: front driveshaft spinning question


punkigor
05-16-2005, 11:12 AM
Ok, i know in the ADD tacomas the front cv shafts are always spinning but are only powered when you're in 4x4 (so they're free-spinning the rest of the time). is the front driveshaft always free-spinning too (and powered only when you put on 4x4), or does it only start spinning when you turn on 4x4?

i'm trying to isolate a noise up front and am wondering if it can be from the front driveshaft & u-joint. if they don't spin unless the truck is in 4x4 then they can't be the source of the noise since i'm driving around in 2hi regularly. Thanks

AK98Taco
05-16-2005, 11:22 AM
If you have a V6 truck your t-case is gear driven and the front driveshaft can be disengaged, but I don't know if you can do that with your stock shifter.

Four-cylinder trucks have a chain-driven transfer case and the front driveshaft is always going to be spinning.

ShowStop
05-16-2005, 12:03 PM
Ok, i know in the ADD tacomas the front cv shafts are always spinning but are only powered when you're in 4x4 (so they're free-spinning the rest of the time). is the front driveshaft always free-spinning too (and powered only when you put on 4x4), or does it only start spinning when you turn on 4x4?

i'm trying to isolate a noise up front and am wondering if it can be from the front driveshaft & u-joint. if they don't spin unless the truck is in 4x4 then they can't be the source of the noise since i'm driving around in 2hi regularly. Thanks
Your front driveshaft should not spin if you are not in 4wd and/or if your hubs are unlocked.

ShowStop
05-16-2005, 12:08 PM
If you have a V6 truck your t-case is gear driven and the front driveshaft can be disengaged, but I don't know if you can do that with your stock shifter.

Four-cylinder trucks have a chain-driven transfer case and the front driveshaft is always going to be spinning.
Whoa...you need to get your facts straight. ALL Tacoma transfer cases are chain driven, regardless of engine or transmission type. Also, the front driveshaft should only spin if the transfer is in 4wd or the hubs are locked.

punkigor
05-16-2005, 12:49 PM
Whoa...you need to get your facts straight. ALL Tacoma transfer cases are chain driven, regardless of engine or transmission type. Also, the front driveshaft should only spin if the transfer is in 4wd or the hubs are locked.

what about trucks with Automatic Disconnect? my hubs are always "locked" and the CVs always spin since i have the auto-disconnect, not manual hubs.

ShowStop
05-16-2005, 01:01 PM
what about trucks with Automatic Disconnect? my hubs are always "locked" and the CVs always spin since i have the auto-disconnect, not manual hubs.
Yes, your CVs will always spin, but the ADD will disconnect the passenger side CV inside the diff, so the spider gears in the diff will spin, but thats it.

punkigor
05-16-2005, 02:02 PM
cool. thanks.

AK98Taco
05-16-2005, 04:34 PM
Whoa...you need to get your facts straight. ALL Tacoma transfer cases are chain driven, regardless of engine or transmission type. Also, the front driveshaft should only spin if the transfer is in 4wd or the hubs are locked.

You're right on the chain-drive.

On A.D.D. trucks, it looks like the front output shaft is engaged by a motor and clutch on the driven sprocket. The description of operation is difficult to understand, but I think the 4wd selector on the t-case shifter (if equipped) instructs the actuator to engage the front driveshaft.

I know that on my truck, which does not have the A.D.D. system, boths shafts are always spinning, as only the t-case shifter controls them. All I can do with my twin-stick is move the range shift rail and the 2wd/4wd shift rail, but I cannot disengage the front driveshaft.

ShowStop
05-16-2005, 05:24 PM
On A.D.D. trucks, it looks like the front output shaft is engaged by a motor and clutch on the driven sprocket.
Only on newer models that have the push button 4wd. The older models with the traditional shift lever still had to shift to 4wd.

AK98Taco
05-16-2005, 07:21 PM
The diagram I saw of the shift lever showed the L-N-H positions on the shift knob and the 4wd button on the side of the knob.

not2XS
05-18-2005, 05:20 PM
...I know that on my truck, which does not have the A.D.D. system, boths shafts are always spinning, as only the t-case shifter controls them. All I can do with my twin-stick is move the range shift rail and the 2wd/4wd shift rail, but I cannot disengage the front driveshaft.
I don't know what you have done with your twin-stick, but it seems likely to me that one of the shifters (the 2/4 one) should disconnect the front drivetrain at the t-case (like the t-case originaly could with one stick), and the manual hubs (which you presumably have) should disconnect it at the wheel end. So you should be able to get the front driveshaft free to not spin.

Perhaps you have put together some unusual combination, maybe you formerly had ADD and didn't switch to manual hubs because you twin-sticked it, or perhaps you had a brain-fart and forgot that the t-case could disconnect the front driveshaft.

AK98Taco
05-18-2005, 08:57 PM
Neither. My truck came with manual hubs when I bought it, and I assume it came that way from the factory.

I pulled the transmission and t-case to replace a clutch. At the same time, I installed the twin stick. I modified the range shift rail so that it would not overlap with the 4wd shift rail. I played with the t-case before and after the modification.

Maybe it didn't work right, but that's what it does.

http://www.frontrangeoffroadfab.com/twinstick.htm
http://www.marlincrawler.com/twinshifter.html

NUKE
06-18-2005, 02:14 PM
If you have a V6 truck your t-case is gear driven and the front driveshaft can be disengaged, but I don't know if you can do that with your stock shifter.

Four-cylinder trucks have a chain-driven transfer case and the front driveshaft is always going to be spinning.

Both cases are chain driven and in both instances the driveshaft only spins when in 4WD.