5mt driveshaft question

THAWA · Post by **THAWA** » Sun May 30, 2004 3:39 pm

What if theoretically someone was unsure if their driveshaft wasn't the correct length. They theoretically could exchange it from the person they bought it from for one of the corect length, but neither of the two people knew which driveshfat to use first, as they werent sure which car it came from. Could one theoretically drive their car without a driveshaft back to the other guys shop and pick it up? Or would something break or get damaged?

NemesisEJ22t · Post by **NemesisEJ22t** » Sun May 30, 2004 6:59 pm

My guess is that it wouldn't be too good for the viscous center differential, but at the very best you would be losing 50% of the engine's power through the lack of the drive shaft for this little trip.

vrg3 · Post by **vrg3** » Mon May 31, 2004 2:23 pm

I remember another board member mentioning limping his car to a shop without its front axles or something. As ciper is fond of pointing out, the center viscous coupling isn't super strong, but you could probably limp at low speed for a short distance without a rear driveshaft.

evolutionmovement · Post by **evolutionmovement** » Mon May 31, 2004 2:35 pm

Tape measure.

Steve

THAWA · Post by **THAWA** » Mon May 31, 2004 2:46 pm

had one been thinking a tape measure would've been an excelent idea, but alas the shaft in question is VERY reminiscent of a 4eat...

THAWA · Post by **THAWA** » Mon May 31, 2004 4:22 pm

while i dont doubt what everyuone is saying, why would it be bad for the visc. coupling to not have another set of wheels to rotate?

BAC5.2 · Post by **BAC5.2** » Mon May 31, 2004 5:02 pm

Imagine the following.

You are splitting the power 50/50 (at the 5MT's do) to each end of the vehicle. The vicious center tries to limit the speed differences between the front and the rear.

No driveshaft means the tranny output at the rear is spinning freely. The Vicious Center Diff sees this spinning, and associates it with wheel slippage in the rear. The fluid heats up and the fronts get more power. It's not long before thermal breakdown takes it's toll and the fluid in the VC starts to sheer. Once that happens, you are putting a lot of power to the rear output, and none to the front.

All you'd be doing after the first few hundred feet is spinning the rear output, and not the front.

If you are in a Jeep, and you blow the rear driveshaft (or front, it doesn't matter), then 4-hi will not operate (4-hi in a Jeep being full-time 4wd. In a Cherokee you could use 4-hi PT [part-time] or 4-Lo to move the truck, but we don't have either of those options in our Suby's). It will spin the rear output because it's the path of least resistance.

If we had a way of locking our trannies in a 50/50 split, and doing away with the VC while in this mode (a mechancial lock, like 4-hi-PT and 4-Lo in the XJ) then we could move the car and only 50% of the power would be making it from the tranny input to the wheels. The other output would spin freely, but the VC wouldn't try to take power away from it, which would cause VC failure.

91White-T · Post by **91White-T** » Mon May 31, 2004 6:24 pm

Isn't the VCD in a 5MT a 50/50 mechanical lock?

BAC5.2 · Post by **BAC5.2** » Mon May 31, 2004 10:25 pm

If it's a VCD, then it's not a mechanical lock. It's a vicious (fluid) lock.

Transfer cases in Jeeps actually have a chain that engages on teeth on the input and output shafts. That is a mechanical lock, all three HAVE to spin at the same RPM.

A vicious coupling uses fluid to control slippage. I am fuzzy on the details of how they work (Vikash?) but I'd imagine it's similar to a torque converter.

rsstiboy · Post by **rsstiboy** » Mon May 31, 2004 10:51 pm

thats exactly why it makes it impossible to dyno our cars on a 2wd dyno!

BAC5.2 · Post by **BAC5.2** » Mon May 31, 2004 11:03 pm

Yep, the only way to run correctly in 2wd would be with a welded center diff, and pull the axles.

evolutionmovement · Post by **evolutionmovement** » Mon May 31, 2004 11:08 pm

I wonder how hard it would be to swap in a 2wd transmission just for dyno tuning. I'm considering getting an ECU for my engine and waiting on the AWD conversion until after I've tuned it as there are no 4-wheel dynos here that I know of.

Steve

free5ty1e · Post by **free5ty1e** » Mon May 31, 2004 11:37 pm

Aren't our cars 40% front/ 60% rear power distribution? I seem to remember reading that somewheres.

Also... couldn't you just put the fuse in for FWD mode to drive without the rear wheels getting power at all? Wouldn't that solve the problem...?

BAC5.2 · Post by **BAC5.2** » Tue Jun 01, 2004 12:00 am

There is no FWD fuse for the 5MT cars, only the 4EAT. With a 5MT tranny, the fuse (if swapping from a 4eat to a 5MT) won't do anything.

5MT Legacy Turbo's are 50/50 with a vicious center diff.

Steve - Wouldn't be that hard I suppose. You've already got the 2wd tranny, just swap the engine, tune, then swap the AWD stuff. I assume you'll be using a Turbo tranny, so you'll have to change the clutch and stuff when you swap the trannies anyway.

THAWA · Post by **THAWA** » Tue Jun 01, 2004 3:41 am

eek more questions. Which side of the clutch goes where? I assume the side that stickes out more goes tword the pressure plate, and the side that is almost flat goes to the flywheel. Is that right?

free5ty1e · Post by **free5ty1e** » Tue Jun 01, 2004 11:08 am

Whoa. My car was always a 5MT, yet it has the FWD fuse. Read in the manual about it - didn't recall seeing it only was for the autos. I was always under the impression I could put my car in FWD mode for service purposes. Thanks for the info.

Where did I get the 40/60 distribution idea from? Are Imprezas 40/60? Now I'm all kinds of confused.

rsstiboy · Post by **rsstiboy** » Tue Jun 01, 2004 11:16 am

sorry, all legacies/liberties are 60/40 split, thats why they have a 3.9 front diff, 1.1 centre stepper and a 3.545 rear diff (3.545 x 1.1 = 3.9), check the sticker on your rear diff if you don't beleive me, I have a 50/50 drivetrain now, because I swapped in a JDM 5MT tranny with 4.111 ratios front and back, its not as much fun now because you have to try REALLY hard to get the rear end out around a corner.

BAC5.2 · Post by **BAC5.2** » Tue Jun 01, 2004 11:24 am

I think only the 2.0L Libertys have the 1.1 center diff, just like the WRX. And the BC6 has a 1:1 center diff with 3.9's at both ends.

THAWA · Post by **THAWA** » Tue Jun 01, 2004 3:46 pm

all us 5mt's except the wrx are 50:50, with a 1:1 ratio.

free5ty1e · Post by **free5ty1e** » Tue Jun 01, 2004 7:14 pm

I'll have to recheck what's on my rear diff sticker, I checked the fluid in it a few weeks back, looked clean, noticed the sticker and didn't really remember what was on it. Now I'm confused. I want 40/60, not 50/50 - for the same reason. I likes to drift.

Are there AWD controllers for our cars that allow that sort of adjustment?

mTk · Post by **mTk** » Tue Jun 01, 2004 11:26 pm

THAWA wrote:eek more questions. Which side of the clutch goes where? I assume the side that stickes out more goes tword the pressure plate, and the side that is almost flat goes to the flywheel. Is that right?

Yep.

MK

mikec · Post by **mikec** » Wed Jun 02, 2004 12:01 am

My sticker says 3.9. No LSD mentioned anywhere

, but hopefully that'll change eventually.

NICO · Post by **NICO** » Wed Jun 02, 2004 8:43 am

thats funny my car says 3.900 with lsd and when i hammer the gas my back end slide out first qwite fun.

BAC5.2 · Post by **BAC5.2** » Wed Jun 02, 2004 9:23 am

free5ty1e wrote:I'll have to recheck what's on my rear diff sticker, I checked the fluid in it a few weeks back, looked clean, noticed the sticker and didn't really remember what was on it. Now I'm confused. I want 40/60, not 50/50 - for the same reason. I likes to drift.

Are there AWD controllers for our cars that allow that sort of adjustment?

A) 50/50 will still drift, it just takes a bit more balls to do it. In the rain, 50/50 will understeer if you peg it and floor it around a turn, then the rears will catch and toss you into a drift.

B) No. The tranny in our cars don't have DCCD (Driver Controlled Center Diff). There's no aftermarket option for this (that I am aware of). The JDM non-DCCD trannies are actually stronger than the DCCD equiped versions. All the more reason for me to stay away from a DCCD.

I wouldn't mind having 40/60, but in the end, I'm pleased with the balance that 50/50 gives. I could probably get the back out on any given turn when pushing the limits of the car, and that's fine with me. I love how I can push the car to its limits without oversteering, and yet with a lift of the throttle, and a tap of the brake, I can get loose in a sideways fury. If you have problems getting the Legacy sideways, then you aren't trying. Lift-throttle oversteer man, or brake induced. I can't oversteer in the rain unless it's under power. I attribute that to the shitty tires though.

rsstiboy · Post by **rsstiboy** » Wed Jun 02, 2004 10:16 am

if you have a 3.9 rear diff you don't have a 1.1 stepper. the front diff is a 3.9 too.

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5mt driveshaft question

5mt driveshaft question