Itinerant Air-Cooled

83 air cooled. Manual trans. In neutral idling and sometimes shifting the van vibrates hard and kind of loud. Feels like I am sitting right on it. Not sure what it is or where to investigate. Has fresh oil and is timed correctly. Been running warm with oil temps 225 to 255 avg. Suggestions?

First started today after a few hours of driving on highway. We've done a lot of climbing recently. Will look under and listen close to see if I can get a better idea of things. Currently in Butte, MT headed to Bozeman.

83AC wrote: ↑

Thu Jun 01, 2017 4:02 pm

83 air cooled. Manual trans. In neutral idling and sometimes shifting the van vibrates hard and kind of loud. Feels like I am sitting right on it. Not sure what it is or where to investigate. Has fresh oil and is timed correctly. Been running warm with oil temps 225 to 255 avg. Suggestions?

First started today after a few hours of driving on highway. We've done a lot of climbing recently. Will look under and listen close to see if I can get a better idea of things. Currently in Butte, MT headed to Bozeman.

We need as specific of a description as possible.

If it vibrates in neutral, does it go away when you step on the clutch? Does it get worse when you step on the clutch?
If it vibrates when shifting, your foot is on the clutch when you shift, so think about that possibility that this is clutch-related.
Any snapping sounds precede this?
Did it develop all at once or over time?
Colin

Alright I have more specific info now. Yes I think clutch related and transmission - here is info - help me problem solve. When first noticed it was in town after hours of highway driving. Did not notice a snap ... I don't recall any. Engine oil temp at time of noise and vibration was hot 250 plus. After cooling down an hour or so, started and no vibration, in fact after some in town and then about 60 highway miles it never returned. What did return: whenever starting in 1st from stop it has a hard time seeming to get going then seems to catch and whoosh we are off. Then shifting into 2nd and 3rd, clutch goes in and I hear a rrrrrrr sound loudly which goes away once I let foot off clutch and engage gear. This all happened when engine oil temps are similar to what I mentioned before. Happens in 4th as well but not as loud. This all started up today, with the only preceding symptom specific to this being hot oil temps and some of the difficulty with getting going in first, which has been ongoing maybe since a day or two ago - just a day I think.

Awaiting input as I'll want to try to make some moves on this tomorrow while I have some in town down time.

Amskeptic wrote: ↑

Fri Jun 02, 2017 7:07 am

I am guessing that you have a cracked clutch operating shaft and the release bearing is protesting its loss of concentricity.

Why would the issues I am having only occur at high temps or after long drives? This morning cold and driving about 30 miles, with cooler ambient and oil temps, no issue other than slight noise? I will be checking your recommendation either way, but trying to understand.

Thanks!

is it possible the shake is a cylinder dropping out?

sgkent wrote: ↑

Fri Jun 02, 2017 11:15 am

is it possible the shake is a cylinder dropping out?

Given that it happens after extended drives at higher oil temps that is my primary fear. It has 3.75 quarts of fresh oil in it, no leaks, 20w50, and I checked oil after first hundred miles and the level was great. I think engine seems to run somewhat rougher.

Colin, just finished check on the clutch lever, engine off and on. No vibrations or weird feelings there . . .

83AC wrote: ↑

Fri Jun 02, 2017 9:18 am

Amskeptic wrote: ↑

Fri Jun 02, 2017 7:07 am

I am guessing that you have a cracked clutch operating shaft and the release bearing is protesting its loss of concentricity.

Why would the issues I am having only occur at high temps or after long drives? This morning cold and driving about 30 miles, with cooler ambient and oil temps, no issue other than slight noise? I will be checking your recommendation either way, but trying to understand.

Thanks!

I have no fricken idea.
Colin

i had some weird noises in my 83AC when shifting, but no symptoms of growling with clutch depressed nor hesitation. it would produce slight clang when starting in 1st and reverse. it was my tranny mount, which i replaced with the power flex bushings. thats gone. next i replaced all the bushings in/on/around the shifting rod/guide pin (when i replaced the fuel tank as dropping it is required to do this) as the transmission vibrations were transmitting from the rod to the body and no more noises. I also replaced the clutch slave cylinder when i first bought the van and flushed the whole brake/clutch system. does it growl when in neutral with the foot off the clutch? maybe your tranny mount is completely shot throwing the whole gear/shifter alignment out of whack.

parts for the shifter/mount bushings:

http://www.t3technique.com/suspension-b ... shing.html (59mm)
https://www.vanagain.com/shop/shift-gui ... 2-vanagon/
https://www.vanagain.com/shop/shift-bus ... nd-diesel/
https://www.vanagain.com/shop/bushing-f ... n-shifter/
https://www.vanagain.com/shop/bushing-f ... shifter-2/
https://www.vanagain.com/shop/center-shift-bushing/

the temp issue could be a tight lifter or low valve clearance on one valve. Have you checked the valve gap recently? It could also be electronic related - a coil or module that is sensitive at higher temps.

Well we stopped in to Larry's Auto in Livingston, MT and did some test driving and trouble-shooting. Larry is a great guy and was very accommodating - if you are ever near Bozeman and need help, he is your man. Anyway, issue went away and never has returned. In troubleshooting the only real thing we could trace to was where we filled up on gas, also our first fill since returning from CA. We decided these things may have been related and switched after that to premium fuel. No more issues and fuel economy remains 18-20mpg. I've now had another funny issue come up - see new troubleshooting diagnosis thread "clunking then gone . . ."

how old is your fuel tank? maybe your pump sucked up some rust crud at the pick up restricting the flow. no fuel pump noise? it may be that you sloshed around the crud away from the gas pick up tube/filter inside the tank with a fresh fill.