Helen

Does the locker truly Lock both front and rear axles? How fast can you drive
with one or both locked in the snow?
Thanks

bernie

The 400Q's are nice in that you can choose when/which differentials to lock. There is actually quite a bit of info on this in the owner's manual, you might see if you can get one.

The first position (one notch out on 84, first position to right on 85-87) locks the *center* differential. This makes sure that toe front and rear drives are traveling at the same speed. In real life, since the front and rear diffs are still "open", at least one wheel at each end of the car will drive. When you go to the second position, the system will also lock the rear differential. This now will ensure that both wheels in the rear and one wheel in the front of the car will be driven. Since both rear wheels are going, if you are in low traction, the car will not respond well to steering (understeer), trying to continue in a straight line.

Since locking the front differential would make this tendency to understeer much worse (nearly uncontrollable), Audi does not offer this option.

There are no speed limits to how fast you can go with the diffs locked. The manual recommends not using the rear differential lock above 20 mph or so (don't have my manual in front of me). As a matter of fact, I rarely use my rear diff lock. That mode is useful for plowing through snow above the bumper, or getting unstuck (BTDT). Once moving, if you can tell you will continue moving (not getting re-stuck), you should notch back to the center diff only.

I have used the center diff on the freeway when in a hard rainstorm, dry on the track, and at other times when I wanted to enhance my traction. The only time you will notice a bad effect is when turning tight in a parking lot---the car will "crab" and you will feel the tires fighting each other for traction. This is not a good thing to do, it puts a lot of stress on the drivetrain.

I hope this answers your qiestions. If you have more, feel free to email me. Enjoy your 4kq, they are great cars!

>>>>>Bernie
87 4ktq
99.5 A4 Avant TQMS

Todd W

Drive as fast as you want on snow/dirt/etc. Do not drive at highway speeds on dry pavement with any of them locked. You really don't need to lock them until you get stuck, however it can be fun. I find that center only locked is good on ice. Any setting works in the snow, but the car will handle differently.

Todd W

83 Coupe locking diffs don't work and I don't care
86 5000 removing the locking diffs

ErikR

Excellent answers!

ChuckH

yes, you DO care! :-)

helen

Thank you very much. I have one more question. I thought that the quattro was "full time all wheel drive, with locking diffs", is this true, or is it rear wheel drive untill I turn the dial to the first position?
Thanks again.

ErikR

Full-time AWD (there is no other, just 4x4's [no center diff.]))