Center drive shaft bearing or one piece drive shaft??

[desert-rat]

Has anybody done a one piece drive shaft??

[lutronjim]

Replaced the one in my 70C10 and loved it. I lost count of how many rubber 'bushings' I had to replace for the 3 piece.

[fb111ewo]

When I bought my truck, PO had a one piece drive shaft in it. After I installed a new motor/transmission with the correct motor mounts, the existing driveshaft didn't seem to fit (too short). I ended up having another one piece made by a driveshaft shop. The guy was pretty knowledgeable and said that the driveshaft that I had (brought it in with me) was too small in diameter, and would have definitely caused vibration when driving at higher speeds. The new one is much bigger in diameter and I won't know of issues until I finally get it back on the road.

I think you will find people in this forum that will argue both ways concerning the merits of a one piece vs 2 piece drive shaft.

[Andy4639]

I had 2 piece for many years and had no major problems. I had the 6.0 installed and they cut the 2 piece to short. So they had a 1 piece installed at no cost to me. I have no problem with it and I have a LWB truck.

[MidLifer]

Did a one-piece with my LQ4/4L80e in my LWB. No vibration or noise. Happy with it. I say go for it.

[LS short box]

A good drive shaft shop will ask your max engine rpm and length then determine shaft diameter. Mine is 3.5" diameter.

[Peanut74]

I went to get my drive shaft shortened and made into a one piece. Long story short I'm getting a 3.5" one piece drive shaft made. My question is was does the cross member need to be modified or will it fit in?

[Rich72C10]

hmm, what the benefit of actually going one piece drive shaft (I get you get rid of that carrier bearing)? There has to be a good reason to have a two piece with a LWB, right?

[Jason Banks]

Originally Posted by Peanut74

I went to get my drive shaft shortened and made into a one piece. Long story short I'm getting a 3.5" one piece drive shaft made. My question is was does the cross member need to be modified or will it fit in?

The 3.5" will fit in the hole. Whether or not it hits top or bottom depends on modifications your truck might have.

I have 4/6 lowering with LS 4L80E swap and was hitting the top of the crossmember...

[Keith Seymore]

Originally Posted by Rich72C10

hmm, what the benefit of actually going one piece drive shaft (I get you get rid of that carrier bearing)? There has to be a good reason to have a two piece with a LWB, right?

The concept is to control the driveshaft "critical speed", the point at which it begins to swing like a jump rope. It is affected by length, outside diameter, thickness, material type, mass and rpm. Highest shaft rpm is affected by vehicle top speed, rear axle ratio and tire diameter. Length is affected by wheelbase and driveline configuration.

The driveline is also affected by any unusual or unpredicted system resonances, which can destroy a driveline even at a speed lower than the critical rpm.

From an OE perspective the driveshaft choice (one piece vs two piece) can be manipulated by controlling any one or more of those variables. The trade off is the added cost of the two piece system vs selling a vehicle with a top speed which is lower than desired.

K

[BigBird05]

Keith I love your opinions. Did you make the move to Pontiac? I was there from 97 till I retired in 2002. I worked in the engineering bldg.

[Keith Seymore]

Thank you - I did.

When I came back from the Desert I was at the Tech Center in Warren ever so briefly, and then moved to the white castle on South Blvd.

We were in Pontiac for several years, before they shut down the Truck Validation Center and all of CenterPoint completely and shipped us back to Warren.

K

[AllGoNoShow]

A 4" shaft will also fit in the driveshaft hole for the trailing arm crossmember, if your interested. But, if you go low, you may need to raise the top of the hole to prevent driveshaft interference at max suspension travel (I put up some pictures of what I did on a different thread).

I replaced my one-piece 3.5 driveshaft on my long-bed with a 4" driveshaft when I did a tranny swap-if you look into "critical speeds" of driveshafts, when they get as long as they need to be for a long-bed, you start reaching this critical speed (rpm at which point the driveshaft becomes unstable and starts whipping like a jump rope) of a 3.5" driveshaft around 85MPH depending on specifics of gearing, etc. Jumping up to a 4" driveshaft gives you substantially more RPMs/speed before reaching this point.

[Peanut74]

Thanks for the input guys. I have been getting an education on this matter. I have removed the center bearing carrier bracket since I won't be using it. From what I understand I should be ok since I'm not doing a big drop.

I should have stated that I changed the truck from LWB to SWB and its currently at standard ride height. If I do drop it I will probably do a 2/4 to close up the wheel opening gap.

[BigBird05]

Originally Posted by Keith Seymore

Thank you - I did.

When I came back from the Desert I was at the Tech Center in Warren ever so briefly, and then moved to the white castle on South Blvd.

We were in Pontiac for several years, before they shut down the Truck Validation Center and all of CenterPoint completely and shipped us back to Warren.

K

Ya thats the place. I couldn't remember the name after all of these years. I started at Olds, then transferred to the Truck validation center in 97 till I retired in 02.

[smokeatr23]

I know this is an old post, but do you know the drive shaft diameter and have you had any trouble with it hitting the crossmember? Is yours swingarm rear?

[smokeatr23]

Originally Posted by Andy4639

I had 2 piece for many years and had no major problems. I had the 6.0 installed and they cut the 2 piece to short. So they had a 1 piece installed at no cost to me. I have no problem with it and I have a LWB truck.

I know this is an old post, but do you know the drive shaft diameter and have you had any trouble with it hitting the crossmember? Is yours swingarm rear?