Problems with front driveline angle.

[colbystephens]

Well, I'm getting binding on my front driveline when going up hill or drooping the passenger side. I clearanced it a little and that helped.

Talking about a 5.7/700r4/NP241/Dodge Dana 60, moved 1.5" forward. 5" spring lift.

Would rather not drop my t-case if I can figure it out. Can I run an angled shim up front and avoid death wobble? Would it be reasonable to have a shop rotate my pinion up and weld my axle tubes to the pumpkin?

The bind is happening in the CV. Is it called a double cardigan when you have 2 u-joints at the t-case end of your shaft? Anyway, that's where it's happening. I have a 1350 yoke on my 60. The CV is that S4 or whatever u-joints.

Ideas?

 

[owenst7]

Rotating your pinion won't change anything at the CV.

I hate to say it, but you're either going to need a CV that can handle more angle (like from HAD), or reduce the angle. You could either lower the tcase in relation to the axle, or make the front driveline longer to accomplish that. I think a longer driveline is the beginning to the best solution, as lowering the front suspension isn't going to address the issue under droop anyway.

Have you considered a doubler? That would increase the length of that driveshaft a lot.

I'm really surprised that cv is maxing out with your truck, as it really isn't that tall. How long is that driveshaft approximately?

 

[chevydan3]

I had the same problem with my old truck, Colby. Dropping the t-case will actually rotate the front output up, making the angle worse. Driveline Service on Glendale was able to make me a new shaft with a modified cv for more angle. My whole shaft was around $400, but it was 7-8 years ago. Since your shaft seems to be fine, maybe they can just replace the cv for you, for cheaper. I have also heard something about guys using the front shaft off of late model Super Duty Fords, they supposedly have 1350 cv's.

 

[folkenheath]

Have you measured the angles yet? A standard GM CV can me modified to work up to about 32 degrees, but thats worse case. And that includes droop and spring wrap/wheel hop. I was having the same issue you had with my 6" spring lift. Thats why I rotated my inner C's so I could keep my caster correct and correct my driveshaft angles. Yes, rotating the pinion mostly changes the angle at teh pinion, however, since the pinion is almost a foot long and the front driveshaft is relatively short, it will change the angle at the CV about 30% - 50% of the angle at the pinion. (proportional to the ratio of the pinion length to driveshaft length).

I agree with Dan too, dropping the tcase may help the rear dshaft angle, but it probably won't help the front, may even make it worse.

I think you should start by measureing the angles you have now to see where you sit (including at full droop), and once you have that data you can make a better decision on what the solution needs to be. Caster can be as low as 5 degrees, or maybe 4 at the least for highway handling, so you may have a little room there.

 

[colbystephens]

Rotating your pinion won't change anything at the CV.

I hate to say it, but you're either going to need a CV that can handle more angle (like from HAD), or reduce the angle. You could either lower the tcase in relation to the axle, or make the front driveline longer to accomplish that. I think a longer driveline is the beginning to the best solution, as lowering the front suspension isn't going to address the issue under droop anyway.

Have you considered a doubler? That would increase the length of that driveshaft a lot.

I'm really surprised that cv is maxing out with your truck, as it really isn't that tall. How long is that driveshaft approximately?

I think the shaft angle will change if the pinion is adjusted because the drivelien wouldn't have to drop as much to attach to it.

I'll clearance it a bit more and if that doesn't do it for me, I might contact HAD at that point. The bit of clearancing we did the other night really helped a lot, just not enough.

I've briefly considered a doubler, but I don't have the money for that right now, and don't want to wait on wheelin until I do. I'd really like to do a doubler though...

I don't recall how long the shaft is. I probably won't have a chance to get under the truck again till next week, as I"m out of town starting Wednesday.

I had the same problem with my old truck, Colby. Dropping the t-case will actually rotate the front output up, making the angle worse. Driveline Service on Glendale was able to make me a new shaft with a modified cv for more angle. My whole shaft was around $400, but it was 7-8 years ago. Since your shaft seems to be fine, maybe they can just replace the cv for you, for cheaper. I have also heard something about guys using the front shaft off of late model Super Duty Fords, they supposedly have 1350 cv's.

The guys at Bayshore explained the same thing about dropping the T-Case having the potential to make things worse. They even suggested that I look into raising the t-case if my engine would run at a slightly forward angle.

Have you measured the angles yet? A standard GM CV can me modified to work up to about 32 degrees, but thats worse case. And that includes droop and spring wrap/wheel hop. I was having the same issue you had with my 6" spring lift. Thats why I rotated my inner C's so I could keep my caster correct and correct my driveshaft angles. Yes, rotating the pinion mostly changes the angle at teh pinion, however, since the pinion is almost a foot long and the front driveshaft is relatively short, it will change the angle at the CV about 30% - 50% of the angle at the pinion. (proportional to the ratio of the pinion length to driveshaft length).

I agree with Dan too, dropping the tcase may help the rear dshaft angle, but it probably won't help the front, may even make it worse.

I think you should start by measureing the angles you have now to see where you sit (including at full droop), and once you have that data you can make a better decision on what the solution needs to be. Caster can be as low as 5 degrees, or maybe 4 at the least for highway handling, so you may have a little room there.

I'll get those measurements. Going to be next week before that happens though.

 

[owenst7]

Didn't consider the pinion length changing things.

I have a pair of 6* shims you can try/have. I doubt they're the right angle, but they're yours if they'll work.

 

[imiceman44]

You beat me to it, yes the truning of the pumpkin will help a lot with the angles.


Colby, if your plans for a doubler are still in the distant future, I think your only solution is going to be exactly that.

Have you measured the angles yet? A standard GM CV can me modified to work up to about 32 degrees, but thats worse case. And that includes droop and spring wrap/wheel hop. I was having the same issue you had with my 6" spring lift. Thats why I rotated my inner C's so I could keep my caster correct and correct my driveshaft angles. Yes, rotating the pinion mostly changes the angle at teh pinion, however, since the pinion is almost a foot long and the front driveshaft is relatively short, it will change the angle at the CV about 30% - 50% of the angle at the pinion. (proportional to the ratio of the pinion length to driveshaft length).

I agree with Dan too, dropping the tcase may help the rear dshaft angle, but it probably won't help the front, may even make it worse.

I think you should start by measureing the angles you have now to see where you sit (including at full droop), and once you have that data you can make a better decision on what the solution needs to be. Caster can be as low as 5 degrees, or maybe 4 at the least for highway handling, so you may have a little room there.

 

[colbystephens]

another thing the driveline shop suggested was a clocking ring to clock the t-case down.

Terry, thanks for the offer on the shims.

 

[MTBLAZER89]

Colby you really should be able to make that stock CV work. I run the same setup but with 52's up front. I have a ton of droop and sometimes have issues with my 1310 joint at the pinion, but I clearanced my stock CV and havent had any issues.

 

[colbystephens]

That's really an encouragement. I'm reluctant to go too far with the clearancing of the CV because I'm thinking about what will happen if I overextend those joints under load. Did you just cut the little ears off of the shaft to allow it to flex without hitting the CV against them?

 

[MTBLAZER89]

Yep all those little ears are completely ground down plus a little bit extra. I have exploded one CV, but I blame that on the bad centering ball that I continued to run.

Ya gotta figure most of us run a stock front driveshaft, or at least stock modified for length with 4-6 inches for lift with minimal issues. I prolly have around 5" and 10" of downtravel.

 

[colbystephens]

Ok, I'll get those ears off altogether and see how it does. When thinking about possible failure of the shaft, I'm most concerned about ruining the t-case. Is that a reasonable concern with over binding a driveshaft, or no?

 

[blazinzuk]

There is no one big concern with the driveshaft binding, typically you may explode the CV which can cause collateral damage, sometimes major, low speed stuff like you do it will typically just ruin the driveline. Unfortunately it typically comes apart in an obstacle cause thats where you get flexed out.

I ran a stock style cv with my old blazer and with Horton, it bound a little bit but not much, both of my trucks flex pretty well