Rear DS up front??

YeloSub7 · 07-02-2008, 08:56 PM

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?

DeathCougar · 07-02-2008, 09:08 PM

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.

YeloSub7 · 07-02-2008, 09:49 PM

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

**Elvota** · 07-02-2008, 10:23 PM

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.

DeathCougar · 07-02-2008, 11:04 PM

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

WFO · 07-03-2008, 05:16 AM

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.

4Crawler · 07-03-2008, 06:22 AM

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.

Wheelingnoob · 07-03-2008, 11:40 AM

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

Blizzard · 07-03-2008, 01:11 PM

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

YeloSub7 · 07-07-2008, 02:45 PM

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...

**Elvota** · 07-07-2008, 02:54 PM

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

4Crawler · 07-07-2008, 03:23 PM

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.

John S. · 07-08-2008, 06:31 PM

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.

4Crawler · 07-08-2008, 06:47 PM

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).

07-02-2008, 08:56 PM	#1 (permalink)
YeloSub7 Contributing Member Join Date: Mar 2005 Location: San Jose, CA Posts: 860	Rear DS up front?? 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? __________________ -Jake 1990 4Runner <> 1990 Toyota 4Runner-22RE-5 speed-TG 3" front/4" rear-33's-4.88's-rear LSD-front TruTrac-MC Rear Bumper-TG DOM Sliders! SAS Build-Up Old Rigs: '85 4Runner (RIP) '95 4Runner (sold)

07-02-2008, 09:49 PM	#3 (permalink)
YeloSub7 Contributing Member Join Date: Mar 2005 Location: San Jose, CA Posts: 860	so this will not work at all? I have heard of many using this setup... __________________ -Jake 1990 4Runner <> 1990 Toyota 4Runner-22RE-5 speed-TG 3" front/4" rear-33's-4.88's-rear LSD-front TruTrac-MC Rear Bumper-TG DOM Sliders! SAS Build-Up Old Rigs: '85 4Runner (RIP) '95 4Runner (sold)

07-02-2008, 10:23 PM	#4 (permalink)
Elvota Super Moderator Staff Join Date: Jun 2005 Location: Phx, AZ Posts: 3,442	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. __________________ ================ 1990 4Runner \| V6 3.4 \| 5spd \| 240 someoddthousand miles \| SR5 \| SAS \| RLS \| 35's \| ARB \| TJM \| 217 to 1 \| W8000 - four wheels \| three sticks \| two hands \| one trail - RIGITY DIGITY

07-03-2008, 06:22 AM	#7 (permalink)
4Crawler Contributing Member Join Date: Jun 2002 Location: SF Bay Area, CA Posts: 6,208	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. __________________ 1985 Toyota 4Runner SR-5, 22REC engine, dual t-cases, 4.88 gears, dual ARBs, 33x10.50 BFGs. r.c.brown@ieee.org TruckEditor@tlca.org Project: 4Crawler 4Crawler OffRoad Gettin'Off 4WD Club Last edited by 4Crawler : 07-03-2008 at 09:09 AM.

07-03-2008, 01:11 PM	#9 (permalink)
Blizzard Registered User Join Date: Jul 2004 Location: Barcelona (Spain) Posts: 871	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 __________________ '94 Toyota 4Runner 3.0 Turbo Diesel Intercooler – Trail-Gear 4'' SAS front, Trail-Gear 5'' rear leaves swap, 35x12.5x15 M/T's and too many things more to write...

07-03-2008, 05:16 AM	#6 (permalink)
WFO Registered User Join Date: Feb 2007 Location: Fredericksburg, VA Posts: 446	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.

07-03-2008, 11:40 AM	#8 (permalink)
Wheelingnoob Registered User Join Date: Feb 2007 Location: Surrey, BC Posts: 194	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

07-07-2008, 02:45 PM	#10 (permalink)
YeloSub7 Contributing Member Join Date: Mar 2005 Location: San Jose, CA Posts: 860	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... __________________ -Jake 1990 4Runner <> 1990 Toyota 4Runner-22RE-5 speed-TG 3" front/4" rear-33's-4.88's-rear LSD-front TruTrac-MC Rear Bumper-TG DOM Sliders! SAS Build-Up Old Rigs: '85 4Runner (RIP) '95 4Runner (sold)

07-07-2008, 02:54 PM	#11 (permalink)
Elvota Super Moderator Staff Join Date: Jun 2005 Location: Phx, AZ Posts: 3,442	I'd say 3"... I think the Marlin site lists how to set up their long slip... might give you the numbers you need. __________________ ================ 1990 4Runner \| V6 3.4 \| 5spd \| 240 someoddthousand miles \| SR5 \| SAS \| RLS \| 35's \| ARB \| TJM \| 217 to 1 \| W8000 - four wheels \| three sticks \| two hands \| one trail - RIGITY DIGITY

07-07-2008, 03:23 PM	#12 (permalink)
4Crawler Contributing Member Join Date: Jun 2002 Location: SF Bay Area, CA Posts: 6,208	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. __________________ 1985 Toyota 4Runner SR-5, 22REC engine, dual t-cases, 4.88 gears, dual ARBs, 33x10.50 BFGs. r.c.brown@ieee.org TruckEditor@tlca.org Project: 4Crawler 4Crawler OffRoad Gettin'Off 4WD Club

07-08-2008, 06:31 PM	#13 (permalink)
John S. Registered User Join Date: Sep 2007 Location: Lafayette, La Posts: 78	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. __________________ 1988 4runner w/ 5'' SAS Trail Gear Kit, 3'' body lift 5.29 with Detroit Lockers, and 35'' Iroks 2002 Chevy Z71 w/ 6'' ProComp stage two suspension, 3''body lift and 37'' SSR http://bslca.com/

07-08-2008, 06:47 PM	#14 (permalink)
4Crawler Contributing Member Join Date: Jun 2002 Location: SF Bay Area, CA Posts: 6,208	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). __________________ 1985 Toyota 4Runner SR-5, 22REC engine, dual t-cases, 4.88 gears, dual ARBs, 33x10.50 BFGs. r.c.brown@ieee.org TruckEditor@tlca.org Project: 4Crawler 4Crawler OffRoad Gettin'Off 4WD Club

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