I'm doing an automatic to 4 speed conversion on my Century '74. (TH350 to Saginaw 4 speed) When I installed the transmission shaft I seen it was too long. I can't put the transmission shaft on rear axle. I think I don't have the good yoke... Are there several yoke length ? Can I cut my yoke to shorten it ? Thank.
By "transmission shaft" do you actually mean drive shaft? (The shaft that runs from the trans to the rear end)
Do not cut the yoke, it needs to ride in the tranny with play in both directions, because your rear end moves as you drive. You need to measure from the back of the transmission, were the yoke goes in, to the center line of were the rear u joint sits in the rear diff. This needs to be done with full weight on the suspention. Then take your measurements and your drive line to a drive line shop and have it shortend. They should have a good idea about were to cut it.
Are you trying to install the driveshaft with the rear axle hanging down so that the shocks are fully extended? The interference you are experiencing is common when trying to install the driveshaft in this fashion. If you lift the rear axle close so that it is close to the normal ride/drive position there should be no problem. This is also when you would want to measure for driveshaft length. What happens when the axle is hanging down is it actually moves forward forcing the driveshaft farther into the transmission. The TH350 and 4 speed should take the same driveshaft length or within 1/4 inch of each other. Check/double check even triple check before cutting the driveshaft.
Yes ! Transmission shaft means driveshaft, sorry ! To meet to David, yes I'm trying to install the driveshaft with wheels on the floor, (suspension normally compressed). But here it's impossible to mount the driveshaft. I don't need to shorten a lot of, may be just 1/4 inch... I will measure that seriously... Thank you very much, I'll let you know. Adrien.
You need to have the proper length drive shaft. As your suspension moves (like when you go over a hill), the drive shaft slides in and out of the tail shaft. If your shaft is too short it could come out of the transmission, if the shaft is too long it can jamb into the tail shaft and break something. Neither one of these events are worth taking a chance. Russ
Yes ! No problem with that, required for the travel of the suspension, ok. But if the yoke is bearing on the tail shaft I don't understand why I can't cut it. (It's the reason for what I can't install the driveshaft on rear axle...) Look the situation: What do you think about that ?? o No: Thank.
If there is roughly 1" of the yoke machined area for the seal to ride on sticking out of the transmission it is possible there is a problem with the yoke itself. I have seen twisted yokes. Look inside the yoke at the splines to make sure they are straight and not twisted.
Oh yes, I had not thought about condition of the splines ... I'm stupid... I will inspected this ! Thank you.
