s2knky

I changed out my broken diff and drivers axle on my 00 ap1 with an 00 ap1 diff and 02 drivers side axle.

The car doesnt make any vibrating out of the ordinary, and I can't hear any sounds out of the ordinary (especially over an intake/header/test pipe/spoon n1)

The car doesn't feel like it's putting all the power down. It's sluggish to get to speed. It won't wind out past 8k.

When I let the clutch out, the engine revs to 9k - so it's something in the driveline.

I lined the prop shaft back up with the hash mark I left on the tranny, however, as it's a different rear diff, I couldn't line the prop shaft back up with anything.

My line of thought is that maybe the drifeshaft is out of balance enough that it's throwing things off ? Did I get a bum diff?

I also changed out the diff fluid and replaced with Castrol 80w90 on the insistance of a mechanic friend. Is this improper fluid a probable cause to this?

I'm not driving the thing until I figure out what might be wrong....

Thanks for any help.

xviper

Sounds like you have some sort of really bad resistance in the driveline. I'm surprised that it isn't vibrating itself off the road and making all sorts of noises. You don't have your ebrake applied, do you?
Is it a GL-5 fluid? If it is, then the fluid wouldn't cause this. If it isn't, it's anyone's guess.

s2knky

yeah - no shimmy or anything. Car accelerates and decelerates smoothly. It's just....slow. And I can't wind it out past 8k. Even at WOT, it just won't go any higher - which almost certainly means it's rotationally related....

Should I drop the prop shaft, spin the diff a notch, and bolt it back up - drive - test - repaeat until it feels right?

SpitfireS

IF you are going to test drive again check for higher temps on driveline parts.
Resistance usually creates heat.

Take the car to a workshop where you can safely raise the car (or the rear) and listen underneath while in gear with engine on.

xviper

I guess it's worth a try but I serious don't think this will solve anything. I've put my diff back onto my car without matching the propshaft marks to the diff flange and likewise with the output shafts and 1/2 shafts. Although this is recommended, unless there is a severe difference in balance of the parts you put on, I doubt this is the cause of your situation.
So, you are saying that it won't go to 9000 rpm in any gear? If you can't do it in 1st gear, this is very odd. You should be able to overpower most kinds of resistance in 1st or break something trying.
are you sure someone didn't swap an AP2 engine while you weren't looking?

s2knky

Good point. Actually, I just notices that the ABS sensor on the drivers side was disconnected (ABS light on). I'm soldering the wires now to reconnect. Might this contribute?

Also - the fluid "Exceeds GL-5 specifications". According to the bottle

s2knky

[QUOTE=xviper,Apr 8 2006, 09:45 AM] I guess it's worth a try but I serious don't think this will solve anything.

Billman250

Changing the driveshaft position (re-bolting in a different position) will definitely not the fix problem.

Turn each wheel, and the driveshaft, in neutral, make sure it all turn freely.

Race Miata

Aren't all year models have the same halfshafts? And aren't left/right halfshafts equal on all year models?

And why did you have to change out the halfshaft? Did it grenade with the diff? What happened? Could anything else be broken as well?

Agree with xviper that if you can't reach 9k in 1st gear, that's A LOT of resistance and I agree with SpitfireS that the resistance would've burnt something given enough time.

s2knky

OK. Update.

I removed the silencer. Adjusted the camber setting on the control arm to match the other side more closely. Took it back out. I can get to 9k in 1st. It still doesn't feel like it's accelerating as well as it did before.

The axle was definitely broken on the driver side. I initially diagnosed it as the diff, and after reassembly discovered the axle to be broken.

(my other diff, doesnt seem like the LSD is working - or it's locked in posi or something)

On the new (installed) diff, the wheels spin freely, opposite directions when turned, driveshaft turns both wheels freely.

1st gear - gets to 9k - feels too slow
2nd gear - gets to 9k - struggle from 8k up
3rd gear - FIGHT to get to 9k
and I didn't have anywhere to wind it out beyond that safely.

Immediately after return I felt the tires - not even warm.
Felt the rear carrier. Warm to the touch - but not anything near what I would call "hot."
felt the CV inner and outeers - ice cold. Brakes - not hot, warm, but not hot.

ABS sensor is still broken driver side. That's all I know of being wrong at the moment.

No CELs - just an ABS light.

I'm stumped.