Dumb 8.8 Explorer Swap Question

[PetroleumJunkie412]

Ok, just a quick question I failed at looking up.

Have a 8.8 out of a 1999 Explorer torn down and prepped for rebuild. Turns out it didn't need to be rebuilt, but I wanted to be sure (machining marks are still on the ring and pinion, was very well cared for).

Read Jims article on the swap, and a few more, but it's much easier to ask.

Jim mentions setting the spring perches at 6 degrees. Wanted to know if this was a universally correct angle, or if I need to adjust that angle depending on the truck. Right now I'm running 1750lb rear springs and a 1" lift shackle on top of factory spring blocks. Driveshaft is being converted to a 1 piece.

 

[Uncle Gump]

I would think that would be a variable based on the truck. It could also be the factory ranger spring perch orientation.

LOL... that doesn't help a damn bit...

Sorry Junkie...

 

[Curious Hound]

Sounds like one of those cases when Bobby would assemble everything loose, point the pinion where it needs to be and tack the perches in place. Then pull it out and finish the welds.

 

[alwaysFlOoReD]

I can't find it on this phone and new forum software....
I have a link to a Dana article on driveshaft angle best practice. It's saved somewhere on site. Remind me and I'll look it up when I get home in a week or so. Basically best is to have the trans centerline and pinion centerline parallel under load and acceleration. So 1 to 2 degrees down and the pinion comes up to parallel when accelerating.
This applies to a basically stock type leafspring suspension. I don't know what happens when you do a 4-link or other type suspension.

 

[Snoranger]

Sounds like one of those cases when Bobby would assemble everything loose, point the pinion where it needs to be and tack the perches in place. Then pull it out and finish the welds.

This, This is best way to do it.

I can't find it on this phone and new forum software....
I have a link to a Dana article on driveshaft angle best practice. It's saved somewhere on site. Remind me and I'll look it up when I get home in a week or so. Basically best is to have the trans centerline and pinion centerline parallel under load and acceleration. So 1 to 2 degrees down and the pinion comes up to parallel when accelerating.
This applies to a basically stock type leafspring suspension. I don't know what happens when you do a 4-link or other type suspension.

I spent years working in a chassis shop as a second job.
It all depends on intended use, rubber/poly bushings, links, etc. Generally, anything for the street was between 1-4 degrees down depending on all the factors.
In this case, 1 or 2 degrees down won’t hurt anything... bushings are very sloppy.
Everywhere I say degrees down, I mean degrees off of perfect. If it’s a double cardan driveshaft, perfect would be 0 degrees of angle on the rear u joint. If it’s single u joints at both ends, perfect would be matching both front and rear u joint angles.

 

[85_Ranger4x4]

Sounds like one of those cases when Bobby would assemble everything loose, point the pinion where it needs to be and tack the perches in place. Then pull it out and finish the welds.

WWBD? (what would bobby do?)

For mine I put the 7.5 on jackstands and got it so the perches were level. Then I measured the pinion angle with an angle finder. Then I basically copied it for the 8.8. I don't know how much they vary for wheelbase but it is a concern, I was close to Jim's 6* IIRC.

 

[Snoranger]

Watch this video, it explains a lot. I use it to help teach the guys at work that want to learn.

 

[alwaysFlOoReD]

Watch this video, it explains a lot. I use it to help teach the guys at work that want to learn.

I wish he would have run the card on the center teeth on the last 2 demonstrations.
My middle name is Thomas and I need proof....

 

[Snoranger]

I wish he would have run the card on the center teeth on the last 2 demonstrations.
My middle name is Thomas and I need proof....

Yeah, that would have been nice. If you watch the tape , you can see the speed change as it spins.

 

[lvwill]

Snoranger has is exactly right.

 

[19Walt93]

If you get it in the ballpark you can use angled shims to adjust as needed.