doubler length, driveshaft angle

[Big Slim]

i think i might run into a drivetrain length issue with all the parts i have. i have a zf5 trans which i believe adds a few inches over stock length. i have a strongbox doubler that is about 6.5" long. the truck has a 5.5" lift and standard 9" rear end. I'm guessing that the driveshaft angle will be too much. has anyone tried this setup? my thought is to not use the doubler.

 

[Apogee]

It's the 5.5" suspension lift plus 6.5" long doubler that are going to be the killers. You could either lose the doubler or build a Hi-9 and keep it. Given the build specs, would I be correct to assume an AZ rock wheeler?

 

[Big Slim]

well, not exactly. these parts all came with the purchase. thou i did really want the 5spd. my last one had 3.5 lift i was happy with.

 

[Apogee]

well, not exactly. these parts all came with the purchase. thou i did really want the 5spd. my last one had 3.5 lift i was happy with.

Ah...so new rig to you, congrats! How do you intend to build and use the rig? That would determine how hard I'd be willing to work towards using what you have versus selling/trading it for what you want.

 

[Big Slim]

right. Not planning on extreme rock crawling trails. i don't really see me needing it with the zf5's low first and low gear transfer case. thou if its there when i do need it... I'm thinking it might effect the cross member design, not just drive shaft lengths and angle, depending if its used or not.

 

[garberz]

right. Not planning on extreme rock crawling trails. i don't really see me needing it with the zf5's low first and low gear transfer case. thou if its there when i do need it... I'm thinking it might effect the cross member design, not just drive shaft lengths and angle, depending if its used or not.

If you don’t use the doubler, then you’ll have to buy an adapter for the ZF to your transfercase. You might want to put that money towards a Hi-9, and not have to worry about driveline angles.

Mark

 

[79INA69]

My set up has a short rear driveshaft of approx 23" on a double cardigan. I have 8" from the top of the axle tube to the bottom of the frame rail. When I started mocking up the the rear had close to a 5.5 lift and it was comical with a LP 9" staring at the transfer case output. Had to lower the transfer case down and get the ride height way down. Decided against the HP9" for cost and proprietary parts reasons/ reliability. Ended up with 14b with a 15 degree angle. Sounds like this would be way more trouble than your looking for to me. Sell the parts you have/ save for another build. Get a 205 case with 3.0 gears or an Atlas to the ZF5. ZF5 doesn't just bolt up either without a little massage here and there.

 

[Apogee]

My set up has a short rear driveshaft of approx 23" on a double cardigan.

Show us a double cardigan!...it sounds like quite the fashion statement.

 

[nvrstuk]

I ran doublers for 20 yrs with a ZF/203 or Klune/D20's for a dozen years. Then a 4r/Klune/Atlas or 205 till this past spring.

The 5.5" lift kills everything. Trash it as you don't want it for wheeling, raises COG too high . Uneeded except for mall crawlers.

So IMO, you will like the benefit of a doubler 100X more than a 5.5" lift. So if you do, here's what you can do and your drivetrain is good for 100K miles.

ZF/doubler/D20 but you really should go 205 as the D20 won't last long as it can't handle the input of 2.7X more torque... you will go thru parts if you have tall tires, lockers and good traction as all those add up to huge amounts of torque, much more torque than a D20 was ever designed for with 28" tires, clutch lockers and about 29:1 crawl ratio.

My recommendation is this setup. ZF/your doubler/205. Great gear selections for all kinds of terrain. Sand, rocks, snow, slow OR fast- not one or the other like an Atlas 4.3 where you get one gear selection.

The ZF/doubler/205 will give you a full 14" of suspension, not just articulation with a 22" driveshaft.

No need for a TruHi9. I ran a (several) Hi9's later but un-needed for this setup.

No ujoint issues or pre-mature wear in 50K miles (at least). Northern buddy still running this setup and he's got to be pushing 70K or more since 1998.

You'll love the combo- ditch the 5.5" lift and you'll like the option.

 

[Big Slim]

so will the 3.5" lift work with that setup?

 

[nvrstuk]

Yes, if you get pinion angles, t-case angles done right.

Probably 125,000 miles btw the 2 of us and we wheel stuff that allows full susp travel.

 

[Big Slim]

so i ended up putting a 2.5" lift on it, and has the 2" BL. looks like if i use the doubler i might be around 24" rear drive shaft.

man i cant decide to use it or not. its cool for sure. but probably not doing that type of off road. shifting the weight of the transfer case might add more stress to the trans/ trans mount. along with the shorter rear shaft. nice to have if ever needed.

on the other hand without it the front and rear drive shafts are pretty similar lengths. less fab to be done mounting another shifter. weight is closer to the trans mount. and might be able to sell it. with the zf low first and just dana 20 would already have a low crawl speed. since its a bronco its worth money and a doubler probably doesnt add much value to it.

trying to make a decision soon as i need a drive shaft to get it closer to being on the road.

 

[nvrstuk]

Here's my take that most people don't understand what a doubler can really do for your rig. It's not just to go super, super slow.

The 2 different doublers that I ran for over 22 yrs were most beneficial when allowing me to wheel in sand or snow. The doublers allow the use of gears for street, relatively high speed wheel speed and rpm (for power)for snow & sand dunes and you can double them up for those few times you need super low speed crawling gears.

I can't think of a single reason for 5.5" of lift unless you like muddin'. Maybe there is but I can't think of one. You'll be glad it's gone. 24" of driveline was 3" more than my buddy and I ran for over 12 yrs.

If you ditch the un-needed lift you get all the benefits of a doubler which gives you the flexibility to wheel in any situation with all the advantages you need.

The ZF/doubler/t-case fits great, no driveline angle issue, tons of gear options for all types of wheeling.

 

[ngsd]

I am about to lower mine as well. 5.5 is not needed and I want to keep the doubler. It has a NP435 D20 Klune V and it is looow. Nice set up but drives terrible with that lift.