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Help with this drive line install.

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5akman

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Recently purchased 1988 Blazer 5.7/700r4/208. I pulled the rear driveline as I needed to replace the pinion bearing. While I had it apart, I replaced all the rear axle bearing/seals and added a powertrax no slip locker. When I re-installed the driveline I noticed that the rear yoke didn't have the little retaining lugs on the yoke or the straps. I believe the yoke is non stock as its a unit with 1.06 caps one direction and 1.125 the other direction. Anyway, is it safe to run the drive line like this with no lugs or retaining type features?

Also, the forward end of this drive line is about 2.5" from being fully seated in the back of the 208 tcase, is this ok?

slip joint.jpg

u joint.jpg
 
5akman said:
Recently purchased 1988 Blazer 5.7/700r4/208. I pulled the rear driveline as I needed to replace the pinion bearing. While I had it apart, I replaced all the rear axle bearing/seals and added a powertrax no slip locker. When I re-installed the driveline I noticed that the rear yoke didn't have the little retaining lugs on the yoke or the straps. I believe the yoke is non stock as its a unit with 1.06 caps one direction and 1.125 the other direction. Anyway, is it safe to run the drive line like this with no lugs or retaining type features?

Also, the forward end of this drive line is about 2.5" from being fully seated in the back of the 208 tcase, is this ok?

View attachment 296564

View attachment 296565
Click to expand...
The slip yoke in the 208 tail should be fine.
The yoke is weird for an axle pinion yoke.
Never seen them on axles, usually this yoke requires the inner c clip on the caps to work.
If they don't have it I would not run it like this.
 
Have you ran this axle before?

Wrong yoke, bad pinion bearing, there is a potential correlation there. Since it's not particularly easy to get the crush sleeve set right on reassembly, I wouldn't have high hopes of it being done properly, if the yoke is wrong.
 
That rear pinion yoke is mechanics 3R inside clip and it is standard for your truck.
The driveshaft, and u-joint appear to be 1330, and are not standard on GM vehicles.

If that u-joint doesn't have clips inside on the pinion yoke side, DO NOT run that!

My pinion yoke was damaged when I swapped the 12 bolt under the K5 and it was 1310 series anyway.

So i bought a pinion yoke for the 12 bolt that took a 1330 u-joint outside clip, instead.
It is typically a Ford u-joint.
When I lifted the truck, i needed/wanted driveshafts anyways.
Had Tom Woods build my K5 rear driveshaft shaft with 1330 all the way around since my pinion yoke was 1330 anyways.

1330 and 3R are nearly identical except fot the snap ring retention being inside on 3R and outside on 1330.

You can actually swap the caps between a Spicer 3R onto 2 trunions of a Spicer 1330 and create a conversion 3R/1330 u-joint.
Other brands.. YMMV

Are you sure there aren't C-clips on the caps on the pinion yoke side?
 
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Time for a yoke lesson then! :)

When did GM stop or start using the yokes that retained the caps with the little nubs? My 14SF from the 90's is that style, pretty sure my mid 80's ten bolt was as well. I haven't swapped a ton of ujoints on various years, so I had no clue there were different ones.

If designed for internal snap rings, the yoke will be machined on the inside for the snap rings to sit flat, correct? Pretty easy to spot?
 
dyeager535 said:
Time for a yoke lesson then! :)

When did GM stop or start using the yokes that retained the caps with the little nubs? My 14SF from the 90's is that style, pretty sure my mid 80's ten bolt was as well. I haven't swapped a ton of ujoints on various years, so I had no clue there were different ones.

If designed for internal snap rings, the yoke will be machined on the inside for the snap rings to sit flat, correct? Pretty easy to spot?
Click to expand...
Yep.
GM actually glued 3R u-joints into place by injecting the glue.
That is why stock Blazer shafts with 3R u-joints don't have inside clips.
But almost everything they made was still machined for inside clips to facilitate u-joint replacement after the factory glued u-joint died.
Only a few double cardan driveshafts that went into Cadillacs had 3R H-yokes at the cv's that were not machined for replacement u-joints.. when those failed, you threw them away.

And the pinion yoke depicted by the op is most certainly a 3R yoke.
Machined for inside clips.
As long as it has those clips just behind the straps there.. he is golden.

A closer picture inside would be nice.

By the way, you appear to have damaged the end yoke of the driveshaft at some point with too steep an angle.
I see witness marks where the pinion yoke bound up against the end yoke.
 
Wow, lots of good info within this thread! I bought the blazer from the original owner, who is a 74 yr old co worker of mine. Its been bone stock since day one with the exception of a rebuilt 700r4 about 17,000 miles ago and a label on the rear shaft from a local drive line company indicating that its been worked over. I wonder if the noted (K5wrench) damage to the yoke is from that yoke maybe being installed on a prior driveshaft as the rig has never had a lift kit on it.

So, I need to see if inboard of the straps, there is a groove on the u joint/cap for an inside clip?

Just looked at the box the u joint came in, its a Neapco 1-5349 which was what was recommended by one of the online after market drive line companies. https://www.drivetrainamerica.com/neapco-1-5349-1310-1330-u-joint-ford-special/ I don't know that I see a groove for an inside clip on this joint. If this is incorrect, what u joint do I need for this apparent bastard situation! :)
 
Neapco 5349 is a 1310 to 1330 conversion u joint.
Now someone may have swapped the caps of that conversion ujoint to have inside clips on the pinion yoke side.
I can't see in your picture.
IF they have, all is well.
If not..

DO NOT DRIVE THAT BLAZER.

You need to replace the rear ujoint of the driveshaft with a different u-joint.

More pictures please.
 
Here are some more pics.

If I were to buy a u joint with the correct sized caps with inside rings and outside cap diameter, could I slip those caps onto this joint? I hit up Napa, AZ, Pepboys and a 4wd shop and no one could help me with the u joint I needed with two different widths and two different sized caps. Perhaps a cap change will solve my issue?

1.jpg

2.jpg

3.jpg

4.jpg
 
Yeah.
You have a 1330 outside clip ujoint stuffed into a 3r inside clip pinion yoke.

DO NOT DRIVE.

Probably why the pinion bearing went south in the first place.

Swapping caps was easy for us because we had plenty of Solid Spicer u joints on hand at Driveline Service San Jose.

You need;
A conversion u-joint 1310 TO 3R.

Call Tom Woods Driveshaft.

If it were me; I'd just put a stock 3R Blazer driveshaft back in there.
 
So my drive shaft is not stock then? Will a stock 3r drive shaft work with the yoke I currently have or would I have to change that also?
 
Yep, your current driveshaft is a bastard.
You have no lift.
Stock shaft would work fine.
Call Tom Woods Driveshaft.
Explain what you have;
3R pinion yoke.
NP 208 t -case slip.
Measure from pinion yoke to t-case seal on level ground.
Give them that info.

Other option is junkyard.

You don't want to screw around with conversion u joints.
Just fix it right now.
 
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I'll try woods and check the local wrecking yard. What year blazers would have this identical shaft?
 
80's.
But the proper way is to identify the slip yoke, pinion yoke, and measure from center of rear u-joint to seal on t-case.
 
My son picked up a conversion u joint yesterday from E.O. Fabrication here in town. If it does the trick, I'm set. If not, I'll be back in touch!! :) Thanks for checking.
 
dyeager535 said:
Have you ran this axle before?

Wrong yoke, bad pinion bearing, there is a potential correlation there. Since it's not particularly easy to get the crush sleeve set right on reassembly, I wouldn't have high hopes of it being done properly, if the yoke is wrong.
Click to expand...
I'm getting a crush sleeve eliminator. YouTube Ally cat customs. Michael has a great demonstration.
 
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