Double Cardan or Wide Angle?
- Thread starter terryjm1
- Start date
Yeah voodoo. How do you think they came up with getting them out of phase on purpose?
I bet they just moved it a spline at a time till it got smooth.
I bet they just moved it a spline at a time till it got smooth.
Quite a few European cars (BMW, Mercedes, Porsche) incorporate rotoflex couplings their rear drivetrain.
There is a denser and beefier rotoflex “doughnut” for a BMW which fits the Disco 2 driveshaft’s bolt hole dimensions. If any one is interested I can search the part number in my Disco 2 cheat sheet and post it here.
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I like the rotoflex coupler. I also don’t lift my trucks very high. The first time I had to change out the rear prop shaft to a U joint I noticed right away the extra noise I was getting thru the drivetrain. A high pitched kind of disturbance is how I would describe it. I wouldn’t have thought much of it if it was a truck I had no experience with. But it was obvious that right after I put the u joint in it I heard it.
But that being said if your truck is lifted 3 inches, the rotoflex will cause a vibration.
I like it, too - more and more.
In my quest to kill the driveline vibration, I replaced the rear (roto'd) driveshaft with U-jointed shaft from BP Utah on a 95 LWB Classic.
It was mind-blowingly amazing - for the first 200 miles. I replaced both U-joints in it in the span of 1000 miles, found that they used either a badly-beat-up or improperly-sized front yoke (so that they had to _shim_ the bearing caps!), it also had bad dings on it which were left untreated (and bent the bearing cap).
Don't know if I'll go back to a Rotoflexed rear driveshaft - but I might.
Compared to that, a U-jointed shaft on a Disco 1 was worth the swap.
The U-joint is the same... so can't one just swap the flange from the D1 over to the D2 (cardan equipped) shaft? That seems the easiest and will be what I try to do
What Terry and I found out was there was an adapter between the flange and the shaft. I have one more. I’ll take a picture of it when I get to my shop this morning
More Voodo is that the rear shaft has cardboard in it on a D2. They were throwing the book at the D2 to quell harmonic noise.
I bought a 1995 D1 years ago with no floors as it was an east coast car and rotten to hell. The drivetrain whining noise was so bad ringing in your ears you had to turn your head sideways to drive the car down the freeway. Harmonics off the rear end and tcase were unbearable.
Angles, it's ALL about the angles! Converting away from the rotoflex and switching to UJ doesn't fix the angles just bandaids the vibrations. You must then get the pinons parallel! I added spacers on rear trailing arms to achieve this. If you can NOT get angles parallel, then a double Cardon is your only option.. Some people I read have DC on the rear as well, as I'm guessing they never tried to level the rear axle with trailing arm spacers.
Remember if your pinion angles don't match or are not parallel your drive shaft will be twisting every revolution! Enough of an angle and your UJs will only last 200 miles.
First, in nearly every 4x4 the driveline is canted a little towards the rear. In the D1/RRC, the rear output of the transfer case is close to be parallel to the rear pinion - in a stock truck. The upper A-arm has shorter distance axle-to-frame than the trailing arms, so with spring lift the pinion is pointing progressively towards the ground (and away from the transfer case). The rear driveshaft is not very long and it is relatively light, so it can absorb the geometry to some extent - and not beyond that. I believe it was a Discoweb collective observation nearly 20 years ago that 80% of trucks lifted up to 2" will not have driveline vibration - and nearly 80% lifted 3"+ will.
The front pinion angle is never parallel to the front output of the transfer case. It is very common to other 4x4s as well, and this is why most front driveshafts have a CV / double Cardan joint. RRC/D1 do not, hence some woodoo RobertF mentioned (45 degrees-phased joints, a massive vibration damper on the bottom of the third member).
I just found that I already made nearly the same post earlier.
Well in my measuring the transfer case is pretty dang level on my D1.. Also after lifting 2" TF medium and converting to a UJ rear shaft my angles were 4 degrees off! Pointed UP.
The reason DC are used up front is to half the UJ angles and even out the twisting of the shaft closer to what a constant velocity shaft can do.
And yeah most the jeeps I've worked on or owned aren't All wheel drive, so the front DS is free spinning or idle and that front shaft angle doesn't mean anything.
I've spent weeks and thousands of parts just getting my Rover to cruise smoothly at 75mph. Most of the Driveshaft stuff and angles I already knew from being an A&P aircraft mechanic. Tom Woods also has some YouTube University videos that really digs deep into Static and Linear driveshaft vibrations.
The reason DC are used up front is to half the UJ angles and even out the twisting of the shaft closer to what a constant velocity shaft can do.
And yeah most the jeeps I've worked on or owned aren't All wheel drive, so the front DS is free spinning or idle and that front shaft angle doesn't mean anything.
I've spent weeks and thousands of parts just getting my Rover to cruise smoothly at 75mph. Most of the Driveshaft stuff and angles I already knew from being an A&P aircraft mechanic. Tom Woods also has some YouTube University videos that really digs deep into Static and Linear driveshaft vibrations.
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It only makes sense in comparison with one or both axle pinions.
I ran into that when I used a pair of Range Rover axles for the Wagoneer. Welded the spring perches parallel to the pinion, just to find out later that the pinion was never intended to be horizontal.
So.... D1..double cardan.. front shaft from a D2... will it blend? or will it fit? Can (or do) I swap the D1 flange [to LT230]? Or can it just bolt up? I am running the stock guibo on the aft end of the rear, btw.
Just swap to a D2 front output flange (CHANGE THE SEAL!) slap in the D2 front Driveshaft and SEND IT!
BUT BE AWARE! The stock D2 DS is known to explode and take out the transmission as well! No Zerks makes it even worse.. So at the VERY least put new UJ's and centering ball in it! You have been warned!
Video demonstrating out of phase drive shafts Twisting.. Mind you it is exacerbated but the other free end would be your wheels turning at 75mph and all the kinetic energy; so the output speed wouldn't change like in the video, rather twist the shaft/UJ's/Gear's lash on and off etc etc. Just "BAD stuff..
Which BTW my stock front DS (with NEW UJ's) was doing with the rear removed and 3 deg Caster Arms putting front pinion near parallel with the Driveshaft.
0-5mph 'power pulsing' like a bad torque converter!
Which BTW my stock front DS (with NEW UJ's) was doing with the rear removed and 3 deg Caster Arms putting front pinion near parallel with the Driveshaft.
0-5mph 'power pulsing' like a bad torque converter!
I bought a Chinese d2dc [new starwars bot?). I've ordered spicers for it. Now I Gotta find that ball and a flange kit.
I replaced the front seal on my old 96d1 and was surprised at how easily it came off. I mean, it wasn't exactly a greasy spoon but it came off without fuss.
If I hadn't spelled it cardigan I'd have spent the extra couple hundred on the Tom Woods part.
How much is your transmission and truck worth?
BUY a TW or GBR... Grease them every oil change and be done with it.
Or run the Chineseium DS and pray it never explodes. I "thought" it was a stock D2 shaft...
I personally would never the china shafts..
Abilit the rear shafts in our conversion kits sold everywhere are probably just that, china shafts!
So YOLO, do what you think is best!
Yeah, after all the chatter on the two or so threads, on this topic.. I sent it back.
I'll drop a stock replacement UJ in my stock propshaft until I can pony up for the TomWoods shaft. Also, I *really* like his use of common u-joints...
Thanks for all the advice!