Changed rear gears, now ABS light is on

I changed the rear gears from the stock 2.92 to 3.43. The car is now way more fun, but the ABS light is now on. I have not reprogrammed the PCM to correct the speedometer. Is the vehicle speed sensor involved in this issue?

Did you use the correct reluctor on the pinion shaft?

Fred Kiehl wrote:

Did you use the correct reluctor on the pinion shaft?

The shop transferred the old one over to the new part.

The ABS light only comes on after about 1 -2 miles of driving. Turn the car off, and the ABS light is off when you restart. Drive 1-2 miles, and it pops back on.

I've never had my foot actually on the pedal when it happens, but I've been told that I might feel pulsing in the pedal or a hard pedal just as the ABS light comes one. To feel that, I'd need to drive the first two miles riding the brake pedal.

The VSS is cheap enough. I may just fire the parts cannon and see if the problem disappears.

The shop should have used the reluctor designed for the new gear ratio. The old one will not work with the new ratio. The VSS is not the problem, save the parts cannon ammo. I believe the correct one has 20 "teeth" https://www.drivetrainspecialists.com/gm/gm-85-chevy/gm-85-342-abs-reluctor-ring.html

As far as I know, if the ABS computer sees too much speed difference between the rear wheels and the fronts, it will light the lamp and disable the system. You don't lose any braking, but do lose the ABS function if that is important to you. The difference doesn't need to be very large, sometimes even oversized tires in the back will trigger it.

Ooooooo, the guy who did the job was not happy to get that news, but to his credit he is going to take the whole mess apart again to replace that little bugger. I bought the gear (thanks for the URL), and I'll bring the car back to him next week when the gear arrives.

We both learned something.

I found it easier to pull the cluster and pull the ABS bulb on mine.

1991BlueBertha wrote:

I found it easier to pull the cluster and pull the ABS bulb on mine.    

I removed mine completely, module and all, and put in a rear proportioning valve. The modules are getting to an age when they are failing, it appears, and I never cared for ABS brakes anyway, or the light rear braking in stock vehicles. I don't drive the Buick in the winter so no end swapping issues with more rear brake. Nice to gain the space under the hood.

I did have to remove the bulb, though, also.

1991BlueBertha wrote:

I found it easier to pull the cluster and pull the ABS bulb on mine.    

Easier yes, but equired for safety inspection in NY, so that's not an option.

dmg4 wrote:

1991BlueBertha wrote:

I found it easier to pull the cluster and pull the ABS bulb on mine.    

Easier yes, but equired for safety inspection in NY, so that's not an option.

The bulb or the ABS?

dmg4 wrote:

1991BlueBertha wrote:

I found it easier to pull the cluster and pull the ABS bulb on mine.    

Easier yes, but equired for safety inspection in NY, so that's not an option.

They require ABS?? I can see them failing a car if a warning lamp is on, but if its not on.....

Glad i live in the land of the free down here. I don't even have to have mine inspected... too old and its registered as antique so its a 5 year tag

If a car is equipped with ABS, it has to work. Sort of like turn signals, wipers, and a catalytic convertor. It's not a freedom thing.

You could put 17% smaller diameter tires on the front (or 17% taller tires on the back) to match the gear ratio change

Good on the shop that is making it right for you - that's just good customer service.

dmg4 wrote:

If a car is equipped with ABS, it has to work.  Sort of like turn signals, wipers, and a catalytic convertor.  It's not a freedom thing.

well i got turn signals, wipers and ..... never mind. LOL


Our state law doesn't require different things for different years.... with the exception of two tail and stop lamps... i think it was prior to 1960 they only require one.... ABS isnt a requirement.... just has to have brakes to stop. Emissions testing on the cars less than 25 years old, how ever, would state that all emissions stuff in place at time of manuf would be required.... but not for these old things....


and yes, land of the free. Free from state inspections on antiques LOL

Fix Until Broke wrote:

You could put 17% smaller diameter tires on the front (or 17% taller tires on the back) to match the gear ratio change

Something like this?