I did some searching on this and found alot on front DS's, but nothing on using a rear up front. I have a couple rears from an 83' 4x4 pickup. If I shorten one of these for the front, will it work with my 3" TG SAS kit on my 90' 4runner? Will it have enough slip? The guy at South Bay driveline says it should, having about 1.5" of compression... from what I have read on here about needing a long travel kit up front (that it is a must), I'm a little weary about this setup... Please help!

and I have a low pinion and single case with this setup, with about 31" flange to flange...

If this is not a good idea, then what is the best option? A completely custom ds or is TG's long spline kit work good?

 

Rear driveshafts are non-CV, and with the short length, you need a CV style driveshaft so it doesn't bind.

Find a 79-85 FRONT driveshaft, and have it lengthened. It uses a 30 degree CV.

 

so this will not work at all? I have heard of many using this setup...

 

The joints can be a problem... but it's the slip that's going to stop you.

SAS needs maybe 8" - 10" of DS slip, depending on actual setup. Without it, you'll just pull the DS apart.

 

Didn't say it won't work, just saying its not the best idea.

 

I dont run a CV style up front on mine. Im running a square shaft with standard U-joints at each end. I only use about 3" of slip.

Sure this may not be the most IDEAL setup. But it will definatly work without a problem.

 

Actually u-joints (in a single cardan drive shaft) are less likely to bind than a CV (double cardan) drive shaft for two reasons. First they are shorter in overall length so that results in a slightly less steep angle on the shaft than with a longer CV joint. And a CV joint binds up at less of an angle than a u-joint does.

Now granted, that a CV joint will run smoother at speed (assuming it is set up properly) than a u-joint shaft. But high speed 4WD use is not all that common.

I have my '85 set up for CV shafts front and rear. And with dual cases and my front axle moved forward, I can run my spare drive shaft on the front or rear axle. I had the shaft built with a compressed length of about 33" to handle the front end and with over 12" of slip to allow it to pull out to ~40" for the rear axle.

Note that to run a u-joint shaft up front, you'll need to either re-drill the holes in the t-case flange (for the smaller u-joint bolt pattern) or swap in a different flange.

 

I used the rear shaft out of my 93 4runner in the front (3" TG SAS kit, low pinion and single t case) with a TG 12" slip and used the rear t case flange and put it on the front. I then got my IFS double cardin shaft exstended and used that on the back and took the flange off the front and put in on the back of the T case. Works great, single cardin in the front viberates a bit but its not bad at all.

The double cardin in the rear is smooth as silk.

Jeremy

 

I made a hybrid... Took my front IFS CV shaft, put the TG 12'' spline kit and used it on the front (4'' SAS + HP Diff). The rear is a stock 3rd Gen 4Runner CV DS with the T-Case flange redilled.

David

 

Well in going with the rear up front thing, how much compression do I need? I'd rather the ds drop out than ruining my t case...

 

I'd say 3"... I think the Marlin site lists how to set up their long slip... might give you the numbers you need.

 

Best to measure and see. Measure at rest and then compress the passenger side to the bump stop and re-measure and see how much it compressed. Then estimate how much more it'll compress if the driver's side is also compressed and start with that.

 

I have recently ran into a drive shaft problem myself. Installed the Trail gear 5'' hd SAS kit up front and got the Trail gear Drive shaft welded the CV on and it is not enough angle for my low pinion and single case. Hope one of these ideas help you, I will watch closely to see what works.

 

One other option is to rotate the pinion up:
- http://www.4x4wire.com/toyota/tech/rotated_housing/

Or high pinion diff (less drop = less angle) or use u-joints (shorter and more angle capability) or put in a dual case (longer shaft = less angle).