73 W100 Drivetrain vibration

I’ve been making slow progress on my 73 W100 and got to the point of driving it down the road. I got up to around 20 mph and I get a severe drivetrain vibration. It literally shakes the transfer case lever like crazy. Reading some I see that it might be the driveshafts may not be in parallel.

Looking under the truck the main rear driveshaft is definitely not parallel when looking at the alignment of the yokes. I’m thinking this could be a cause of my issue? Not sure how it could be off-center unless someone pulled the drive shaft and didn’t index the spline when they put it back together?

At any rate if this is something that needs to be corrected I’m guessing I should just replace the u-joints? Any seals I should sway while I’m doing this?

I did check the mounting points and mounting bushings for the transfer case and all looks good there. The front drive shaft yokes all look to be parallel.

One of the pics is upside down but it still shows the difference in yoke orientation.

Thanks in advance.

Here is my advice and I have fixed many of these. First double check all the joints. Recommend dropping the shafts and checking all the caps. If a joint is seized it can cause a problem. Once the joints are checked and ok you need to be sure the shafts are phased. If that is ok you will have to most likely twist the transfer case crossmember to correct the short jack shaft angle between the transmission and transfer case. If you can get good pictures I can try to direct you on what to do. Like I said I have done many.

Cool thanks...yes, phased is probably the better word than parallel. Take pics of each of the u-joints and try to do so at the same orientation?

By the pictures it looks like it might be one spline off, but that could just be the angle of the picture. I would drop the shaft out and check each U joint to be sure everything moved smoothly, then be sure the shaft has the joints in phase. It doesn't take much roughness to give a vibration.
I might also be concerned with how much engagement there is on the splines, it looks like there isn't much shaft inside that yoke. Gene

If possible try to get a complete picture including the yokes of each shaft. The intermediate or jack shaft is the one I would like to see

Got it. Will grab pics tonight. Thanks!

If the splined yoke has never been slipped off of drive shaft, it all should be fine. I learned that long ago because some shafts do not have that double key that only lets the two go back together one way. If you index it any way you want, there will be huge bad vibes.

I have no idea regarding the history of this truck. The seller fibbed and omitted a lot of things so I don't know what's original or been monkeyed with.

Id start with correcting the phase angle (new U joints as long as your there)

NITROUSN.....here are some pics. Let me know if I need to get any other.

More

Some more

That’s it

Yikes. I see three problems. Front shaft out of phase, rear shaft out of phase, wrong transmission. The first thing I would do is remove the front shaft and leave it off for now. Remove the rear shaft check the joints, replace if needed and re-phase it. Re-install it and drive it. I doubt it will change but its worth trying. The transmission is a 2wd long shaft with a slip yoke. It should have a short tail shaft with a bolt on yoke. The shaft should be with 2 joints and a slip yoke. So doing as I suggested check if it vibrates, If ok by some chance you can check the front shaft joints and re-phase it install and see how that works. Now if it vibrates with just the rear shaft I would try this. Unbolt the transmission shaft from the TC and see if it will slide into the transmission at least 1/2 to 1 inch. If it does not slide the transmission may be loaded against the TC which will vibrate. The motor and transmission would have to be moved forward. Band aide fix and not my choice. What is there is not right and kind of a hack job. If it were mine I would be doing the transmission back to the short style and get the right drive shaft, Right now I will just about bet the problem is between the TC and transmission.

One other item I would like to see is the transmission cross member and mount areas. Also you could remove both F&R shafts put the TC in neutral and run it in gear and see what it does. Look at that short shaft and see how true it is. The TC and transmission center lines would have to be so true for this to even try to not vibrate. I just see a problem there that most likely will not go away. Just to wrong.

driveshaft out of phase will definately cause the vibration you describe, bought a ramcharger with same problem, i pulled the splines apart and reindexed them and it drove like new.

NITROUSN -

Thanks...ugh...another clear example of why not to buy a vehicle from across the country without inspecting in person. A drunken eBay purchase....

I'm assuming this is the type of jackshaft I need if I had the correct short tail trans? I can check FSM when I get home but do you know model number of correct tail trans I need? I assume these are a little hard to find and I have to decide whether I want to sink the cash or just part ways. It's a shame, because it's a cool truck. 99% rust free, 400bb, a/c, cruise, two tanks, camper package...etc.

I will probably mess with it removing the front driveshaft and getting pics of the trans mount tonight...grrrrr.......

The biggest problem is probably this. Between the missing 2nd u-joint and being squished against the transmission it's not getting the proper movement it needs.
It might not be a bad idea to clean up the splines on the end of the driveshaft either to make sure nothing binds.

The proper short tail shaft transmission shouldn't be too hard to find. Even with big block quite a few pop up on car-part.com and are in the 300-500 range. You might have to get it shipped but a buddy of mine even had to do that to get a small block 904 recently because there was none local!!??

Same area code as 5thAve...just passed on a BB shorty 727 with a weird motorhome tail shaft. I have an extra 2 already, but as he mentioned should be able to find one close to home.

Thanks everyone!

NITROUSN,

Requested pics of trans mount.

More....

Those shorty 727s came in a lot of different trucks. My 85 D350 crew had one but it was a 360. Still easy fix, you just need the output shaft and tail shaft to swap into yours.

even 89-91 cummins trucks were running the short shaft 727 with a big yoke------all you need is the tail housing -main shaft to rebuild your tranny and there is good stuff in there like a 5 pinion sun gear,-----the big yoke will also fit on the back of your old push button transmission .....

Guys,

Is this what I need? $110 on eBay.

yes that appears to be the correct intermediate shaft you would need.

That is the right tail shaft from e-bay and the short shaft pictured is correct but you can see it also is not phased correctly. Cross member looks good. Look and see if the top of the cross member to frame rail is shimmed down. I see a gap and most likely the guy who worked on it was trying to correct the angle due to vibration. As said best to replace the tail housing and shaft along with the correct short shaft. Bolt the cross member solid and you should be good to go. Question with the truck in park and you increase the rpm's is there any vibration? Just making sure the converter in correct balance wise to the motor. That would be just one more problem the builder could of caused.

No vibrations in Park with increase in RPMs. Ok I’ll snag the rear housing. Will try to find a not so spendy intermediate shaft. Haven’t seen any others out there. I “think” it’s part number 3516037.

Also checked the driveshafts and all the u-joints were ok. Put the rear tail shaft in phase and left the front off for now. Will fix it right. Still hoping to drive it to the Nats.

Thanks for everyone’s help! I’m sure Ill be back with more questions shortly.

No vibrations is good at least there is not another problem. How much did they want for the short shaft? They were the same for many years. For sure 72-74 and I believe even older. Also same on all model 4wd 100 to 300 series. Just be sure they take the small joint.

$176.00 + shipping

Could be worse on price. Those trucks are getting harder to come by. The female side is the same on all 3 shafts. Where did you find one?

It's on eBay right now.

Sent you a PM.

I'm going to put a NV4500 in my 74 with the divorced T/C. The NV is about 8" longer than the NP435 in it. I was looking at how short of a shaft I could make and/or moving the transfer case back about 4-6 inches but that solution you have right there never crossed my mind. Looks like something the redneck Carolina boys that owned my truck before me would have done.

was you able to find the parts you need?

Yep...mine was butchered a bit. Got parts on the way, looking for someone to rebuild it near me.

I’m wondering if I’ll have to drop the TC if that rigged jack shaft and presses hard against the trans. Otherwise I don’t know if I can drop the trans.

That doesn't even come close to covering the problem!! I can't believe the previous owner butchered the intermediate shaft like that. BTW, If you have to replace any of the splined slip joints, you may want to consider retrofitting with the later accordion bellow boots. I did this on all three slip joints on my '72 W200.

The shaft is junk so just cut it in half. The transmission will come out then.

Good call.

Resurrecting this old thread. Finally made some progress...got the trans out, did have to cut the butchered intermediate shaft. It was jammed up against the trans. Have the correct tail case and intermediate shaft and found someone to rebuild the trans. Dropping it off tomorrow.

A couple questions...since I’m at it I’m going to rebuild the NP 205 transfer case. Doesn’t look too complex. Is there a best place to buy a rebuild kit or just go to rockauto.com?

Other question...the trans cross member was fastened to the frame with nuts and bolts. There were no threaded studs in the frame. Some of the bolts were fastened with a nut that sat between the top of the frame and the bottom of the cab which obviously there is not a lot of clearance. It’s going to be fun trying to line up the nuts on the bolt coming up much less get a wrench on them to tighten everything up. I’m wondering if this is factory?

As far as I can recall the factory cross member in that year was bolted directly to the frame rails. You might have to research that to be sure. I can not recall it being shimmed down. That 205 case is tough. I would fix any visable leaks and run it as is. Save your money.

It has plenty of leaks. I’ll get a seal kit for it and clean it up.

Ok, so I go to drop the transfer case so I can replace leaky seals. Rather work on it on the bench versus laying on my back on the garage floor.

Anyways the two bolts holding up the TC on the drivers side have some kind of cap or lock that covers roughly a 1/4 of the bolt head. It appears this cap has a base that sits under the bolt head. It hard to get a good look at them because there is not much clearance. Haven’t been able to figure out how to get a good grab on the bolt with a wrench. Never seen these kind of caps before.

Anyone familiar with these bolt caps and if so how do you deal with them?

Can you sneak a picture? Its been a long time but I can picture a plate under the bolts with a tab that is bent up against the bolt head so it will not loosen. If so you need to find a way to rap them down or pry them down. Most likely this was done on the line before any sheet metal was installed.

Saw your thread on RamchargerCentral, and answered there, but you should be able to get a wrench on those bolt heads; I don't remember a "cap" on those bolt heads. It has a small plate under the two bolts, but mine did not had a bent-up keeper on the two bolts, on my '73. As I'd said over there, I'd put new mount bushings in, while it's out.

On the transmission crossmember, mine is a bolted-on situation, also, so I'm guessing that's a factory thing. How is the tailshaft mount? Mine was bad, and the engine/tranny had torqued towards the driver side, to the point that the tailshaft mount was vibrating a notch on the crossmember. I got a new mount, loosened everything up, and straightened the whole thing out. I still have vibration that starts around 42 mph, so something is still not right on mine. Stub shaft was balanced with the other 2 driveshafts, along with new Spicer u-joints, but I've read that it does not take much to get the stub shaft to cause vibration in these trucks.

Was able to get my phone up there and get a pic. I see what I have now, it’s a pretty stout plate that straddles both bolts with a corner bent over each of the bolt heads.

Just got to get something in there to bend the corner down.

Fun.

My tail shaft was butchered like the rest of the install. The horizontal trans mount bolt wasn’t installed through the bushing that is surrounded by the rubber...it was installed through the rubber in a hole cut through under the bushing. Was hard to get the bolt out.

That's the way I pictured it. The tabs have to be bent back to get the bolts out. That case is heavy and can be a pain in the butt getting the bolts back in. If you are just replacing the seals I would do it in the truck.

where do you source the new bushings for the divorced transfer case crossmember mounts?

Mine was broken. The one on it also had a hole for lining up and bolting the bottom of the "V" to the crossmember. My replacement did not.

I don't remember the corners on my plate being bent up for a "keeper". Maybe I forgot, lol.

Good luck!

https://www.amazon.com/Energy-Suspension-9-4101G-UNIVERSAL-MOUNT/dp/B000CN9BZ0/ref=sr_1_2?dchild=1&keywords=Energy+Suspension%27s+9.4101G+Universal+Mount&link_code=qs&qid=1612973356&sourceid=Mozilla-search&sr=8-2&tag=mozilla-20

These are perfect replacements for the OEM rubber ones. I bought 205 bushings for a Bronco of that era, and they did not work. These do. Thanks goes to user KurtfromLaquinta on RCC; he;d used them when he rebuilt his 1974 W100, and they worked well for him.

alright thanks! Looks like I have to order 2 of those kits?

Yes, 2 of them.

Ok, hopefully last question on this thread. I have the trans rebuilt wit a correct tail case and intermediate shaft. Just waiting on u-joints from rockauto that have shipping delays.

At any rate, I noticed there are a bunch of washers stacked on each of my motor mounts. I'm assuming these were used to move the engine and trans back a bit for mounting the incorrect 2WD trans. In order to remove them I'm guessing I will need to mount the trans and support it with the harbor freight trans jack and then use the floor jack to lift each side of the engine and remove these washers?

Also, one freeze plug on each side have been replaced with the expandable rubber-type plugs and look to have been leaking pretty good. I'm not sure I can get at them to replace them with metal plugs, if I can't are these expandable rubber plugs a decent solution or do they typically leak?

Thanks!

I think they're a cheap easy solution for something you're about to sell, if you want the buyer to have to do it right later. NEVER in my car.

If it were me while the transmission is out I would replace all the freeze plugs I could get to. Take the washers out of the mounts and with the mounts off you should have easier access to the plugs on the side of the block. Just so you know your speedometer will drive off the transfer case not the transmission. Make a dust cap for the transmission speedometer housing. Find a rubber cap and silicone it to it.

The speedo cable was connected to the trans, not the TC. There is a cap on the TC now where a speedo cable would be connected. I don't know if my speedo cable has enough length to reach the TC.

Then you have the wrong cable. Not that it wont work. High range 1 to 1 it will be fine as long as you have the right gear for your axle ratio. Low range is another story. For now get the bugs out and the odds and ends you can do later.

you're this far into it...pull the engine and replace all the freeze plus, reseal regasket, freshen up the engine paint, etc.

The motor mount bracket looks to me like someone put a 318 bracket on a 360. The plug wire is hiding the rear lug, but it looks to me that the bracket is tight against the ear on the block, and the washers are taking up space because the bolt was too long. The front of the bracket used washers to take up the space between the ear on the block and the bracket. I've seen that trick several times before, not that I would have ever done it.

I'm in agreement with replacing all the freeze plugs. If two have already been replaced because they leaked, the others can't be far behind. Don't forget the two freeze plugs at the back of the block, between the block and the trans. Replace the crappy rubber junk with either steel or brass replacement plugs. New gaskets and a repaint isn't a bad idea either.

Its pretty easy to spend someone else's money! Gene

I agree on the freeze plugs.
For the engine mount when I had to replace my car 360 one a few years ago everything that came in was for 318 so we gave up and did the spacer thing. I forget if it's washers or a nut we used. With everything else that's been cobbled together on your truck it seems like someone threw it together with whatever parts they had or could easily find.

The poster has a 400 big block not a 318 or 360 small block.

Ugh...I've sold all of my hoists, engine stands, and tilters thinking I would never do this sort of thing again.

Once you start peeling at layers of the onion....

Looks like Harbor Freight has a decent folding hoist.

Yep

any rental places around you? just need one for the day.

Ok was able to replace two of the freeze plugs on each side with engine in truck. Trying to avoid yanking it.

However, I do think there are some more squirrelly things with my motor mounts. As mentioned previously if I pull those washers out the engine won't move forward at all because the front ear is already hard against the motor mount.

So looking at this some more, do I have small block motor mounts rigged in here?

Another view

I believe these are the mounts I should have?

Looking at your last picture, it seems that your mounts are on the wrong side of the block ears.

Do you have truck manifolds (center dump) or car manifolds (rear ish dump)?

Center dump on the manifolds.

The very last picture I have is of a big block mount bracket that I found on the internet. It’s the same as the Bouchillon big block mounts. Different than the ones on the truck now.

It sure looks like they cobbed that one. The whole deal was a cobbled mess. If I were you I would buy the correct mounts. Pull the engine and do all the freeze plugs. In the long run you will be a lot happier. Years ago I did and also seen others do what you are doing and in the end wish they were all done the first time. Pull it de-grease it, plug it and paint it. I would even toss a set of valve seals in it.

Call these guys. mounts

I have a 400 out of a truck on an engine stand. The picture of the left side looks correct. It will have a small cut out for the oil pump relief as well. The right side mount will mount on the front side of the ears. The RH mount also has a small offset towards the front.

Do you have any pics of the mounts?

Your mounts apoear to be on wrong side of mounting lugs and also look like 2wd mounts. Do they have a bend in them like the ones attached to the bare block?

Nope, no bend. The ears on both mounts are straight.

Looking at the difference in the mounts for 2WD and 4WD on Schumacher's site it does appear that my truck has 2WD mounts cobbled on it.

Found this on an old moparts thread.

Sorry, my computer was being a pain in the you know what, just shows up as black square nothing. Can't upload pics from my table, or my phone. Awesome. Anyways....

The Schumacher mounts look like they would work, but the right side mount has quite the offset. This may be so you mount it to the back side of the block ears. The left side mount, you can see the hole for the oil pump relief.

The FSM looks correct, as to mount on the back of the block ears.

I have a big block short shaft 727 from a low mile motorhome. It is not the funny kind with the parking drum.

It might be good to go with a quick service, the RV only had 43K miles on it. And was in operable condition when the 440 was extracted.
I however did not ever drive the RV so I cannot swear that the transmission was in perfect condition, but my neighbor (who bough the RV for the motor originally advertised as a 360, but he took it because he knew it wasn't and the price was right) is a Mopar guy, a friend, and has never given me reason to doubt his word.

If you are ever in Southwest Iowa, or have someone in the area that could pick it up, I would sell it for $100 which is below core price, since I cannot swear to the internals being operational, I cannot ship it though. After my truck wreck many years ago, I am no longer able to lift, move, palatalize, etc. any heavy objects.

I'm about 90 minutes South of Omaha Nebraska. Feel free to PM me if you could use this transmission. Hopefully this post is OK, its not actually a for sale, but more a trying to help a guy out posting.

Thanks but I had the trans rebuilt and had the correct tail housing put on it.

I have the correct motor mounts coming from Bouchillon and will pull the motor this weekend.

Also, having the cab fuel tank boiled and sealed. Was a rusty mess, another thing the previous owner lied to me about.

who is doing the tank? Local?

Thomas Radiator in Elyria.

Got the nasty lump of grease out of the truck. Now time to clean it up and put the correct brackets on it. A helpful board member is setting me up with a a 4bbl spreadbore intake on the cheap so going to put a new Edelbrock 650 on it with electric choke.

Pics show the mickey mouse engine mounts. Also, what is truly the dirtiest engine I've ever messed with.

As suggested, I'm going to replace valve seals. Since I'm this far wondering if I should just yank the heads to do so. That way I can check out the cylinders. The engine ran ok before I yanked it, some smoking at start up but otherwise ran smooth with no noises.

If it ran real good before I would just replace the valve seals. The one thing you could still do is remove the rockers and plugs and do a leak down test.

The more you take apart, the more you're going to fix. Before you know it, you'll have it down to a bare block! I know it's hard to leave good enough alone.

The Edelbrock carb will probably need an adapter to fit the intake. Does Edelbrock make a spread bore carb?

That motor isn't too bad, at least you can still see the bottom row of head bolts. The intake ports are very oily, which would indicate to me the bottom of the intake gaskets were probably leaking. The oil on the outside is pretty standard big block stuff, especially the ones with the factory hipo exhaust manifolds they cook the cover gaskets. Buy the high temp valve cover gaskets, or you will get real good at changing those gaskets.

I think, were it me, I would see how much slop the timing chain & gears have. Pop the dist cap off, and rotate the motor in one direction for a short distance, then stop, mark the rotor position, and change the direction of rotation and see how many degrees of crank rotation you get before the rotor moves. There should be very little distance, if it seems like a lot, I'd pull it down and change the timing chain and gears. Those 2 bbl big blocks came with a plastic coated cam gear and time is usually not good to them, the miles don't seem to be a problem until the mileage gets near the 100,000 mile mark. Over time, the plastic gets hard and starts to break off and the timing gets sloppy and the plastic tends to plug up the oil pick up screen.

Intake gaskets, timing chain and gears, and the oil pump pickup screen are the things that most concern me about the old big blocks. The valve seals would be somewhere down the list, but those seals are a lot older then they were when I was playing with a big block. Gene

I pulled 360 from my '79 W150 to get to those two rear freeze plugs, and did them all. It was either pull TC or pull engine. Did all freeze plugs, timing chain (dbl), intake gasket, valve covers, valve seals, water pump, and left every else alone. It ran well before but leaky. Mainly wanted to get those freeze plugs, did the other stuff while out.

ruderunner I'll need to get an adaptor plate for mounting square bore onto spread bore. I'll also need to figure out the kick down linkage. If you are around this coming weekend I'll run by and get those parts.

poorboy I planned to check the timing gear, I just may yank the water pump housing and timing cover and replace chain if needed. I'm replacing oil pan gasket so might as well do timing cover gasket.

I'm yanking all of the A/C stuff so I'll need to come up with some alternator and power steering brackets and maybe a crank pulley.

Also discovered that the front core plug on one of the heads seems to be filled with epoxy.....

That would be one way to stop the core plug from leaking.

Well I’m done taking things apart now I’m on to putting it back together.

as long as yer this far: hi vol oil pump.

given the choice between epoxy and rubber, I'd go epoxy.

too late now but there's a guy in the ads section selling truck mounts - lots of pics of the different styles.

skip the adapter plate, scrounge up a TQ

a/c delete alternator brackets will be a fun hunt. try face book, lots of parts trucks there.

I generally use air to keep the valves shut when doing seals. Also a decent way to check if they're closing all the way / cracked. Last big block I did had enough carbon built up to keep a few of them part way open. Pulled them all and chucked them in a drill to clean em up.