I live in WV and just purchased this vehicle last week. Its so unique, I love driving it! I did some searchs and it seems that the 4000S quattro 5cyl was a Canadian version?

It has the differential switch on the dash to convert to front or front+rear lockup. Thats what it seems like it is? I have read the manual but can't be sure of one thing. Is it OK to switch this on when the vehicle is moving and what speed is it OK to switch this on and off at?

Anyway my question to all you Audi quattro experts is what are the top 5-10 problem areas that I should be concerned with or what 5-10 things I should service or replace on this vehicle before I start putting miles on this car?

Thanks for all your help?

Jeff DeVincent
Morgantown, WV


2002 Audi A4 1.8t quattro
1986 Audi 4000s quattro

 

The diff configuration is thus:

Switch 'off': 3 open diffs, full-time AWD.

Position 1: Front open, center locked.

Position 2: Front open, center locked, rear locked.

From what I've read, you can lock them while the car is moving, they're clutch-actuated, and the quattro system is built to handle massive abuse, but you won't really need to lock them in day-to-day driving.

As far as problems go, electrical problems crop up from time to time, wheel bearings are rather weak, The vacuum pump on the engine tends to go out(I still don't know why it's in there to begin with), the lifters will need to be replaced eventually, and I've heard of the firewall weakening and rupturing where the clutch cylinder is attached. The diff locks are vacuum-operated, too, so vacuum hoses can dry out and crack over time, causing the diffs to lock and stay that way. All in all, though, they're fun, reliable cars that can go almost anywhere without trouble. The engine and driveline are bulletproof, too.

 

I'll answer the quattro part.

First off, your car has full time all-wheel drive in position '0'. This gives you great grip in the rain and MUST be left in that position for wet/dry conditions on the road. Do NOT deviate from that. Technically it is an 'open' differential, meaning any one of the 4 wheels can slip and stay spinning until that wheel regains traction. Torque split is 25% at all 4 wheels.

The '1' can be used in the snow and on gravel. This locks the center differential which binds the front and rear axles together. If it is used on dry/wet pavement you will experience 'axle bind' which can harm the drivetrain eventually (it's a tough car, but has its limitations).

'2' should only be used if you are stuck in deep snow or need to climb some massively steep snowy hill. In addition to the front/rear axles being bound together, this also locks the two rear wheels solid. One bad side effect to this is the rear of the car can slide out sideways, so use 2 carefully.

One note...be SURE to have all 4 tires the same size and diameter. Theoretically you can use slightly different sized tires but ONLY if you never click it over to '1'. If 2 tires are worn, snow performance will be quite bad as the 2 new tires will rotate at a slightly different speed, causing slip. Studless snow tires are a major improvement in the winter!

If you do get to experimenting with the positions, you may have to roll the car back and forth a few times to release the lock, especially on dry pavement. The car's drivetrain is based on a truck, so it's not really gonna harm it, but do it sparingly.

 

the differential switch is actually locks and they are to be used for low traction conditions (snow/ice or heavy rain)
it is ok to engage while the vehicle is in motion, but there are a couple instances where you wouldn't such as when a wheel is spinning like being stuck,you don't want to try and lock the diffs until the tire is stopped. if you have an owners manual read it, it is very informative on how this works. basically 1 is used in most instances, 2 is only used for being really stuck or if you're rally racing it.

1st thing i would do.
oil change with oem filter, good oil and a mid grade 20w50 is what i use, thinner oils may result in lifter tap.

2nd, inspect brakes

3rd, check tranmission + rear dif oil level and or change with proper gl-4 oil.

4th, check the accesory belts

5th, check all hoses

6th, check your timing belt -if cracked do the waterpump too.

7th, check the coolant to make sure it's not the green stuff (bad for audi) maybe a flush and thermostat change?

8th, grease the driveshaft u-joint (supposed to be done every 5000 miles)

9th, run some injector cleaner

10th, check plugs, wires and cap/rotor.


The 4000 quattros are very reliable vehicles if taken care of properly. i'm on my second one and the only two times my quattro has sorta let me down, was when i let the timing wait too long and i broke it a 6000rpm on a onramp, luckily i was able to change it within 45 minutes on the side of the road at that
the only other time was that junk autozone FP failed on me but i did get a free replacement after a 3 mile hike to the nearest store and a lost of cursing.

if you have anymore questions feel free to ask, they are fun cars and relatively cheap to work on if you can do things yourself. and personally out of the 6 audis my family has the 4000's are the easiest to work on.

BTW, 4000 quattros were not all canadian models, they did have us models, it is possible you have a canadian model though.

HTH!
rich
'86 4kq

 

Thanks for all your helpful strategies to keep the 4000 running!

 

I live in Morgantown, WV. Great mountian roads to drive on.

 

A lot of people I know went to WVU, it's a great town, I always loved visiting out there.

 

Ferry Piech was actually going to build it with a permanantly locked center diff, but decided that would make too much tire scrub and get annoying during in-town drives; they didn't mention anything about drivetrain damage, but I'm sure that would accelerate wear on the system. There are some links posted on the forum to that article if anyone wants to check it out. I don't have the url handy but a search should yield some results.

 

when i finally realized what was going on the transmission had slop in it, but i was really hard on that car too. but all in all in put up with hell and kept on going.

they are pretty much bulletproof drivelines, but don't speed shift your quattro gearbox.

and keep good GL-4 gearoil in it, never put gl-5 in one of these.

HTH!
rich
'86 4kq

 

Here's the link to those quattro articles I posted, describing development of the original Coupe including the tech. notes from Dr. Piesch on the locked diff. issue<ul><li><a href="http://www.conleypublishing.com/hays/audiforum/article01.htm">http://www.conleypublishing.com/hays/audiforum/article01.htm</a</li></ul>