944pilot86

My 86 944 has been sitting for the past 12 months, aside from being started and switching spots several times. I know the odometer worked last time it was on the road last August because I track mileage carefully. Took it for a drive today and noticed immediately neither the trip or odometer were turning. I reset the trip at rest thinking maybe that would unfreeze it. Nothing. I have never reset the trip while moving and have owned the car for 15 years.

Could the odo gear have frozen from sitting, or is it merely a coincidence it decided to give out at this time? Any best steps at this point? I do not want to drive the car until it's fixed to keep the mileage accurate.

bonus12

First post? Welcome to the 944 board.

Well, I know the gear deteriorates over time and is extremely common to break in all 944s if given enough time. The gear turns into a rubbery, flexible, dark tea-colored substance and shears in multiple fracture points, rendering time and space to apparently come to a standstill.
I thought you should still be able to reset the trip?

Anyway, 12 months would be enough time, especially if it decided to bond to the spool or associated gear(s).

Hope that helps, although hopefully someone can confirm whether inability to reset the trip indicates another issue. If I were you I would order a new gear and grab a 6-pack anyway, because once you have the parts off to change the trip equipment, you ought to replace the odo gear.

944pilot86

Thank you! The trip odo did reset correctly to 0000 but still did not turn, nor did the odo. Guess that's what I get for letting it sit..

bonus12

My understanding is that it's a single gear that drives both the trip and the odo. Get the right gear, replace, and you are golden!

No doubt these cars whistle when they get driven frequently.

add: you'll need a 15/16" non-deep socket

No Lag

No Lag

bonus12

Nice pictures. What happens when you order the wrong gear? Does it NOT fit, or does it fit and run at a different ratio? If the latter, I've heard +/- 3%

superloaf

Just did mine and the cheapest seller is fcpeuro. Most places want $25-30 and fcp sells it for $12. And it's a reputable brand that normally sells for the higher price.

I've read that a different gear will change the odometer reading but not sure of the percentage. But i believe in addition there is also a completely different gear on the later cars that doesn't fit earlier cars. Best option is to check your gear before ordering. Or just order both from fcp and you're still ahead of the game.

Oddjob

I had my odo gear fail this July. Pulled out a spare instrument cluster that hasn't been used in years, and the odo gear on that speedo had also deteriorated while sitting in storage.

Also, both my failed gears were the less common 20/22 tooth configuration, not the more common 20/21. So worth counting the teeth before you buy a replacement.

944pilot86

Thanks for the replies.

Finally had the gear replaced by a well known shop in town that all the local Porsche/German Car Indy's send their clusters off to for gear or repair. Tracked my drive home. Google maps said my route was 8.4 miles. My freshly rebuilt trip odo said I drove 8.9.

I'm slightly curious.. did they use the wrong gear, or is a few tenths/half mile just an acceptable discrepancy between google maps, real life and other factors?

Cyberpunky

I just ordered the 20/21 without counting teeth, as I drive my car daily so didn't want to remove cluster twice, and its only a 3% difference, I figure it doesn't really matter much if the wrong one, as car is over 200,000 kM's anyway.

bonus12

It's hard to say. Let's assume your tires are stock diameter. I think all 944s still show a higher speed and a further distance than actual.

Dash01

The reported ~3% difference between the two gear types/ratios means one of them reports ~3% more or less mileage on the odometer than the other.

Which ratio gear reports the lower mileage?

931guru

The one with 21 teeth.