Jump to content

620 rear diff "crab-walking?"


poky_L16

Recommended Posts

Hey guys, I'm Will and I live in SE Idaho about 3 hours from salt lake.

I've had my 72 620 for a few years now and finally decided to lower it. After throwing in 3" blocks and some longer torsion bar bolts, I've got to say, it looks sick! Anyway, I noticed that the overall drive ability of my pickup has gone to complete crap. It tracks all over he road and won't drive straight over 30 mph. A good friend of mine says that it appears my rear axle is "crab walking" and toe'd out to one side when driving under load. I don't really understand how this could happen with a solid rear axle? Is there anyway that this could have happened after lowering it? Any advice/ input would be mucho appreciated. Thanks again.

Link to comment
  • Replies 22
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Also lowering the front increases negative camber and toe in. Top of wheels closer to the body than the bottoms and wheels pointing inward instead of straight ahead. Needs alignment. 

 

When you are done and you notice a low HUMM or vibration, this is because your drive line angles are now way off from the lowering. Usually this can be fixed by placing a 2" spacer under the center bearing bolt down.

  • Like 1
Link to comment

Wow thanks for the fast responses. I used some blocks from the local parts house, oreilly etc. I'm pretty sure I didn't miss the locating pin though. @datzenmike, the front wheels are looking okay, it's the rear that's he problem. I'll try and check my driveshaft angles tomorrow if I can get to a shop.

Link to comment

But if the distance is different then the axle has to be slightly sideways.

 

Measure from the shackle to the axle. If the change was after mounting lowering blocks then one side is not on the leaf spring 'nub'. Just loosen the U bolts and set it straight again.

Link to comment

They are not adjustable.

 

Crabbing is not a normal condition, and is not a maintenance issue (is not caused by wear).

 

The thing to do now is unbolt the spacer and lift the axle up to inspect how the spacer fits right the nub in the spring packs and how it fits into the axle pad.

lowering-block-1.jpg

Link to comment

I respectfully disagree. 31 days this month.

 

I was post dating.

 

 

If the axle turns when accelerating then one side or the other is moving or shifting forward. It must be a huge amount to be noticable. If the wheels turn to the right, check the left side.

 

There should be a 'nub' on the spring pack and another on the top of the block to fit into the axle spring perch.

Link to comment

Just so everyone knows, turns out one of the rear lowering blocks jumped past the top side of the spring bolt, causing the drivers side of the axle to be forward over 1.5"

Got it back in the correct spot and cured everything. Even measurements on both sides now.

  • Like 1
Link to comment

Just so everyone knows, turns out one of the rear lowering blocks jumped past the top side of the spring bolt, causing the drivers side of the axle to be forward over 1.5"

Got it back in the correct spot and cured everything. Even measurements on both sides now.

Hah, called it :). Waited a week to say that :)

  • Like 1
Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.