Tremec’s nifty driveline angle app

[HT413]

Just started diagnosing a small driveline vibration I’ve had since installing the new 451. Figured the motor/trans just sits a bit different in the mounts. Figured I’d have to buy a tool, but check out this app I found from Tremec.

They call it Tremec Toolbox. You use your smart phone to measure the angles. The app accesses your phone’s sensors to measure the angles and then calculates the driveline angles for ya. Crazy.

Looks like a quick shim under the tranny mount might do it.

 

[747mopar]

I used it but with little luck, it said mine was good when it wasn't. I downloaded a clinometer app and set mine parallel and solved the issue.

 

[not so famous bob]

I used it but with little luck, it said mine was good when it wasn't. I downloaded a clinometer app and set mine parallel and solved the issue.

what happens when u get on it and the pinion kicks up ?

 

[747mopar]

what happens when u get on it and the pinion kicks up ?

It goes forward really fast or light's the rears up duh.

All kidding aside I'm assuming my leafs being aftermarket and stiffer than stock combined with the fact that I'm running street tires doesn't wrap my leafs like others? It's got over 12,000 reliable miles on it since then.

 

[HT413]

Looks like I got it all sorted out... for the most part. Gotta say, I had no issue with the app at all. After goofing around for a while I finally decided reference off the ends of the u joints and along the driveshaft for my angle measurements.

To do it, i turned the driveshaft so the the pinion and trans yoke were vertical. Then I just set my phone against the ends of the u joints and measured the angles. Had to use a socket against the pinion u joint to get a clear surface.

Once I did that, it became clear that the angles were off. Trans / driveshaft angle was over 5* (max should be 3*) and the pinion was ok at 1.5*.

Decided to shim the trans up a hair to see how that went... 3.7* / 1.2*. Much better but not quite perfect. Took it for a drive and the vibes were MUCH better. Over 70mph I do notice a barely perceptible vibration, so more work to do.

Next trick will be loosening the motor mounts to see if I can get her to settle down a hair.

Before:

After trans mount shim

 

[747mopar]

Damn vibrations can be a lot of fun to sort out. Any idea what could have thrown yours out of whack? I wouldn't think the motor and trans mounts could throw it off very much at all? In my case I'm not certain but fairly confident that my aftermarket springs is what threw mine off (likely me having them de-arched). At least you know your going in the right direction now.

I know when I was dealing with mine I could easily tell what needed done once I got an idea of what was going on because it only vibrated under little to no load (When the pinion was at it's lowest point).

 

[HT413]

I think part of the issue was going from solid to rubber mounts. The solid mount was 1/4” different, so that’s what got me thinking. Now I’m thinking that when I installed the mounts on the motor out of the car maybe they’re set up so the motor sits a hair taller, making the problem even worse.

Not really sure. But like you said, at least I’m in the right direction.

 

[Sweet5ltr]

I think part of the issue was going from solid to rubber mounts. The solid mount was 1/4” different, so that’s what got me thinking. Now I’m thinking that when I installed the mounts on the motor out of the car maybe they’re set up so the motor sits a hair taller, making the problem even worse.

Not really sure. But like you said, at least I’m in the right direction.

I recently went the same direction when installing the low-deck, solid-steel mounts to rubber. No issues. Just throwing this out there, does it matter if the engine is under load, etc. for the vibration to occur? Or is it at the same RPM/MPH every time?

 

[HT413]

It starts at like 70mph or so, regardless of rpm. Not real load dependent and rpm has no effect.

I think the issue is that the *** is squatted down so much, the driveshaft is tipped up toward the rear just a hair. so even a degree over the normal engine rake causes some issues.

I’ll give the mounts a tweak and see. It’s possible the DS got tweaked in the year it sat on my garage floor, but either way I’m gonna replace it soon with something more stout. So that’ll be then next trick