Driving Without Prop Shaft

bonestk87

New member
My friend just bought a Syclone. The guy he bought it off of had some front diff. issues. He removed the complete front diff., prop shaft and rigged some cvc shafts so he could still drive it. :tdown: It has been driven at least 5k like this. I read earlier today on a another thread if you drive without the front prop shaft in you could screw up some kind of viscous clutch in the transfer case. Also somehow the guy he bought it from lost the front prop, so he does not have one. Before he goes and buys a gilbert front prop shaft and fixes the front diff. does anyone think the transfer case is screwed or do you think it will be alright??? anyone :2cents: would be great.
 

Captain Morgan

Moderated User
Re: Driving Without Prop Shaft

It could still be alright, the only way to find out is to fix the front diff, replace the CVs and Propshaft and see how it does.
 

stlSY

Truck RamRod
Re: Driving Without Prop Shaft

My Sy had the propshaft removed by the previous owner. Every service bulliten I have seen on the issue indicates the importance of marking the shaft so it can be reinstalled correctly to avoid balancing issues. When I go to replace the propshaft, is there a method for determining proper orientation?
 

tbauer03

TRBOBOX
Re: Driving Without Prop Shaft

i drove mine for a month or 2 without the front shaft in place and all was fine. becarefull about parking on hills though it will roll backwards if you do not set the e-brake. Oh and becareful with the rear tires for somereason the tread goes away fast if your right foot is a little heavy :)
 

crashing_sux

Blow Me?
Re: Driving Without Prop Shaft

I've read the old driving without a propshaft will damage your transfer case and I have to say I think it's bs. Where is the force to damage it coming from? Say I install a set of linelocks on my front brakes, then roast my rear wheels, I can see that doing some damage as I'm holding the front of the transfer case and not allowing it to spin while spinning the rear, causing a differential in speed and toasting the clutches. Now say I drive down the road normally, and power is sent front and rear, the front of the transfer case turns at the same speed as the rear.

Now take the front propshaft out, and drive down the road, the front of the transfer case will still spin the same speed as the rear, there is no resistance to speak of that would prevent it from doing so, so what's causing the damage. I just can't see it, and there are a number of trucks here that have been driven for a while with the propshaft out and had no problems.

I'm not saying I'm right, but if not could someone please explain to me what the issue is because all of the explanations I've seen didn't have much substance behind them, just "I heard somewhere it's bad" type of deal.
 

dgoodhue

BuSTeD 4.3
Re: Driving Without Prop Shaft

Their have been some good long explainations before, the viscous coupling unit is a sealed unit.
 

Flyin Ryan

hated cuz he drives fords
Re: Driving Without Prop Shaft

God.. I hope you can't frag your transfer case from not using a front propshaft because I haven't had one in for about five months :( when I did this I posted and everyone said all would be fine.. I haven't beat on the truck and still have tons of tread left on the rears to prove it... so we'll see since I just got my gilbert shaft from the ups guy yesterday.

Man, that would be some sh!t if I installed ps and boom goes my transfer case! would be my luck so im kinda scared to install the damn shaft now..
 

'JustDreamin'

Dream: 6LV8 Turbo Bravada
Re: Driving Without Prop Shaft

crashing_sux said:
I've read the old driving without a propshaft will damage your transfer case and I have to say I think it's bs. Where is the force to damage it coming from? Say I install a set of linelocks on my front brakes, then roast my rear wheels, I can see that doing some damage as I'm holding the front of the transfer case and not allowing it to spin while spinning the rear, causing a differential in speed and toasting the clutches. Now say I drive down the road normally, and power is sent front and rear, the front of the transfer case turns at the same speed as the rear.

Now take the front propshaft out, and drive down the road, the front of the transfer case will still spin the same speed as the rear, there is no resistance to speak of that would prevent it from doing so, so what's causing the damage. I just can't see it, and there are a number of trucks here that have been driven for a while with the propshaft out and had no problems.

I'm not saying I'm right, but if not could someone please explain to me what the issue is because all of the explanations I've seen didn't have much substance behind them, just "I heard somewhere it's bad" type of deal.


Hey Boss...

1st, I'm gonna go on the record as saying: I don't own a Ty or Sy. Before you completely disregard anything I have to say, please know that I have done a bunch of research on the BW477 transfer case, including surfing here, a couple of astro sites (the AWD Astros & Bravadas use the same TCase). Reason I've done that research is I want to build an AWD 6.0l LSx V8 powered 4 door 2nd Gen Blazer (or Jimmy or Bravada). (You get the picture, right?) In looking at the available AWD transfer cases, the BW4472 seems to be the best choice for me.

Ok, now on to the meat of the matter. Removing the front propshaft runs the risk of doing damage not because there is a force holding the front propshaft flange still. Actually, its the complete opposite. The way the transfer case works is there is a planetary differential in there (basically an open rear end using planetary gears, like you'd find in an automatic transmission or a Lenco). But it doesn't stop there. There is a Viscous Coupling (VC) in there that regulates the speed differential between the front and rear outputs. If you have both axles on the ground, it doesn't have much work to do, just make sure there is minimal difference in speed. If you have one axle with serious wheelspin (or is off the ground, or the driveshaft is removed) ALL of the engines power has to go through the VC to make the truck go. This is why trucks with bad VC's don't move under their own power when you take out the front propshaft (and why they roll real quick). I think Rockland Gear has an exploded view of the transmission. And I know I have a power flow diagram, but since I'm on vacation 2 states away from home, I don't have that here to be able to show.

Is running without a propshaft GOING to kill the VC? I don't know that answer. Sadly, I don't think anybody knows exactly what does kill them. Is it mis-matched tires? How about Towing? Or pushing a snow plow (I've seen a couple of AWD Astro's with plows)? Or running around with no front shaft? Or just bad luck or old age?

So the biggest question is this: Are you willing to spend $1000 ($600 VC plus labor) to replace a part that has no upgrade path and won't make the truck any faster, just so you can make a little smoke? I'd personally rather spend $1000 on a new set of wheels, or a new turbo, or just about anything that'd make a truck run better / faster / look cooler / whatever.

I didn't mean to start a big controversy. I just wanted to highlight the fact that there may be unintended consequences to running with no front propshaft. After all, these aren't just S10s, and they don't have S10 transfer cases.

'Dreamin'
 

Tooky

Serious about performance
Re: Driving Without Prop Shaft

JustDreamin said:
So the biggest question is this: Are you willing to spend $1000 ($600 VC plus labor) to replace a part that has no upgrade path and won't make the truck any faster, just so you can make a little smoke? I'd personally rather spend $1000 on a new set of wheels, or a new turbo, or just about anything that'd make a truck run better / faster / look cooler / whatever.
Dreamin, I respect your opinion and research on the subject. But I feel in the paragraph quoted above, you are simply spreading Fear, Uncertainty, and Doubt on a subject based on nothing but theory. In terms of a logical argument, you're using your threat of costly repairs to help prove your position that the viscous coupling should suffer damage from the front shaft being disconnected. Unfortunately, the cost of repairs has nothing to do with the question of whether or not the viscous coupling suffers damage from RWD-mode.

Throwing figures like $1000 out there is bogus when complete working transfer cases sell for much less than that on SyTy.net all the time. I dont think I've ever seen one sell for $1000 even brand new (and there was literally a brand new one sold on ebay). Name ONE truck that has experienced transfer case failure from doing RWD burnouts. And then even if you can come up with one, realize that there are countless first-hand experiences posted on this board by people who HAVE done RWD burnouts on their SyTy or drove it for months, and experienced no problems. So you'll need at least enough samples to match the amount of people who had no problems, if you really want to prove your case, in my opinion. Since you're the one making the claim the transfer case will suffer damage, the Burden of Proof lies upon you to prove that claim with supporting evidence.

Otherwise, I think it would be more productive to focus less on scaring people over what "should or might happen" and consider more what ACTUALLY DOES HAPPEN. Can we lay this "SyTy Transfer case burnout damage myth" to rest now, until we actually start hearing reports of trucks failing from it? :argue:
 

'JustDreamin'

Dream: 6LV8 Turbo Bravada
Re: Driving Without Prop Shaft

Hey TookyCat....

Not trying to spread fear, just the opposite. I want folks to realize there may be potential risks that aren't obvious. The problem is that most people don't understand exactly how the transfer case works and that its different than most 4x4 transfer cases.

I don't know of anybody with a Sy or Ty who has blown up a VC. I also don't know anybody who has blown one up in an Astro. I do know they fail, but not regularly. Most people that I've seen post about it didn't know the VC had given up until they took out the front shaft for some reason (like trying to diagnose a vibration, or the front propshaft is damaged or whatever) and the truck didn't move.

And you're right, $1000 is probably a bit steep. Probably only $600 to $800, assuming you do the work, and you don't need much else. I know new VC's go for something in the $600 range (I have priced them out).

Used transfer cases seem to go for somewhere between $350 and $600 depending upon how hard you shop around and what salvage yards you're dealing with (car-part.com is a good online listing). But since there isn't a hard and fast way to verify that the VC is good, you might have to buy 2 to get a good one. Its not like you can plug it in and make sure it works, like an alternator.

I personally don't like ebay for auto parts, all the stuff I've bought off of there seemed to be junk. And by the time you cover shipping and such, you don't necessarily come out ahead.

I'm done with this one. Personally, I could care less what you guys do with your trucks. Doesn't affect my pocketbook in the slightest. Please feel free to recommend to anyone that they can drive for 100,000 miles plus in 2wd. Again, won't bother me. When I build my truck, I will be running it with a front shaft at all times, just because AWD is the whole reason I'm building it. I've already got a Z28 that does nice smoke shows, but its tough to get it hooked up, and once I do, I worry about busting rears (GM 7.625" 10 bolts are wonderful things, I've only busted 2 of them and the cars never been to the track).

Anyway, like I said earlier, I'm done.

'Dreamin'
 
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