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Good Vibrations

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PNZWGN
Posts: 921

Re: Good Vibrations

Post#51 » Mon Aug 12, 2019 10:03 am

blueg wrote:Parker I have a couple of questions about your previous setup.
Was the getrag transmission coupled to a 617NA or gasser when you first got your truck?
Did you ever have the getrag coupled to the new 617A before getting the .113 T1 trans?
I ask because I have removed my wife's iron box 4 speed and have a getrag to replace it.
The engine is 617.952 and, if possible, I would be happy to know if I should be looking for another cross member for the install to prevent any vibration issues.
Maybe if you find another cross member to better situate your .113 I might buy your old cross member and bushed support.
I just hope the problem doesn't lie in the engine carriers as I am using the very same ones. If R&D is out and puts the trans output shaft and flange in the wrong place we will chase our tails like half baked dogs.
I have since discovered that the carriers for the G specific 617NA can be slightly and safely modified to carry the 617A motors in the wagens. I like the sturdy aspect of the redesigned carriers but price and annoyance factors harshly if they are in fact inaccurate.


Todd-

The Getrag was coupled to the 617na and the Ironbox to the 617a only. Never crossed, no gas engine ever.

I'm using the Syncro 617a engine mounts (I believe that is what we call them.) They appeared very well made to me.

Sorry... this reply fell of my radar until I dug this thread up.
"wherever I may roam..."

PNZWGN Mk II build thread: https://clubgwagen.com/forum/viewtopic.php?f=18&t=5605

blueg
Posts: 1870

Re: Good Vibrations

Post#52 » Mon Aug 12, 2019 3:34 pm

Parker.
Thank you for your reply.
I agree the syncro mounts are very well made and sturdy enough to hold 4 times the weight.
My concern lies in the accuracy of the engine to transmission positioning with the mounts.
Did you solve your vibration problem?
Did you end up using a modified T1 van transmission cross member in your G?

jtrein
Posts: 360

Re: Good Vibrations

Post#53 » Mon Aug 12, 2019 4:10 pm

Parker,
Have you tried pulling the front & rear shafts out independantly and driving it around in 4wd? Just make sure when you pull them to put the G in 4hi since the front shaft lubricates the TC. I have been chasing vibrations on G-Unit and after pulling the front shaft they went away. Just got the new shaft today so hopefully the vibrations don't come back when I put it on. Didn't re-read your whole thread and can't remember if you tried that or not, but if you haven't it is worth a shot. If either front or rear shaft is worn, either u-joints or the splined slip section they could be throwing bad juju back to the TC.
1981 280GE Ambulance - full restoration in progress
1985 280GE

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PNZWGN
Posts: 921

Re: Good Vibrations

Post#54 » Mon Aug 12, 2019 4:32 pm

blueg wrote:Parker.
Thank you for your reply.
I agree the syncro mounts are very well made and sturdy enough to hold 4 times the weight.
My concern lies in the accuracy of the engine to transmission positioning with the mounts.
Did you solve your vibration problem?
Did you end up using a modified T1 van transmission cross member in your G?


Hey Todd... you probably didn’t see my previous post from earlier today. But unfortunately, no.
"wherever I may roam..."

PNZWGN Mk II build thread: https://clubgwagen.com/forum/viewtopic.php?f=18&t=5605

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PNZWGN
Posts: 921

Re: Good Vibrations

Post#55 » Mon Aug 12, 2019 4:37 pm

jtrein wrote:Parker,
Have you tried pulling the front & rear shafts out independantly and driving it around in 4wd? Just make sure when you pull them to put the G in 4hi since the front shaft lubricates the TC. I have been chasing vibrations on G-Unit and after pulling the front shaft they went away. Just got the new shaft today so hopefully the vibrations don't come back when I put it on. Didn't re-read your whole thread and can't remember if you tried that or not, but if you haven't it is worth a shot. If either front or rear shaft is worn, either u-joints or the splined slip section they could be throwing bad juju back to the TC.


I’ve got nothing to loose at this point. I will have to give it a try. Might be something I can get into on Friday.

Thanks for the suggestion and please keep us posted on how the new front drive shaft works for G-unit.
"wherever I may roam..."

PNZWGN Mk II build thread: https://clubgwagen.com/forum/viewtopic.php?f=18&t=5605

blueg
Posts: 1870

Re: Good Vibrations

Post#56 » Tue Aug 13, 2019 9:30 am

Parker.
Have you considered finding someone that would let you strap your G into a dyno and have someone drive it fully engaged at the speed you have the worst vibration while you circle the truck with eyes on and a stethoscope to pinpoint any vibration harmonics?
Failing that you could build a crib with rollers and strap it in for the same check.
I built a crib some years ago for a stubborn vibe in one of my vans. Did not cost near as much as the chase and replace thing I was doing up to that point and I found the culprit in first 10 mins on the crib.
Broke the crib down and used the lumber kept the rollers.

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G Nome
Posts: 4077

Re: Good Vibrations

Post#57 » Tue Aug 13, 2019 11:03 am

Blue...any pictures of said "crib"?

Great suggestion. Not for the faint of heart I am sure.

Kent

User avatar
PNZWGN
Posts: 921

Re: Good Vibrations

Post#58 » Tue Aug 13, 2019 11:46 am

Update... sort of. After all of these attempts at adjusting the "elevation" of the rear transmission output flange (no improvement) I decided to take a closer look at the lateral or side-to-side position of the flange as I mentioned in yesterday's post. The entire engine and transmission assembly sits a few degrees cockeyed and I've always understood this to be the case with 460's at least.

After much studying and thought I decided to "pivot" the engine/transmission assembly slightly around its yaw axis towards the passenger's side in hopes of better aligning the two flanges. I had nothing to loose at this point. I loosened all of the motor mounts so to not stress anything and was able to move the rear Ironbox transmission mount a little more than .5". I made a crude custom rear transmission cross member to secure it because now the rear of the transmission was out or alignment with the bolt pattern on my factory rear transmission cross member. I hunkered everything down and tightened-up the motor mounts up front and went for a quick road test..... no improvement.

I may still experiment with the same vertical adjustments I made previously now that the transmission output flange's lateral angle of attack is different, but I'm somewhat limited by this crude cross member I created.

I don't know what else to try other than removing each of the drive shafts and road testing. Sigh...
"wherever I may roam..."

PNZWGN Mk II build thread: https://clubgwagen.com/forum/viewtopic.php?f=18&t=5605

User avatar
PNZWGN
Posts: 921

Re: Good Vibrations

Post#59 » Tue Aug 13, 2019 12:12 pm

blueg wrote:Parker.
Have you considered finding someone that would let you strap your G into a dyno and have someone drive it fully engaged at the speed you have the worst vibration while you circle the truck with eyes on and a stethoscope to pinpoint any vibration harmonics?
Failing that you could build a crib with rollers and strap it in for the same check.
I built a crib some years ago for a stubborn vibe in one of my vans. Did not cost near as much as the chase and replace thing I was doing up to that point and I found the culprit in first 10 mins on the crib.
Broke the crib down and used the lumber kept the rollers.


Todd... I have not, but I did capture some footage of the old center drive shaft with my GoPro before I replaced it with a new one. I'm trying to upload a ling to post here but Google photos is fighting me.
"wherever I may roam..."

PNZWGN Mk II build thread: https://clubgwagen.com/forum/viewtopic.php?f=18&t=5605

blueg
Posts: 1870

Re: Good Vibrations

Post#60 » Tue Aug 13, 2019 1:54 pm

Parker. I would divide and conquer in your shoes.
Disconnect all three shafts.
Run the engine with the trans in neutral--no vibration?
Run the engine with trans in every gear at varied RPM under no load--no vibration?
connect the drive and propeller shafts one at a time putting load to assembled drive train.
Sooner or later the chatters have to be obvious.
G Nome.
Sorry I have no picture of the crib. You can see by my lack of pictures on this site. Not a big priority for me.
The crib I assembled out of 2 16' 2X12 spruce and some 1X4 ribs to separate them the width of my vans wheeled axles.
I purchased 12 HD flat rollers with self mount brackets from Princess Auto (Canada)
and mounted 8 of them to the 2X12's laid flat and distanced so I could drive onto all eight rollers with 2 rollers per tire.
The other four rollers I mounted at an upward angle in front of each of the roller sets under the wheels to act as a forward chock and to give little resistance on the motion.
I mounted four dock rings forward and rearward of rollers and secured the truck in place.
Spacing of all rollers will be determined mostly by tire diameter.
This setup allowed me to idle the truck in gear and not have to remain in it.
A stick on the accelerator gave me speed.
I would recommend a second person help with the testing but I prefer to do technical things solo.
Whole crib cost just over $100 and took about 1 hour to assemble.
Saved me a lot of hassle and money.

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