Driveshaft won't fully engage over mainshaft!!
04-25-2016, 06:22 PM
#1
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Driveshaft won't fully engage over mainshaft!! The car is a 1993 Z28 LT1. I was almost wrapped up with my auto to manual conversion when a hit a snag trying to install an LS1 aluminum driveshaft through the T56's tail housing. The driveshaft engages the mainshaft smoothly and slides about 1.5 inches up the until it hits a "wall" or some blockage, leaving the shiny slip yoke partially exposed. I also tried my stock LT1 driveshaft with no luck.
I spent a few hours researching this issue and it seems that the driveshaft should be at least engaged about 2.5 inches over the mainshaft.
I bought this transmission used so there's no before and after install comparison or any way I can further pinpoint the issue without ripping off the tail housing. Shaft play seems good, no visible signs of damage to the transmission. The transmission also shifts into gear ok. When I had the driveshaft partially installed I was able to spin the assembly with no problem.
It's hard to see in the housing but I'm thinking the tail shaft housing bushing may have possibly shifted or been damaged. Does the bushing sit about 1.5 inches in the tail shaft housing?
Would a damaged spline or air pressure in the case cause this issue? Is it ever ok to use a rubber mallet to tap the driveshaft in? I'm trying to brainstorm here but I'm thinking my only option is to crack the tranny open tomorrow morning
Thanks in advance for your help.
I spent a few hours researching this issue and it seems that the driveshaft should be at least engaged about 2.5 inches over the mainshaft.
I bought this transmission used so there's no before and after install comparison or any way I can further pinpoint the issue without ripping off the tail housing. Shaft play seems good, no visible signs of damage to the transmission. The transmission also shifts into gear ok. When I had the driveshaft partially installed I was able to spin the assembly with no problem.
It's hard to see in the housing but I'm thinking the tail shaft housing bushing may have possibly shifted or been damaged. Does the bushing sit about 1.5 inches in the tail shaft housing?
Would a damaged spline or air pressure in the case cause this issue? Is it ever ok to use a rubber mallet to tap the driveshaft in? I'm trying to brainstorm here but I'm thinking my only option is to crack the tranny open tomorrow morning
Thanks in advance for your help.
04-28-2016, 08:23 PM
#2
Borrow a known-good driveline from a running GM vehicle with 27 spline output. Try that in the trans.
If not, lower the back of the trans. only, and eyeball the splines with light.
Then, pull it, yank the extension housing and determine if the yoke will enter the bushing. Also, determine if it will engage the mainshaft splines fully.
Incorrect bushing installation, twisted splines, bent mainshaft, burrs on splines that need cleared off, are all possibilities.
If not, lower the back of the trans. only, and eyeball the splines with light.
Then, pull it, yank the extension housing and determine if the yoke will enter the bushing. Also, determine if it will engage the mainshaft splines fully.
Incorrect bushing installation, twisted splines, bent mainshaft, burrs on splines that need cleared off, are all possibilities.
