Im about a week away from getting my car into the shop and im just making sure i have everything covered. So i was wondering if my AT fd driveshaft would fit when the manual tranny went in? if not what would be a good rout to go as far as a drive shaft? Oh ya i dont think it matters but im still going to have the 3.90 rear end.
Thanks in advance
--Arron

 

no you have to get a manual drive shaft. Look on the forum. Contact Fritz Flynn and Rotary Experiment Seven. Fair price is $75-$150 IMO. I got mine for $75 I think. You can get it cheaper if you buy it part of a package (driveline, rearend, etc.)

 

BTW, get the 4.10. If your whole reason for doing the swap is to wake the car up off the line, then why not? In fact, I wish that I had swapped rear ends BEFORE the swap to see what a difference it would have made. I got mine for about $150 used from rotary experiment seven.

 

Thanks!! just wondering whats the difference between the two? is it just the lenth? if so which one is loger?

 

The auto spline drive that goes into the tranny is a lot bigger and the shaft is longer.

Tom

 

sweet thanks again guys

 

pmed ya

 

so if im understanding this correctly, and id like to think i am, the Auto driveshaft slip yoke is a Larger diameter than the 5sp unit. this means i cant slide the Auto ds into the back of the 5sp tranny?

i thought i had an easy solution for the 0.47" difference in length on the 5sp DS...

 

That is correct. Bottom line - Auto driveshaft does not fit a manual transmission.

Later

 

you know... if the U-joints are what i think they are, i could take a torch and disassemble the 2 driveshafts and make a hybrid unit with the Manual DS center section/tube and slip yoke while combining the Auto diff flange on there...

iirc, the caps of the u-joints are held in w/ nylon right?

 

Thought about that too at one time and shrugged it off due to the FD driveshaft having non-replaceable U-joints. Now, not that they can't be taken apart, but they look hard plastic sealed instead of C-clips. Besides, they are a balanced unit.

Later

 

well i think the tube is the part of the driveshaft that needs to be balanced correctly. the ends of the driveshaft arent as important... especially since the ends are "unbalanceable" (by ends, i mean yoke and flange). plus, the ends are supported whereas the tube isnt so, worst case scenario, itd have the jump-rope effect.

but, if one was uncomfortable with doing this and having an unbalanced hybrid DS... a 4x4 truck shop would definitly be able to remedy that problem. also, several automotive related machine shops can either do it or point you in the direction of someone who can. i happened to take a couple supra flywheels to an automotive/truck machine shop and i found out they also build custom driveshafts, retube and repair so they can also balance... ive seen places that can do it, youd just have to look

also, as far as the u-joints being sealed w/ nylon injected in the grooves; once you burn/melt out the nylon, you can use internal circlips to retain the bearing caps. my K5 blazer had the same setup and i swapped u-joints using a couple sockets and a bench vise. if its complicated like my trans am was, itd have the nylon injected on the inner-side of the bearing cap, closer to the cross as opposed to the end of the caps where its visible from the outside. in this case, you end up using U-joints w/ external circlips... theres a solution for everythign

 

So as long as I have the manual drive shaft, I can still use the auto 3.9 rear end when doing the swap?