[Cruiserdude.com]

Been awhile since I have posted... I am usually offering stupid advice, not asking for it.
The culprit is my 2005 PT with a 5-speed.
Background - this is most likely the most abused PT on the highway, as I am in semi-tractor driveaway services and tow this car behind tractors to delivery - hop in the PT and go to the next job.
After logging over two million miles in these things, I have been up against most issues more than once and do the lion's share of my own repairs and overhaul.

As such, this PT has logged 450,000 rolling miles and 210,000 under power. This is PT #5 for me.
BUT, this one has a pretty wild shimmy that exhibits itself ONLY on harder acceleration and around 45 through 60. Brake rotors are new and fine - no hot spots. Recently replaced both front axle bearings - all seems well and torqued properly. Front to back tire change? I discounted tires as these were rotated and balanced about 2 thousand miles ago. Seems to have been gradually occurring, so...

I changed out the CV axles last year but I am tending to blame the axles again or bearings in the trans. I have another trans in my shop. The weight of the car with me, the equipment and a tank of gas is right at 5 thousand pounds.

Ideas?

the steel I built and carry... and a typical hookup to tow the PT...

 

[chuzz]

Have you ever replaced the lower control arms? The large bushing UNDER the car is a well known wear problem. It's cheaper and easier to to replace the whole LCA as an assembly IF that's where the problem lies. You can get the MOOG assembly from rockauto for a decent price, if you need them.

 

[ImperialCrown]

Shimmy on acceleration can be caused by an inner CV axle joint. Sometimes it can feel like an 'up/down' shake instead of a side-to-side shake.
The right inner axle is the worst offender as it is about an inch or so away from the catalytic converter. After a few years, the CV grease can cook down into a varnish.

Car Vibration When Accelerating: Suspect Your CV Joint

The cause of car vibrations can be difficult to pinpoint because of the vast number of potential causes. But if your car vibrates only when accelerating, you may have a CV joint issue. Address it and you won't be afraid to drive your car again.

axleaddict.com

Bearings may roar, but usually won't cause a shake.
Separation of lower control arm bushings can weaken dampening & rigidity and 'amplify' a shake.

 

[Cruiserdude.com]

Chuzz, Imperial, thank you for the responses... I have changed out the entire lower control arms when I pressed new bearings into the spindles recently. As I said before, I am tending to blame the CV half shafts and will go that route for now... have a set on the shelf. Ha! Car has original struts and it is a good excuse to change those, too. Thanks, Guys

 

[Cruiserdude.com]

PS> I beat the crap out of those lower control arm bushings and have sets in the shop all the time. Imagine if you were being yanked around by a semi on these crappy highways today...

 

[MillennialMopar]

My first car was a Silver PT with a 5 speed. Learned to drive stick in it. Regret trading it to get my truck but a necessary loss. Used to take the back seat out and...well...nevermind.

Good luck getting the culprit fixed, if I ever see a PT behind a Tractor I'll give you a wave.

 

[chuzz]

Well, since you already replaced the LCA's, I'd have to concur with Walt about the axles. I don't think the struts would cause that, but if they're original, replacing them sure won't hurt any. Except your wallet. 😁

 

[KOG]

I'm also going for axles. That seems remarkably heavy for a PT. My 09 T&C Limited 4.0 is 4900lbs with a full tank. And I thought that was outrageous.

 

[Cruiserdude.com]

KOG - the real thing contributing to the weight is the steel, tools and chains that are needed in my driveaway business.
The picture above shows what is in the PT at all times + the steel hitch that is in front. I cut the frame off at the crossover plate and mounted C channel steel, multiple grade 8 bolts to the frame and then the front frame for the v hitch. If I hit anyone, I WILL hurt them. Ha! A semi-tractor side-swiped my previous PT and totaled the car - but I drive it home... the tractor, however, caught the front hitch and wiped out both outer dual tires and massacred the rimes - had to be towed. If you look closely, the hitch is still there and I used again on my present car. I saved the engine, tranny and lots of other things which have come in handy.

 

[chuzz]

What did those wheels come off of? I've never seen any like that on a PT.

 

[KOG]

KOG - the real thing contributing to the weight is the steel, tools and chains that are needed in my driveaway business.
The picture above shows what is in the PT at all times + the steel hitch that is in front. I cut the frame off at the crossover plate and mounted C channel steel, multiple grade 8 bolts to the frame and then the front frame for the v hitch. If I hit anyone, I WILL hurt them. Ha! A semi-tractor side-swiped my previous PT and totaled the car - but I drive it home... the tractor, however, caught the front hitch and wiped out both outer dual tires and massacred the rimes - had to be towed. If you look closely, the hitch is still there and I used again on my present car. I saved the engine, tranny and lots of other things which have come in handy. View attachment 93277
Ah, a loaded weight. Most people just list a supposed curb weight. 5000lbs is still getting up there for a PT.

 

[valiant67]

What did those wheels come off of? I've never seen any like that on a PT.

Dodge Neon, towards the end of the second generation

 

[Cruiserdude.com]

What did those wheels come off of? I've never seen any like that on a PT.

Dodge Neon - Snowflake aluminum... one inch smaller tires than factory. Keeps you within the law on the speedo. ha.

 

[Cruiserdude.com]

Imperial - Chuzz...
Yup it was what we suspected - inside passenger CV half shalt.
Thanks for the discussion.

 

[chuzz]

It's all good, man. Now, drive it like you stole it! LOL

 

[dana44]

Well, only on harder acceleration at medium to high speeds could be one of the motor mounts (with about a dozen different names), like the lower one on the passenger side and below the alternator.

A weak strut could allow this to happen, but not very likely at the higher speed, that usually shows up in tire wear.

Last thing would be an attaching point that has cracked and the heavier acceleration gives it the reason to wobble, witness marks at the connections and cracks should help identify why the engine/trans is shifting, or a half shaft is getting out of alignment and causing the wobble.