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Front drive shaft question

TJ1978

TJ1978

I have MANY questions
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Is this still good do you guys think?
1978 blazer to np203.

I sent pictures to a driveshaft shop and they said that they can build me a replacement front drive shaft. Also, that the shaft appeared to be a custom build.... anyway.

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I would put a known straight edge on it to see if the u joints are in synchronization. Looks to me like the front u joint is a spline or two off with the rear. It is a front and you normally not doing 80 with it engaged. Lot of people have square tube front shafts. Looks like someone lengthened it for the 203.
 
on if the hard parts are good just have a local shop re-tube it and be done with it .

agreed that cut/strech job is funky and the welds even more so .

and looking further the front slip yoke is 90* off from the correct clocking position .
 
You can bet that thing is out of balance, but since you most likely will not be doing anything over 35-MPH in 4X4 drive it would work...not great, but it would work. Along with that custom length driveshaft the u-joints are the factory stock ones. I just changed out the factory stock u-joints in my front driveshaft. I also did some clearance grinding to the double-cardan joint as well while it was apart.
 
sweetk30 said:
on if the hard parts are good just have a local shop re-tube it and be done with it .

agreed that cut/strech job is funky and the welds even more so .

and looking further the front slip yoke is 90* off from the correct clocking position .
Click to expand...

The slip yoke splines are keyed so it can go on only one way...at least that the way my front driveshaft on my Dana-60 is.
 
Just did my front shaft and it for sure wasn't key'd.

And now after hearing this I know it's also out of phase lol. When I took it out they were 45* to each other... So I put it back that way.
 
The thing that sticks out for me besides the crappy stretch job is the yoke on the cv side has a flange like a later 208 or 241 would have. If your 203 uses the style of cv where the yoke only uses straps on the rear u-joint to connect to the t-case this one won't work.
 
It was already hooked up to the 203... Front out put has the flange to connect the drive shaft. I also can switch to the strap style... Ill snap some pics tomorrow.

I ask about the drive shaft, since its a pretty stellar DIY job (hehe). And yes its the front shaft and wont see a lot of action but I think for safety and reliability its best to change it out.

Im sure it will run as is but I have it out and should probably just swap it, depending on what the shop quotes to build a similar drive shaft.
 
shady said:
Just did my front shaft and it for sure wasn't key'd.

And now after hearing this I know it's also out of phase lol. When I took it out they were 45* to each other... So I put it back that way.
Click to expand...

Mine was definitely keyed. It had one spline that was wider than the rest so it could only line up one way and slip on.
 
1-ton said:
Mine was definitely keyed. It had one spline that was wider than the rest so it could only line up one way and slip on.
Click to expand...

Maybe newer, or after market..? :dunno:

Neither one of my front shafts are.
One is stock 81 1-ton, other is ???
 
Spare parts should be able to reliably get you home.
That would be scrap only at my house.
 
shady said:
Maybe newer, or after market..? :dunno:

Neither one of my front shafts are.
One is stock 81 1-ton, other is ???
Click to expand...

Probably because it is newer. The driveshaft I am talking about is in my 1991 V3500 Crew Cab. The driveshaft was definitely the original shaft because the u-joints had that plastic crap in them that I had to melt out when I installed new u-joints.
 
1-ton said:
The slip yoke splines are keyed so it can go on only one way...at least that the way my front driveshaft on my Dana-60 is.
Click to expand...
then they welded the slip and yoke section on 90* off from the correct position .

all fixed yokes on a shaft need to be in the same plane of running from all the stuff i remember and shafts i have seen . if not this will give some BAD vib's
 
Since he also has a "full time 4wd" NP-203,it is important BOTH driveshafts are phased and balanced correctly,since both are spinning and powering the diffs all the time..

If it were a part time T-case you could get by with a hokey front shaft,since it would only see power when in 4wd and going slow..and not turning in 2wd street use..
 
Oh,I hadn't noticed that mentioned before..the above applies to those without the part time conversion kit installed..
 
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