I’ve got a 1977 Trans Am now with a 4L70E transmission that needs a new driveshaft. Has anyone here replaced one - if so did you buy it from any of the online companies or just have it custom built by a local shop?

 

All good drive shaft shops will want to know engine hp levels, max engine rpm and over all length. I haven't ordered one online but many do.
Good time to upgrade to 1350 u-joints.

 

specs are below. Thanks - I’ll make sure to get the 1350 U Joints while I’m at it.

 

My diff cover also is leaking and I’m also thinking of going more aggressive on the gearing. Currently have 3.08s with the 4L70E transmission. Any recommendations on the gears too? It’s got a 285 Continental ExtremeComtact Sports on the rear now.

 

A Series 1350 yoke and u-joint are big hunks of metal usually meant for large truck drive shafts. Test fit one each to see if it will fit your tunnel BEFORE you weld these onto a drive shaft.

Rick

 

Should I replace the pinion yoke while I’m at it? It looks like the 1350 yoke will fit. I can avoid needing a conversion joint correct if I replace the pinion yoke?

 

I do both on LS swaps. I can't speak to clearance issue on your fbody but my 80 fbody has zero clearance problems. The 80 is lowered about 1.5 inches.
I don't do the chrome moly just forged.
My current 80 Camaro project with a LS3/4L60E combo I'm running 3.73's. 275/40 18" rear tires. Tachs about 1700-1800 at 60mph.
Don't know if this helps but I supply the trans yoke to the drive shaft shop. You can buy the pinion yoke from places like Summit.
I use a shop in Waite Park MN. I know they do mail order. Your above price seems high for a steel drive shaft.
Oh and the drive shaft shop is going want to know your engine rpm.

 

Thanks those are similar specs to mine. Have 3.08s in it now but I have 3.73s waiting to be installed. My tires are 285/40/17s in the rear.

I’m still debating if I need to replace the driveshaft or if I just replace the transmission output shaft seal that’s leaking (and/or add a 1350 transmission yoke to the stock shaft). Going to get a 2nd opinion on the driveshaft.

Any concerns about just replacing that transmission yoke? Will that throw my stock driveshaft out of balance? I’ve never replaced a driveshaft or yoke before though the pinion seal was actually just replaced 2 months ago.