case, all three would require repair. He estimated a cost of $1,100!!!!

Anyway, before I bring this thing to a local dealer, it would be helpful if I had some idea of what could be going on here. Someone
like me is ripe for a rip-off with something like this because I know next to nothing about it. Does anyone have an idea what the
problem might be and how can I minimize the risk of having the dealer charge me for a major repair while actually making a minor

Thanks for any help anyone can provide.

Ron (Nashville, TN)

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post #2 of (permalink) Old 01-25-2000, 12:20 PM
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Re: \'96 Blazer LS 2 Door 4X4 - Help With Problem

I'd crawl under there and check some fluid levels... T-case, and front differential are the main ones to check... That's a reason I don't like those quick change places... [img]/wwwthreads_images/icons/crazy.gif[/img] People there usually only care about how quickly they do things, and not so much about the quality of it... But anyway, my first guess would be some low fluid levels somewhere...


[img]/wwwthreads_images/icons/cool.gif[/img] '79 Suburban 4x4 454, 6" lift, 35x12.5s & '85 GMC S15 4x4
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post #3 of (permalink) Old 01-26-2000, 06:27 AM
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Re: \'96 Blazer LS 2 Door 4X4 - Help With Problem

Thanks for your reply. I'm hoping that's all that is wrong (not that it isn't bad enough!)

The truck is going into the local Chevy dealer tomorrow. (I'm also getting the ABS Chip update from the recall.)

I should know what the story is by tomorrow.

Thanks again.


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post #4 of (permalink) Old 01-29-2000, 12:19 AM
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Re: \'96 Blazer LS 2 Door 4X4 - Help With Problem

i am also having problems with my s-10 1994 auto 4x4 the parts that they may want to replace are the shift module $236.00 & the shift motor $365.00 my problem is that when i hit the 4hi button the 4hi & 4lo blink but it does not go into 4hi. i replaced the module & it worked for 3 days. i herd from someone else who has this problem & he says that when he has it checked via a diagnostic computer it works for about 3 days then it stops. i think the shift motor on the transfer case may be bad causing the module to trip. the diag computer must reset the module thats why it works for a short time. the motor was not hard to find in a junk yard but forget about the module they just don't have them.

post #5 of (permalink) Old 01-30-2000, 06:20 AM
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Re: \'96 Blazer LS 2 Door 4X4 - Help With Problem An Update And, Hopefully, The Reason For This Mystery

My Blazer has been at the Chevy Dealer since last Wednesday. It's now Sunday. The first call indicated that all components
were working as they should and they could not explain the strange behavior! They asked if they could dismantle the transfer
case and "look around" inside. I said okay.

Even that did not reveal a problem. They referred this to Chevy Tech Support and a probable reason came back!

It seems that when I had four new tires put on my vehicle (Michelin XW4's which were the original tire type), the tire
vendor put P70's in the rear (again, the original size) BUT, they put P75's in front! The front and rear axles, therefore,
were rotating at slightly different speeds! Because the tire sizes were fairly close, this out of synch condition eventually
caused the gears to line up (the LOUD THUMP) and return to 2 Hi! I have been advised that if the tire size difference was
greater, it would not engage or return at all!

So, now they are putting the transfer case back together and on Tuesday I will be at the tire vendor seeking two new tires
for the front. Yes I paid for the 70's so I'm not expecting much of an argument from them.

After the tires are replaced, I'll let you all know if that takes care of the problem. Sure was not something I would have thought
might cause this kind of problem, but, a friend of mine explained that, with the axles out of synch, it is absolutely the probable
cause. What was even a bigger surprise was the fact that I had two different tire sizes. I trusted them and never checked. Guess
I've learned another lesson for the future!

Hoping that by the middle of next week, all will be well, and, sorry for working this in, but it is Superbowl Sunday, so, Go Titans! ;-)

Ron (Nashville, TN)

post #6 of (permalink) Old 02-02-2000, 07:37 AM
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Re: \'96 Blazer LS 2 Door 4X4 - Help With Problem An Update And, Hopefully, The Reason For This Mystery

Just An update. The tire vendor cheerfully changed the front tires, replacing them with P70's and, lo and behold, the 4X4 is
now working just fine! I suppose we should all be aware that different tire sizes between the front and rear can cause some
strange performance problems!

Thanks to all who responded to my post for help.


post #7 of (permalink) Old 02-02-2000, 07:32 PM
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Re: \'96 Blazer LS 2 Door 4X4 - Help With Problem An Update And, Hopefully, The Reason For This Mystery

Good thing it was something that "simple" to fix!

I guess it makes sense that two different size tires would mean two different ratios front and rear, and that probably confused the shifting modules...
At least it makes sense now... [img]/wwwthreads_images/icons/wink.gif[/img]

[img]/wwwthreads_images/icons/shocked.gif[/img]- <font color=purple>J.R.</font color=purple> -[img]/wwwthreads_images/icons/shocked.gif[/img]
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post #8 of (permalink) Old 02-03-2000, 07:40 AM
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Re: \'96 Blazer LS 2 Door 4X4 - Help With Problem An Update And, Hopefully, The Reason For This Mystery

Yes. That's exactly how the Chevrolet Technician explained it to me. Think of one axle rotating at 100 rpms while the
other was rotating at 97 rpms. Because the tire sizes were CLOSE, eventually, the gears synched and returned to 2 WD. He
went on to say that if the tire sizes were a lot different 4 HI probably would have never even engaged.

I am just amazed that the tire sizes were different in the first place. Without looking at the size on the tires you'd never know.
It wasn't obvious at all. Too bad they had to take my transfer case apart BEFORE they discovered this, yet, in the end, I agree.
Thanjk goodness it WAS something this simple.

Thanks again to all who posted.

Ron (Nashville, TN)

post #9 of (permalink) Old 04-07-2000, 08:26 PM
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Re: \'96 Blazer LS 2 Door 4X4 - Help With Problem

Did you ever get your 4x4 fixed? It sounds like you are having the same problems I'm having. I tried a differn't module from a junkyard and that din't work. The switch on the dash is brand new. And if you unhook the battery for a few minutes it will usually reset. The last thing to change is the motor. Is it hard to change? And what did the junk yard charge you for the motor?
Eric Stone

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