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Replacement Fuel Tank and Drive Shaft Angle

Posted: Wed Jul 15, 2020 5:49 am
by powderhound
Hello GenVibe,

(Too Long, Don't want to read? Skip to the second half/bold lettering. Thanks)

YouTube Video showing my problem. Described below.

Thankfully (sarcasm), COVID19 continues to rage and work-from home continues to be the norm for my wife. (Not to worry, we will soon be stuffing children into schools that, effectively, are on fire! But, hey, it's cheaper then keeping them out of the building. Again, sarcasm-ish) Point is, I've been able to keep the vibe on blocks for a ridiculously long time because, A) I have only a slight idea of what I'm doing. B) We have another vehicle to use as a daily driver C) Work from home is here to stay for us (yup, a fine example of inequality) D) Sourcing parts for a AWD Vibe is time consuming! E) My wife is stubborn. We will save this car!!!!

So, it started with pulling the 2004 Pontiac out of Northern New Hampshire where it lived in a snow bank....and that was the least of the harshness. We changed the fluids and the car sat in dry storage in our barn for a couple of years. Eventually we decided to part with with 83 300SD my wife drove 180 miles daily and transitioned to the vibe. She drove it for a few months. During the early days of shutdown, I noticed the right rear passenger side wheel was toe'd in. Hmmm??? Drove it...felt fine. Also, no excessive wear on the tire (yet). Upon closer inspection and some consultation....it was determined the rear subframe was rotting away! UNDERSTATEMENT!!!! So much for state safety inspections...haha!!! WOW! https://youtu.be/4BUfI5rkw3E

So, replacement subframe acquired, replacement subframe sandblasted, repaired (minor hole in tube. welder repair for $70. worth it...I THINK), Old frame removed, differential removed for servicing (separate and still unfolding saga), Old fuel tank removed, bolts broken, replaced, holes re-tapped, threads repaired, everything blasted and painted/por15 or powder-coated. RIDICULOUS attention to detail for a $1500 car....I'm stoopid!!!

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YouTube Video showing my problem. Described below.

Okay...so here is the rub...literally. THE FUEL TANK DOESN'T SEEM TO FIT. The drive-shaft aft of of the carrier bearing is making contact with the fuel tank saddle when moved into the near horizontal position. The tank (IGM65A) appears identical and by all practical measurements, seems to be the same. It is hanging a tad bit lower then the stock tank and we had a real fight to get the new straps secured to the frame (Used two large nuts as washers to makeup the gap). The new tank is snugged firmly up against the underside of the body and fuel pump access and wire harnesses appear to be in the correct position. It seems like the old straps wouldn't fit either, what's left of the literal "rust belts". For all practical purposes, it seems like the fuel tank is a little bit larger then the stock tank. So, I have some concerns.....

Without being a master mechanic or even a make-believe engineer, I don't want to put this thing back together only to discover that the drive shaft doesn't line-up with the coupler on the rear-end.

Can anyone tell me what the angle of the drive-shaft should be on a 2004 Vibe/Matrix? It's hard to say, but it appears I will have around 5 degrees slope leading towards the rear end from the carrier bearing/mount.

Can anyone provide me a straight line vertical distance from a known point on the body (cross-member perhaps) to the center of the drive shaft universal joint mating position with the differential?


I'm hoping the replacement fuel-tank is okay. If not, this story is about to get even more frustrating!

Last week I looked at a 2009 Matrix and it appears the shaft is pretty much horizontal (180 degrees), but I don't know for sure. I had my head pinned under the vehicle at a used-car lot.

Please help! Thanks so much!!!!

Re: Replacement Fuel Tank and Drive Shaft Angle

Posted: Thu Jul 16, 2020 7:20 am
by zbyers
I couldn't tell you the driveshaft angle off the top of my head. We sold the one we replaced the subframe in (as can be seen here: viewtopic.php?t=47305)

That said, if you had to use some washers to shim the strap, perhaps that has allowed the tank to be dropped a little lower. Where did you source the replacement tank and straps?

We replaced the tank and straps on a different AWD model, which we discovered when doing that subrame... We had absolutely no issues with clearance on it.

Any pictures of the issue you're running into? Depending on picture size, you may have to host them elsewhere, and link to them here.

Re: Replacement Fuel Tank and Drive Shaft Angle

Posted: Fri Jul 17, 2020 6:22 am
by powderhound
Hello again and thanks for the reply,

Fuel tank is super tight against the underbody of the car...so, if we have a fit issue it is the geometry of the replacement. But, the exact dimensions and the differences in the new tank are illusive AF!

We sourced the tank from https://www.gastankdepot.com. It was drop-shipped from a supplier in upstate New York.

Where’d you source your replacement tank?

Re: Replacement Fuel Tank and Drive Shaft Angle

Posted: Fri Jul 17, 2020 7:37 pm
by powderhound

Re: Replacement Fuel Tank and Drive Shaft Angle

Posted: Fri Jun 17, 2022 6:44 am
by SSizler
Sounds like they sent you a base gas tank instead of the proper, smaller AWD gas tank.
Did you ever get this resolved?
I am sourcing a rust free replacement rear subframe for future installation in my 06 AWD, and was curious why you had this problem.