Driveline shudder/vibration

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Joined: 23 Oct 2023, 14:26

Driveline shudder/vibration

Post by 63 AZAM »

Hello everyone,
After many years of admiring the engineering and design of the 2CV I finally found one and purchased it.
Amazing little creatures! So simple yet so well thought out!
I’ve got an issue that I’m trying to figure out but don’t know if it’s inherent with the design of the front drive featuring single Cardan universal joints or if something is amiss…that I can’t find!
The way the front suspension moves on this vehicle seems to be asking for Cardan style joints to do the impossible in my opinion.
What I’m experiencing is a nasty shudder, like the entire driveline is jumping especially under load at around 20kph, terribly noticeable on a nasty hill when you have to give up and downshift into 2nd gear.
I’ve checked the obvious, u joints are all tight and smooth operating, no play in the axle splines, u joints are “in phase” aligned. I do notice that the right side u joints DO NOT align 100%, approximately 10 degree, but not a full spline tooth misalignment.
Over 20kph it smooths out and running at high speeds it’s smooth as silk.
The car has a relatively new galvanized chassis, it runs well for 18hp 🤣,shifts beautifully….I’m out of ideas!
Any ideas are more than welcome.
I simply have no one to consult, or access to another early 2CV as a reference. I just feel that this shake cannot be good for anything mechanically.
Thanks much, Greg
Posts: 169
Joined: 22 Feb 2005, 03:07
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Re: Driveline shudder/vibration

Post by thorter »

I never had an early 2CV, but I seem to remember the non constant velocity drive shafts were a feature, and the instructions were to slip the clutch when manouvering at low speed. When these cars were made, the French economy had not yet recovered after the war, and low cost simplicity was essential.

Later cars had a 600cc engine and full CV drive shafts, but very unlikely that parts are interchangeable.