Topic: High Pinion or Dual Cases?

[2manytoys]

Getting closer to doing my SAS on my 88 PU. Trying to decide if I should stay with my single case with 4.7's and spend my money on a high pinion, or use a V6 diff I already have and go duals. My main concern is driveline angle issues. Should I even be concerned?

OR........Should I use the diff and single case with 4.7's I already have and put my money into Longs? I can't do all three.

It's my DD but I want a very capable offroader. I plan on running at least 35's, probably 37's. Minimal lift. Chev 63's and RUF.

[yotaneck13]

id say duals although hp would be nice you can always cut an spin the housing if you needed but its a close call since you have 4.7 in your single what gears you got in the axels?

[2manytoys [OP]]

I'm running 4.56's now with Aussie's. I'm going to give my 4.56's to my kid for his 91 and swap in some 5.29's. I'm only running 31" tires right now.

[yotaneck13]

so single with 4.7 and 5:29's youll be at about 95:1 ration i 4low thats pretty slow hp might be a better option in that case

[blackdiamond]

I'd say Longs first, followed by duals and then a high pinion diff.  I had my rear differential rotated and it works great with about 4 inches of lift and 35 inch tires.

Having the high pinion won't necessarily give you the correct angle, just less of an angle when it's aligned properly which will reduce the bearing wear slightly.  It only take a few degrees to get a vibration in a DD.

With the 4.70 gears you have a very capable rig and I'd make sure it's bullet proof before adding more toys.  I do love my duals with 4.70s in the rear, but it's more for the stock low range than the really low gears.  I've found in Moab that low-low 3rd is just about right and oddly enough is just about the same as 4.70 1st.

The reality is that the single 4.70 in 1st gear is just about a pefect gear.  It is slow enough to truly crawl, but still has just a bit of momentum to keep you going.

[2manytoys [OP]]

Thanks for the advice guys.

My 4.7's are great, plus I have a R151F with a pretty low 1st gear. I use 2nd and 3rd a lot, and 1st when I really need to creep.

Blackdiamond, now ya got me wondering if I will need to rotate my diffs. My front axle housing is still bare at the moment while I collect parts. Am I going to have to rotate my knuckles to keep streetable caster? I'm on the freeway a lot @75-80mph.

I'd like to get this right the first time. Not find out my truck isn't safe and have to pull it apart again.

I was leaning more towards Longs and if I get my front axle positioned right maybe a HP won't be necessary.

Keep the advice comming. I need it and appreciate it. Thanks.

[jrock]

Duals! Fixes any drive live angles and if your going to move the front axle, do it now. Your going to have to make new drive shafts anyway.

The first thing I ever did was duals. Best thing I ever did. Lockers f/r comes in a close second.

[blackdiamond]

Duals! Fixes any drive live angles and if your going to move the front axle, do it now. Your going to have to make new drive shafts anyway.  

Duals makes front driveline angle less and the rear more.  I didn't bother correcting the front driveline angle as it really only matters in 4wd and mine seems to work well to about 30 mph.  This is about the limit anyways with automatic lockers on the snow.

Getting the correct driveline angle is necessary for highway driving and you might get lucky enough to end up with something that work, mine wasn't so I had the rear rotated a few degrees.

[Rocksurfer]

Duals will make the front shaft longer and the rear shorter so I don't see an advantage for a DD in fact the reverse. I wouldn't go with the high pinion either since I've seen bearing issues with them when you need to rotate the axle up. Can't go wrong with stronger axle shafts so if you have to spend that $ go with Longs.

[2manytoys [OP]]

Thanks for all the input. Since I already have the V6 diffs and the 4.7's, I think I'm going to go with Longs since I keep hearing the stock birfs will definitely break.

I'm trying to keep lift to a minimum so maybe I'll get lucky with driveline angles. The rear won't be that big a deal to rotate if I have to. The front is what I'm worried about. More for caster than anything. I don't want squirrley handling at highway speeds.

[jrock]

As far as driveline lengths, we're not talking about Jeeps. The 10" out of the rear is not going to cause anything. It will actually help offroad by lifting the driveshaft. And the front driveshaft needs to be longer if you ever want a flexy front suspension or more that 3" lift.

Longs are great but not the best thing you can do. I. Personally would do duals and suspension first. Don't nuke the clutch and keep your wheel on terra firma

[blackdiamond]

The front is what I'm worried about. More for caster than anything. I don't want squirrley handling at highway speeds.

I think as long as you run front springs that were designed by someone and not something you put together in the back yard you shouldn't have any major issues with handling.  You might even get lucky with a DIY set of springs, but I wouldn't expect it.

The push-pull steering is one of the biggest handling factors as it causes bump steer that can be an issue with some rigs.  My 85 had 4-1/2 inch Superlift front springs and it handled great with push-pull steering.  I drove it multiple times cross country.

[2manytoys [OP]]

Well, I was going to do a RUF setup to go with my 63" chevs. Many seem to like this setup. I do plan on installing  high steer too.

Am I going to have to rotate my knuckles at all to keep things good? Will I have to move my steering box? I know.......this thread is morfing into something else. Thanks for all the suggestions.

[GreenYoterKrawler]

Birfields were always my weakpoint, so i say longs then a 4.7 and or duals. I wheel all the time at fordyce and out by folsom lake, and if ur worried about driveline angles, just get shims. Its 20 bucks and toyotas arent heavy enough to break em really. HPs are a waste of money IMO. Ur better off spending the money on larger tires if ur looking for clearance. Ive only hit my rear diff Maybe 5 times out of idk how many trips, & only got stuck once on it i might add.

[Mnmstoy]

Dual cases should of been first in my book. But, I did high steer first...then burnt my clutch up. I then installed my stock dual cases. Never rotated a knuckle and never had any death wobble. It ran great this way with low pinion thirds.
My old set up was 1980 LWB Toyota 20R/W56, 5.29 lockright front. Longfields shafts and hub gear, Hydro assist, dual stock cases, 5.29 welded rear and Drove my truck on the street for about 5 years.
Lift was RUF (5 pack) and 4" alcons in the rear on 36" tires. 
Gas milage was about 16.5 MPG
I'm Running Chevy one tons now on my new set up....but that doesn't apply here.

I Say LONGFIELDS. Great customer service and lifetime warranty regardless if you get them new or used. Don't forget to get the Hub gears to warrent his warranty.
You may have to do some clearance inside the balls of the housing but well worth the down time for a lifetime of stronger axle shafts.

[superyota]

if you have 4.7's already, i would do the longs next.  that is your next week point, and it is a quick way to put a damper on a trip when the stock one breaks, and it will break.  I would go longs first, duals 2nd, and save the money for the hp for something else.

[2manytoys [OP]]

Thanks for all the input. I'm going to go with Long's.

Sounds like the HP is more of a luxury and not a necessity. I may decide to do duals later, but my 4.7's should get me by for a while.

Now I'm researching my RUF mods. Like will I have to move my steering box and will I have to rotate my knuckles? If I can't find the info, I'll be posting up here.

Thanks for all the help!

[awhotrods]

Sounds about right, don't waste your time or money cutting & turning axles.  It is very rare to run into issues with a standard build like yours.  Now if you were sprung under & doing SOA along with a lift you would need to consider it..

if you have 4.7's already, i would do the longs next.  that is your next week point, and it is a quick way to put a damper on a trip when the stock one breaks, and it will break.  I would go longs first, duals 2nd, and save the money for the hp for something else.

[2manytoys [OP]]

quote author=awhotrods link=topic=78200.msg921175#msg921175 date=1298591786]
Sounds about right, don't waste your time or money cutting & turning axles.  It is very rare to run into issues with a standard build like yours.  Now if you were sprung under & doing SOA along with a lift you would need to consider it..

[/quote]

That's what I was hoping to hear!!!

[GreenYoterKrawler]

yeah you only run into problems once you have an about a 7" lift and an L series tranny, then ur front D-line starts to bind. So i swapped in a w56 tranny and some 3* shims. No problems anymore