help!! in 4 high front tires chirp and get death wobble!

[Marduk49]

so i recently fixed my broke rear pinion by replacing the rear 3rd member, bought a used what i believed was a 4.11 rear 3rd. Installed it with no problems but when i tried 4 high my front tire were chirping like crazy and had a serious what seemed like the infamous death wobble, but i have never experienced it in 4 high and it was not present in 2 high. so i am thinking its was a different gear ratio in the 3rd member that i installed... was hoping somebody might be able to shed some light on the problem.

 

[dargreg]

Yup sonds like higher gwars in the rear alright.

 

[hellbent40]

pull it out and count the teeth and divided it by the teeth on the pinion... will give you the gear ratio...

have a couple of thirds that are stamped on the ring gear 4.11

 

[dgangle]

Prior to pulling and counting teeth on the R&P, did you drive it in 2WD? You should be able to see a considerable difference if you do in fact have a different ratio in the rear diff. DW is totally unrelated to this.

4.11:1 tooth count is 37 ring, 9 pinion
3.70:1 tooth count is 37 ring, 10 pinion

 

[cruiserbrett]

the pseudo DW is cause by the tires trying to turn at different speeds. since the diffs are open the drivetrain is trying to "unload" the binding and tread squirm is about the only way its going to happen. this makes the wheel shake.

Leave the front hubs locked. mark the driveshafts at the bottom. roll vehicle forward in 2wd in a straight line for a few feet, enought to get a few revolutions. note location of marks in relation to rotation. one will have traveled further if the ratio's arent the same.

 

[Marduk49]

so im pretty sure i have the 3.70 10 tooth pinon in my rear after the roll test that Brett suggested, so now the question is which is better to swap out the rear with a 4.11 or swap the front for the 3.70 obviously i have better crawling with the 4.11 but i get better hwy speeds with the 3.70... but i guess from some of you who have more XP than, i what are the pros and cons...

 

[73fj40lc]

Sounds like you already know the pros and cons. It really depends on what the 40 is mostly used for and what you prefer. I have and like the 4.11, but I run 36" iroks so my real gear ratio is really closer to the 3.70.

 

[Mr. Toad]

1. it's easier to replace the rear diff.

2. if you need to do knuckle/birf.work anyway, might as well change the front