Driveshaft issues with longer transmissions

[brushwolf]

Old article and it is a 58 shaft which I understand to be a little shorter, but the mechanics and theories should be the same..

http://www.superchevy.com/how-to/engines-drivetrain/sucp-0209-1958-chevy-driveshaft/

In this article they talk about front yolk angle being ideally 90 degrees to the front U joint, but the front U joint is on the front yolk, so how could it not be 90 degrees?

And in threads on driveshaft discussions they speak about "out of phase" being correct, contrary to most driveshafts having to be "in phase". I assume they might be talking about the same thing, but maybe not.

It sounds to me from the article like they are saying that ideally the front section of the driveshaft would extend straight back from the tail shaft, with no down or up angle in front part of driveshaft relative to crankshaft and tail shaft angle at all (essentially a straight line..) - until you get past the hanger bearing. Am I interpreting that correctly, or not?

And if one were to assume the angle of the engine, transmission and front portion of driveshaft were in a straight line and at 3 degrees from horizontal (down), then wouldn't the yoke on the rear axle need to be positioned 3 degrees up (or a little less allowing for torque movement of axle)? Not clear to me...

From the article:
"In some of these stock-configuration '58-64 big cars the yoke (... Do they actually mean the hanger bearing here..?) holding the front portion of the two-piece driveshaft was intended to be at 90 degrees to the front U-joint (at the transmission end). This controlled secondary couple loads. The rear half of the driveshaft then went on the required angle to properly connect with the differential"...

Looking at the pic (Inland, I believe..), where is this "out of phase" referred to in some of the driveshaft commentary seen? Looks to me like the yolks are in phase, rather than out of phase on the front shaft... Or my understanding of that is backwards..

Or, does that "out of phase" commentary mean the yoke on the rear driveshaft needs to be installed on the splines so that the rearmost yoke provision for the rearmost U joint is 90 degrees off from the yolk provisions for U joints on the rear of the front driveshaft?

And how do they get that hanger bearing on the shaft, install it before one of the yolks is welded to the front shaft? Or does the hanger bearing come apart somehow, so if the bearing goes out it isn't near impossible to replace without a new front shaft too?

Thanks, Mike

 

[brushwolf]

I see the original units were quite a bit different, which just leaves me more confused. But the hanger bearing looks easier to replace... Perhaps the rear yolk of the Inland front shaft bolts on splines similarly and allows replacement of that bearing.

https://www.lategreatchevy.com/assets/pdf/lategreat/1958-64 DRIVESHAFT ASSEMBLY.pdf

Another aftermarket (Performance Driveline) fully assembled two piece with telescoping rear section for purposes of phasing clarification..
Thanks, Mike

 

[heddrik]

Kind of a mess to interpret all this , I'm sure others on this site have done this and you could do a search on the site. I interpret the out of phase as the U joints being 90 degrees to each other but that's just me. Good luck, looks like a pain in the butt to me but hope you get what you want.

 

[brushwolf]

Yep, actually had searched it on here and Chevytalk and read many hours of postings. But, most of what I found relates to more common transmission swaps like a Muncie, T10, 700R4, etc., which are all shorter transmissions than the T56. Tremec may be close.. Have searched posts of other users mentioned to have done a T56 too, but must have missed them if they are there. Search term "T56" just returns an error message, because the system doesn't allow 3 character search terms.

Few posts I have found on T56, the owner had a shop do the driveshaft and still has issues. I want to have a pretty clear idea of what needs to be done myself and how the factory intended it to work in the first place. Have read some really long threads and some real ordeals gone through by others trying to get rid of driveline vibration. Saga's actually, months and months long with multiple parts replacements and every conceivable approach taken before finally resolved, if resolved.

I don't mind bringing a driveshaft or some other part to a shop to hire some expertise, but not that keen on bringing in the whole car and saying "fix this issue somehow". Not decided on whether the extra long T56 transmission might make it more feasible for me than most to possibly use a one piece driveshaft either. So kinda want to figure out what I need to do in both cases (1 and 2 piece driveshafts). Have a "Plan B" at the ready, so to speak.

Hope to get ahead of some potential issues by clarifying it in my mind before doing stuff on the car that is much harder to fix later than earlier, or buying expensive parts that have to be replaced or modified all over again. Like doing the floor and braces and finding I am gonna have to decrease engine angle with a new floor fairly tight against the transmission.

 

[heddrik]

Sounds like a wise approach to me. I like the idea of a 3 on the tree because the cars came that way, no mods necessary! And I don't need a 4 speed for my kind of driving. Lazy I guess. I have seen a lot of issues with newer trans on this site, kinda scares me away . Good luck .

 

[brushwolf]

Yes, I was just going to leave my 3 speed on the column too. Easy.. And then after I thought about my preference for open highway driving I got an OD GM manual, then concerned about torque capacity of the GM unit and simultaneously stumbling across the Offenhauser bell adapter figured I should probably use the stronger Ford T85 OD instead.

Then again, I know how nice a T56 shifts and cruises the open highway with torquey low gears as well since I had a TA with T56 for at least a decade and it was a blast to drive in any circumstance with that gearing. To use that take-out transmission though, I had to rebuild it first. 5-6 were out.. Very complicated transmission compared to toploaders I had rebuilt before.

And then wanting to retain the bench seat, figured I needed to relocate the shifter to accommodate that. Big project in itself just moving the shifter. Took weeks cuz no machine shop had a hard enough bit to drill thru the shifting shaft for a roll pin hole necessary further forward. Finally got it done with a special bit ordered from Chicago by the machine shop.

The floor mod's shouldn't be much added work being I was doing the floor anyway. But I wasn't aware of the angle issues with the 2 piece driveshaft, so now there is that or different array of complications to use a 1 piece shaft (clearance and reinforce frame tunnel, relocate emergency brake mechanism).

So, I definitely hear you. Every change introduces more and more other issues to contend with.

Mike

 

[Jeffrey Osstyn]

I see the original units were quite a bit different, which just leaves me more confused. But the hanger bearing looks easier to replace... Perhaps the rear yolk of the Inland front shaft bolts on splines similarly and allows replacement of that bearing.

https://www.lategreatchevy.com/assets/pdf/lategreat/1958-64 DRIVESHAFT ASSEMBLY.pdf

Another aftermarket (Performance Driveline) fully assembled two piece with telescoping rear section for purposes of phasing clarification..
Thanks, MikeView attachment 66626

This is the setup I run with my Tremec. I had it done by Empire in Calif. Mail ordered it no issues, fast service.

 

[La Hot Rods]

When they speak of out of faze, the factory front shaft has the u joint yokes at 90 degrees form each other.

 

[ragtp66]

This is an original front driveshaft with the yoke 90* OUT of phase. In phase just means the u joints are in the same plane

 

[brushwolf]

What is the reason the stock driveshaft is apparently supposed to be factory out of phase on the front shaft, but on all pics of aftermarket shafts I have seen it appears the yokes are in phase on the front shaft? And all the stock, aftermarket, or updated rear shafts have the yokes in phase also.

Are there two different theories on which is right? I know I have read that a common mistake is to change the front shaft to in phase and the factory apparently wanted it out of phase and warned that vibration may result if installed in phase. Or so I have read anyway..

 

[brushwolf]

I took these pics off another thread where there was a question about whether the motor was sitting on the mounts too high. And have read other threads where there were concerns about motor mounts on a 348 sitting too low and causing interference with some steering gears and the power steering pump.

Given that I don't much give a hoot about whether I have an original style pump (and have manual steering now, but want PS), can one perhaps just use the shorter motor mounts (ala similar era TBird) and just use a smaller aftermarket pump or separate PS pump reservoir to get around that issue and perhaps change the motor and transmission plane to around 1-2 degrees down instead of 3 degrees?

I am thinking that the shorter motor mounts, possibly combined with shorter motor mount frame pedestals would yield a little more floor tunnel clearance for a T56 and at the same time keep the longer tail of the T56 from pointing as far down in the frame tunnel as it would otherwise. I know with headers that might create other issues too, but I have 2.5" cast factory manifolds so don't have to worry about that.

Thanks, Mike

 

[brushwolf]

Looks like I have the shorter 1 3/4" tall mount interlocked style mount already on the engine... Not sure if I got them from Show Cars, or where. Looks like there are inserts welded on the inside of each center bolt mount ear to strengthen and narrow them, but still the inside width is 2 7/8" and not 2 5/8" where the center bolt passes through though..

Since the engine currently in the car is a six cylinder from the factory (....who would order a red 60 Impala hardtop with a 6 cylinder when gas was 45 cents a gallon.....?), I surmise the 6 cylinder frame part of mounts will have to be removed and others installed.

The 60 BelAir parts car had a V8 small block previously and frame mounts are still there, but it could have been swapped in too.

What size is the frame pedestal supposed to be in a 1960 348 car? Same as a 283? Is there a separate set of existing bolt holes there on the engine crossmember to just bolt them in, or do you have to drill some new holes?

Here are pics of new and used 58-64 V8 mount images and the red background pic is for a 6 cylinder according to the llisting. 6 frame mount does look taller and new 8 frame mounts look slightly different than originals.. mounts look sturdier than originals on the edges

 

[brushwolf]

Then there are these listed as for a 60-61 Impala with 348 that look nothing like the others. Is the seller wrong about what application they actually were produced for?

 

[Jeffrey Osstyn]

Here is how I did my accessory drive, using parts laying on the shelf avoiding the over priced aftermarket set-ups.
Of course nothing close to stock, but it's a driver, 10k miles this year, and it works. PS, 600 box, Global West steering.
To find out what will work, do a mock up, see what fits. That is the only way to find out for sure.

 

[Jeffrey Osstyn]

First install I used stock replacement rubber mounts, drivers side mount separated very quickly and I had not done anything abusive. Switched to the energy suspension mounts, this raised the engine up about a 1/4". Will see how long they last.

 

[ragtp66]

What is the reason the stock driveshaft is apparently supposed to be factory out of phase on the front shaft, but on all pics of aftermarket shafts I have seen it appears the yokes are in phase on the front shaft? And all the stock, aftermarket, or updated rear shafts have the yokes in phase also.

Are there two different theories on which is right? I know I have read that a common mistake is to change the front shaft to in phase and the factory apparently wanted it out of phase and warned that vibration may result if installed in phase. Or so I have read anyway..

I’m not a GM engineer so I can’t tell you WHY they did it that way but they obviously had a reason for doing so. A nasty driveline vibration between like 30-45 mph is what would happen. I had my driveshaft re-tubed and I made sure they wrote it on the repair order that when they assembled it that it was to be 90* out of phase. The guy tried to convince me that it was wrong and somebody previously must have changed it. I showed him that article and a picture from the factory parts book showing it out of phase before he stopped insisting it was wrong.

 

[ragtp66]

Then there are these listed as for a 60-61 Impala with 348 that look nothing like the others. Is the seller wrong about what application they actually were produced for?

No idea what these mounts are for but they are not for an x frame. There are no through bolt holes to attach the engine side mount to. The Only two I have ever seen is the shorter v8 mounts and the taller 6cylinder. 348/409 architecture was made to utilize same engine mounting and transmission mating to keep costs low.

 

[Silversport 63]

I can tell you what I have done. '63 Impala, Tremec 5 speed. In order to get the transmission in at a 3 deg. down angle (or less), had to cut the floor and raise it up about an inch. This leaves a very minimum space between the top of trans and floor, maybe 1/4" in the closest spot. This also leaves a minimum clearance for the headers to clear the lower control arm. I can not lift the trans up any more without the headers hitting the control arm. With a 2" drop on the front spindles, header to ground clearance becomes a problem, also the mufflers are tucked up as close to the floor as possible without hitting, many hours of exhaust pipe mods needed to get there! I have dragged mufflers for many miles while fine tuning this.
So, transmission up as far as it will go, I run a two piece drive shaft. Center bearing switched to solid mount so a slip yoke needed on rear shaft. The shaft out of the trans actually goes up 1 deg. to the center support bearing. I can adjust the rear shaft angle pretty much anywhere I want without a problem hitting anything. Currently running 3 deg. down. No vibrations with this setup.
As far as the frame center section goes, the u-joint on the transmission end is huge compared to the old one (saginaw). So the bracing needs to be cut away to get the joint to pass through. Tough to do neatly with the car assembled.
Have fun!

 

[gesto]

Brushwolf,

I just read through this thread and am planning on a similar engine/trans set up. I hope you will update this when you get everything together. Since you have a 1960 I am reading through all your threads, including floors. You might check the Conversions and Hybrids forum on www.ls1tech.com. There are several X-frame LS swaps in that thread. There has to be one that swapped in a T56. Thanks!

 

[Silversport 63]

Is the after market support bering from inland easy to pass thru the tunnel