Hi good people!

My roommate recently had his 87 4runner (22re 4wd) smashed on the side of the road by a motorist driving recklessly at 70mpg. Luckily, he was not in the car! Even more luckily, the frame, axle, and suspension were not damaged. The only mechanical piece that went was the rear driveshaft.



As you can see, it's FUBAR. You might also be able to see the new (old) driveshaft behind him. What we are stumped figuring out is how the telescoping spline works- or rather, attaches (and stays attached).

On his old one (the smashed one), it does telescope. However you cannot separate it into two pieces. The new one came in two pieces, but we can't see how to get it to stick into one piece.

The worry is that it will telescope out too far and come undone, with some kind of catastrophic failure to follow.

Is the driveshaft supposed to be able to pull apart like that? Or does it need to be pressed?

Also another question is alignment at the spline connection. We don't want it to cause any weird vibrations.

Thanks in advance for any guidance!

 

Alignment shouldn't be an issue. I've heard of problems about dshaft vibes due to phasing but I've done a lot and never seen this personally.
The drive shaft should come apart and go together. It may be tough to do because of age and corrosion.

 

Thanks for putting our worries to rest! I figured it would be okay, he's already got it on there. Truck just moved for the first time in a month! Very exciting for both of us!!

Thanks again for the quick reassurance!

 

The splines have to slide. That allows for relative motion between the differential and the transfer case as the suspension springs compress and extend as you go over uneven ground. The drive shaft should be the correct length so when installed the splines slide together most of the way, but not quite all the way. I'm not sure why your old one won't come apart, except perhaps due to the trauma.

Lining up the two ends correctly is very important for smooth operation of the universal joints. The shaft should be assembled so that the universal joint halves that are attached to the drive shaft ends are "in phase". In other words, the "forks" of the u-joint on each end of the shaft should be aligned the same way. It's hard to describe without pictures, and I'm no good at drawing online, but if you google "drive shaft u-joint alignment" I'm sure you'll find a diagram of what I'm trying to say.

 

I totally get what you mean 100% RJR with the alignment thing. That's exactly how he did it, too.

The old busted up one did telescope, it just stopped right at the end of its articulation.

Makes complete sense that it has to telescope to account for changes in suspension height!

 

Just what moved to bend the drive shaft like that??

 

OOF



70mph direct hit from an Impala (truck was thankfully parked and vacant), moved the car 20ft forward where it hit the Kia. Sounded like a bomb went off!

Only "some" body damage to the rear quarter and tailgate. Leaf shackles were damaged but have been fixed & bent brackets rewelded. Axle & frame are fine! The driveshaft took the brunt when the shackles gave way. It was the only part necessary to replace to get it running (besides new tires).

Front end still looks brand new

 

Glad it's working out.

 

Was the person caught ??

Just keep watching things can break after the fact.

After a hit like that!!