84 Drive Shaft Support Beam

[Thomas F.]

Has anyone removed the drive shaft on an 84 Corvette? I have a question about the support beam that runs along side the drive shaft that connects to the rear of the transmission and the differential. I have replaced the rear seal where the drive shaft connects to the transmission and I am now ready to reinstall the support beam. The Haynes Repair Manual and the GM Service Manual both refer to using sealer around the area where the bolts attach the beam at the transmission and differential, but the manuals do not agree as to how this is done. Can anyone explain what the sealer is for and if it is really necessary? The only reason I can think of is to keep fluids from leaking around the bolts, but there is no leakage of fluid at the differential and it is full of oil. It would seem strange to me if the bolts at the transmission actually went through the area where the transmission fluid is. If this sealer is needed it appears to me it would be almost impossible to apply it 360 degrees around these bolts. These bolts pass completely through the transmission and the differential and have a nut on the top side which is very difficult to access. I had to use a special type wrench to hold the nuts on the top while I turned the bolts from the bottom. Placing sealer around these nuts on the top seems almost impossible. I had to drain the transmission fluid to replace the rear transmission seal, I saw no evidence that any fluid had ever been in the holes where the bolts pass through. Thanks for any comments.

[Jim T.]

Re: 84 Drive Shaft Support Beam

Thomas, I am glad that you have made your post. I have a 1985 and have wondered about the sealer installation mentioned in my 85's GM service manual. One day I may have to replace the drive shaft u-joints.

[Bill B.]

Re: 84 Drive Shaft Support Beam

Thomas, I remember this same issue when I did it on my car almost eight years ago. But, I have already forgotten the reason that I knew back then. I don't remember it having anything to do with "oil leakage" but more with reducing wear or dampening or something of this nature. Know this does not answer your question and hope someone corrects me if way off base--a definitive response this isn't. Bill B

[Edward J.]

Re: 84 Drive Shaft Support Beam

Tom, I have removed many of those support bars in my days at the dealership and cannot remember any type of sealer on those bolts. did you see any sealant on the bolts when you removed them.

I replaced many transmissons in the c4 corvettes as they were problem with the early ones.

[Jim T.]

Re: 84 Drive Shaft Support Beam

Edward what was/is the transmission problem with early C4 Corvettes? My 1985 has just over 100K now with no known problems.

[Edward J.]

Re: 84 Drive Shaft Support Beam

Jim, There were many service bulletins, from internal drum issues, to improper length band apply pins. these lead to forward, direct clutch burn outs. Then theres the Doug Nash over drive units they to had there issues, The gear oil from the 4 speed unit was entering the overdrive units. I wish I had kept all the bulletins they handed me I had 3 ring binders full off them. at some point during the moving process over the years they got tossed out in the rubbish.

If you have not had any issues then something was done right its not like every transmission they made was issue. I believe a lot was a quality control problem these cars where likely rushed through production.

[Thomas F.]

Re: 84 Drive Shaft Support Beam

Edward, the use of a sealant is referenced in both the Haynes Repair Manual and the 1984 GM Shop Manual. In answer to your question...No..I did not see any evidence of any sealer on the bolts or on the mating surfaces when I removed the beam. The 1984 Shop Manual says this sealant is applied only after the beam has been installed. This makes me think this sealer is not designed to prevent any type of leak. Do you think It would be ok to just ignore the sealer and reinstall the beam?

[Edward J.]

Re: 84 Drive Shaft Support Beam

Tom, These bolts had a special plating if I remember correctly to help deal with rust and corosion, they are just through bolts and the most important step make sure the torque is correct. If you are driving the corvette on dry days and not a driver so to speak I don't see any need.The sealer applied after the assy. makes me think water can migrate into the housing and get trapped and cause a problem years down the road.

[Joel A.]

Re: 84 Drive Shaft Support Beam

My understanding for the goop was to help prevent creaking, and other noises from between the tailhousing and the support beam. The tailhousing is kinda hollowed out on the side, so I suppose water and crap could get down in there and create an issue with removing the bolts down the road. On all of the ones I have done, the bolts were corroded anyway, some worse than others. Never had a problem getting any out, tho. All of the goop I have seen on them was a hard, tan colored material...almost like JB Weld in hardness.