2004 Chevrolet Avalanche

Looking forward to more info and pics as you get to know it.

I found out after buying it that my S10 is a full house ZQ8 factory limited edition.

So it cost me some money to get it back to factory spec, but I love it.

There are clever guys out there who read these like a comic strip.

Well, tomorrow is the day it gets delivered. Looking at a time line of getting it back roadworthy and MoT'd for 1st August.

I got the car back last Tuesday with the welding having been done, a new front to rear brake pipe and a full MoT. Since then I have done about 200 miles in it. It surprised me how quickly I got used to left hand drive despite the width of the vehicle and the narrow twisty roads that litter the area we are in.

The biggest surprise though was this:



This is far better than I ever managed out of a Range Rover (usually 12 - 14 mpg). Also bear in mind that this was pottering around locally and not on any long runs. The car runs on LPG which costs between 75p - 99p per litre in my locality. So even at 99p/litre its still equivalent to 30mpg on diesel. Its cheaper to run than my Voyager!!

From the moment I drove it the stereo was driving me nuts. It has had the original stereo replaced with a Kenwood head unit connected to the installed Bose amplifier via an adaptor box. This box is supposed to let the Bose amp think the original stereo is fitted and work seamlessly with it - except it didn't. Generally it didn't work at all other than randomly switching itself on whilst driving and causing me to jump!! Clearly this could not continue.

So this is the Kenwood system:



And its connected through some rather questionable wiring to this adaptor



After spending several hours investigating the box and the cars wiring on line, and playing around with the wiring I came to the conclusion that the fault lay within the box. A shame as these are very expensive and if it were working it would be an easy way to upgrade the stereo.

So I decided to rip all this out and start again. I wasn't that bothered about the Bose amp. I suspect that the amp itself had internal EQ as is often the case with Bose home systems. This gives a very bass heavy and toppy sound. There is a sub woofer built into the centre console which I would initially loose but for the time being I'm not that bothered. I'll add another amp at a later date to get it working again. The cars sound was impressive on first acquaintance but not great overall. The old adage is that Bose stands for Buy Other Sound Equipment. Maybe so but I do have a pair of old Bose 301 S2 domestic speakers that I like a lot.

So the first thing to do was to get to the amplifier. It resides in the bottom of the centre console. Getting to it was easy as everything either unscrews or unclips.



It was a case of unclipping the connectors and extracting the loom to get access to the speaker cables. I then had to decipher which cable went where





It appears that there are two types of Bose system installed in many of the GM products of this era, Standard and premium. Mine is the premium as it has the subs. There is a lot of contradictory information on the net about the wiring of these systems, all being slightly different depending on the vehicle its installed in. Naturally there is virtually no information about the Avalanche installation.

So armed with several different wiring diagrams from other models and a test meter I went about sorting this rats nest out. I then had to run speaker cables back up to the head unit as I was intending on using its own internal amplification.





Having got these in I had to sort out the power connections. As with most head units, I needed a permanent 12v feed and an ignition (acc) switched feed. The permanent feed was simple, the original radio connector already had one. The ignition switched feed was a challenge though. It appears the original system used the cars data bus to turn itself and the amp on. So I had to search for a suitable feed elsewhere.

Again, after more research and a probe around with a test light I discovered a junction box in the drivers footwell that had the required supply on it so I ran a cable from there up to the head unit.

So I now had power and speakers connected. Time to try it out. Hmm, no sound from the front passenger door but the tweeter in the screen pillar trim was working so the fault must be either with the speaker or the wiring in the door. Off with the door trim then.

The speaker is held in by a strange clip system. Sounds odd but it was rock solid and a pig to release.



Having got the speaker out and disconnected the wiring looked fine. The speaker cone moved as I would have expected it to but a quick check with a multimeter showed it to be open circuit. Everything looked and felt fine so I investigated further. Putting a meter across the wires where they pass through the cone showed a 6 ohm resistance. So the speaker itself was fine. Closer examination with a bright light and a magnifying glass revealed that the terminals in the speaker connector were tarnished



After attacking them with a scalpel and a cut down nail file I had 6 ohms at the terminals. Back out to the car and connect it back up. Yes!! it worked. So now all I had to do was put it all back together.





So it now all works, looks good in the dash and actually sounds pretty decent. Obviously the steering wheel controls don't work but as the stereo is right by the wheel its not exactly an issue.

Next thing I need to do is add a reversing camera. I'm going to wait until I have replacement reversing lights (on order) to replace the broken ones currently fitted as they will feed the camera power.

As grizz and others have said, its not about miles per gallon but smiles per gallon!! Every time I get in the truck and start it up the rumble of the V8 brings a smile to my face. Surprisingly the wife loves it too!

So whats this mid gate malarky about with this truck then? Basically a very good idea that makes the truck very versatile.

Firstly you have the 5ft bed with a tough waterproof cover on it. The cover is strong enough for two people to stand on.



The cover is in three parts and unclips to give an open bed



Whilst still giving a spacious car like rear seat



The rear seat can be folded forward and the 'Mid Gate' laid flat leaving the cab glass in place to give a full 8ft x 4ft load area



If you need to carry larger items the glass can be removed and stored safely in the front of the mid gate



Giving a pretty decent load area



The mid gate can be raised with the rear window stored and the seats can be put back into position leaving the glass out to give extra ventilation



It's a pretty damn versatile system.

To be honest, I didn't really have the space or time either and if it wern't for the fact that the car was just down the road from where I live I probably wouldn't have bothered with it. Solved the space problem by scrapping off a Renault Laguna that had been sitting around since 2019, one out one in. Also had to promise the boss that I would get rid of three other cars too. So the Merc covertible is going (it never gets used these days anyway), The 1992 Range Rover is going (very rusty but repairable, I just haven't got the will or the time to do it) and the Merc C180 will be MoT'd and sold. Time issue was solved by getting a local garage to do the welding and brake pipe. Whole job including an MoT came to £300 which I thought wasn't bad

One reason I wanted this was to use as a tow car for our caravan. The van is on the weight limit of the Voyager and from past experience I can say that bad things happen to auto boxes when operating at their limits!!

The Avalanche has a few issues that need sorting out. I doubt that the transfer box has ever had an oil change as it is damn near impossible to get GM Auto Trak 2 fluid in the UK. I've found a supplier now and it should arrive on Wednesday. I'm also going to do an oil change on both differentials and the auto box (along with its filter screen). It has a bit of a drone above 40 mph but that might just be the tyres. I've had BFG All Terrains on the HiLux in the past but they didn't seem quite this noisy. Having said that, the diesel in the HiLux drowned out most noises anyway!

The LPG system needs a service too. It stumbles a bit when pulling away quickly (its fine on petrol). I have the service record sheet for the LPG installation and if that is anything to go by it has not been serviced since it was installed 45000 miles ago!

The parking brake also leaves a lot to be desired so I'm going to have to look into that too. Last MoT had it as an advisory that it barely reached the requirement of the test and it certainly hasn't been dealt with since. Its a dead easy sytem to work on though and I suspect that the adjusters have siezed up.

Yeah, I have had some interesting and entertaining meetings with other vehicles. Funniest are the idiots in vans that think they can use their size to bully people out of the way!! The look of terror on their faces is priceless.

To be honest you get used to the size very quickly. In fact its only about an inch wider than my Voyager but it does have significantly greater road presence.

On Wednesday the Chevrolet went in to have the a/c leak traced. It was filled up a couple of weeks ago and lasted three days before all the gas had leaked out despite having passed the leakdown test. The leak was traced to the condensor. Didn't surprise me as it looked a bit ropey. So I've got to order a condensor, drier and seal kit. Rediculously cheap in America (£60.00 for the lot). Of course the shipping cost will just about double that so I'm going to get a big shopping list of spares together to get the best value from the shipping cost.

I got a couple more jobs done on it today.

Firstly was the installation of a dash cam. I do not like having trailing cables anywhere in a car so this was going to be installed with a hidden power supply and no cables visible.

One of China's finest products



This was going to be installed in the dash where it was out of site. Getting the dash apart is dead easy. The complete front bezel just unclips and comes away leaving excelent access to the instrument panel



Four screws and one plug later and I have a large gaping void



The cover on the screen pilar unclips and the tweeter is unplugged leaving access to the wiring loom



The feed for the camera PSU was taken from an ignition powerd cable and a fuse was installed - just in case. The PSU was then tucked down into the dash



Everything was reassembled and the dash cam tested - all working fine!



I'd managed to source all of the fluids required to do an oil change on the front diff, transfer case and rear diff. So, time to get myself and the surrounding area covered in oil!!

First was the front diff. There is a skid plate under the diff that slightly restricts access to the drain and filler plugs



The job can be done without removing the plate but for the sake of the removal of four bolts access can be massively improved



Once drained I measured the quantity of black dishwater that came out - 1.4 litres, it shoud be 2.12 litres. The new fluid was squirted in using a Sealy syringe. Very useful tool and for both removing and refilling oil in differential

www.amazon.co.uk/Sealey-AK46-Suction-Syringe-Metal-Silver/dp/B000RA0XLO/ref=sr_1_9?crid=2N7QZ4BUQ0VLJ&keywords=sealey+syringe&qid=1660862641&sprefix=sealey+syr%2Caps%2C84&sr=8-9

Next was the transfer case. Easy access to both the drain and filler plugs on this one



The fluid in this should be blue in colour (almost like antifreeze) but what came out was a dark brown colour. Either it had the wrong stuff in there or it hadn't been changed in a very long time, if ever. At least it had the correct amount though.

Then we come to the rear axle. Yet another different fluid for this one too, 75-W90 semi synthetic. Up to 2002 Chevrolet fitted a drin plug to the rear diff casing. Mine being a 2004 therefore didn't have one.



So, two ways of draining it: remove the diff cover plate or suck it out with a pump. The cover plate didn't look too clever and I guessed that removing it would result in a damaged gasket.



As I can't just nip to the local autofactor for a gasket I figured that sucking it out using a little electric oil pump I bought from Lidl would be a better option. I have used this pump once before on my daughters Corsa and it worked very well. However, in this case after a couple of seconds of running (before it had even primed itself) it packed up and refused to turn back on. As the diff oil level was correct I figured that for the time being I would leave as is until I either fix the pump or get a cover gasket.

Next was the parking brake. As mentioned previously it had been recorded as barely meeting the MoT requirement. This didn't fill me with confidence as my drive is on a slope so I really needed to do something about it.

It's a dead simple mechanism. Once the brake caliper is removed the disc is slid off to reveal this:



It cant be seen in the picture but that is a single shoe that is clmped oposite to the adjuster. The adjuster is fully manual and all that was needed was a quick clean up and a tweak with a small pry bar to the star wheel.



A couple of trial fits of the disc and operation of the parking brake to ensure the shoes were centered and with a small amount of adjustment each time we have a parking brake that works. The procedure was repeated on the other side.

This is so simple to make work. No auto adjusters to sieze up or complex springs to hold the shoes in like there is on my Mercedes.

So next thing to do will be to order a whole load of parts (maybe even a rear bumper).  I'd also like to add an amplifier to the stereo to power the subs.

It's a nice looking truck, I'm enjoying this thread.

A suggestion for a supplier if you're struggling with sourcing oil etc. Is AAS in Newcastle - they're the main UK royal purple dealer, are really helpful and can source just about any GM fluid - I've used them for bits for my Holden:

www.aas-exhausts.co.uk/