TT Parabolic Leafs and kit installed, now gear changes are clunky.

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Oct 28, 2019
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Hi folks, just got a brand new Terrain Tamer suspension kit installed on my 2003 Troopy, which involves a 50mm lift, parabolic leaf springs, shocks, smart coils, the whole deal, front and back.

Now when shifting, especially under load and in the first two gears, i'm getting an audible/palpable "clunk" coming from the rear end. Very noticeable, causing a lurch of sorts. A friend says it might just be my old diff suddenly showing its age with the new suspension setup.

Any advice or opinion would be greatly appreciated. thanks and cheers...
 
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Dec 17, 2019
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San Diego, CA
Do you have a photo of what your driveline-to-diff pinion angle look like?

If I had to guess, the lift threw the pinion angle off, causing excessive axle wrap (especially for a 3-4 leaf parabolic that is thinner overall to a standard leaf pack) and the extended "parabolic" overload leafs are "clapping" the main leaf. Try maybe troubleshooting by throwing some weight (like 300kg+) in the back to get the leafs to break in, and see what the drive line angle looks like under the load and see if the clunking still happens.

Usually, with diffs going bad, I historically have always heard whining before the diff starts clunking.
 
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Sep 11, 2020
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Leverkusen , Germany
The clunk may come from your back driveshaft universal joints.
I suppose, the driveshaft angel became worse with the lift and the u joints are showing their age now when working in a strange new angle. Also its likely the diff pinion flange an the driveshaft are not in a straight line any more and the axle would need to rotated a bit to make the pinion point upwards a bit to line up with the new driveshaft angle now. There are usually some wedges available to go between spring and axle to achieve this.
Better get this sorted. Imho, it's not a question of showing age but rather excessive wear.
 
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great ideas, you guys, thank you very much. i'll throw some weight into the back, see what effect that has, then get into the driveshafts and angles if need be. supposedly a lift under 2 inches such as mine shouldn't affect things, from what i've read, but wear and tear could definitely be an issue. whatever it is, i'll keep this thread updated in case it helps someone in the future with a similar issue.
 
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Update! Thank God for simple fixes. Turns out the U-Bolts for the parabolic leafs hadn't been tightened down snug, so there was about 1 mm of play in there. To his credit, the mechanic couldn't find a recommended torque for those nuts and played it safe, didn't want go too tight and mess up a brand new setup. This was his first time installing this TT suspension.

So... no more clunking during gear changes and the ride is good. A bit more firm than i wanted, to be honest, especially on the front end, but maybe that will break in a bit over time.

Thanks to all for your excellent opinions and info. Cheers.
 

EWheeler

4 Cruisers, No Garage !
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Update! Thank God for simple fixes. Turns out the U-Bolts for the parabolic leafs hadn't been tightened down snug, so there was about 1 mm of play in there. To his credit, the mechanic couldn't find a recommended torque for those nuts and played it safe, didn't want go too tight and mess up a brand new setup. This was his first time installing this TT suspension.

So... no more clunking during gear changes and the ride is good. A bit more firm than i wanted, to be honest, especially on the front end, but maybe that will break in a bit over time.

Thanks to all for your excellent opinions and info. Cheers.
Time to find a new mechanic, that is unacceptable and a lousy excuse! Any mechanic worth their salt can figure out torque required for damn near any fastener given it's diameter and head markings, or diameter and function of said fastener. Glad it was an easy fix and nothing was damaged.
 
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Time to find a new mechanic, that is unacceptable and a lousy excuse! Any mechanic worth their salt can figure out torque required for damn near any fastener given it's diameter and head markings, or diameter and function of said fastener. Glad it was an easy fix and nothing was damaged.
ha ha, i hear you, trust me. unfortunately i'm in a third world country, as far as technical training goes. as an example, in 11 years i've never seen tires inflated properly. what you wind up doing is hopefully finding an honest mechanic who at least will admit their shortcomings instead of botching the job then admitting nothing. so i got my guy, and he's honest, and we do the best we can. as you say, glad nothing was damaged. whew!

oh, just because it was such a simple fix doesn't mean i don't really appreciate all the advice here on the forum. just by reading through and attempting to understand the potential issues, i learned a lot and that's always fun. thanks!
 

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