mystery shimmy

[studabaker]

Im gonna get right to the point first, and then provide story.

2001 expy xlt purchased 2012 and blew trans 2013 cheap swap for 1000 bucks and has not been the same since. He was upselling me to a eddie bauer transmission from a compatible year, I dont know if the wrong transmission was installed or a slight variation may be causing this problem???

At 65 mph it becomes more noticeable and it is felt to a lesser degree at slow speeds. I pulled off the next exit. In normal driving it is annoying however on a trip of several hours it begins to damage cv axles and front differential. first i swapped out a front differential and it was improved but not gone. It feels like a bearing and I have had shops do some tests and other work on it but cannot find the damage. I have done some work to so that is suspect I admit but has been ruled out by these tests. A moment of clarity was when it was felt and put in neutral and the motor rev to 3000. Occasionally when it (was) bad at 2000 rpms the engine really shakes and I have to slow down and crawl back. This lead me to misfires which I had but those are now resolved to the best of my knowledge. I got a torque converter a few weeks ago and it is improved but not the problem. I was sure. I plan on going through and locating the frame mounts or something to check the condition

I feel it in the front on acceleration a bit where there is flex in the driveline? or something is off slightly.

Tests:
continues to shimmy at 60 with engine in neutral and changing rpm yet constant shimmy?

transmission checks out with expert

engine checks out with mechanic

front differential checks out with long turns both directions test at near 60 when shimmy is felt.
In theory it would be worse on one side or the other.

It seems like there resistance in the front drive line after the transfer case.

transfer case swapped out for pulled one.

drive lines balanced

rear diff rebuilt

new wheels and tires

suspension checked out by 4 wheel store.

This seems to narrow it down to the transmission, or transfer case? mounts or ??

thank you for any help

 

[1955moose]

Well if all this shimmy started with a transmission swap, its got to be something bent, or goofy with that 4 r100 trans. I've got that same trans in my Eddie Bauer, but mine came from factory. Not knowing the capabilities of installing mechanic, could be a lot of things. Drive shaft issues usually start around 50 mph and gets worse at higher speeds. Be sure axles front and rear aren't bent. Have drive shaft checked off vehicle by drive line shop. When you say shimmy, are you feeling it in steering at all. Report findings.

Sent from my N9131 using Tapatalk

 

[studabaker]

I have been researching the transmission and it turns out the eddie bauer uses the 4r70w transmission in two wheel drive models. Not sure if they had awd bauer edition. They may have used 4r100 sometimes. That leads to slight gear ratios differences for towing. I feel this is where the problem is. If the transmission is programmed for a 3.5 rear end and i have a 3.7 how much of a deal would that be and can i modify that without a new transmission? This theory doesnt really make sense because changing transmission shouldnt change gear ratios or have anything to do with that. This theory is what it feels like progressively worse starting at 55, until significant at 65. It does seem to accelerate at that point but cruising at those speeds and the front end is suddenly more out of balance.

Yes axles and driveline shafts balanced but that is what it feels like with wheel speed there is something not quite true.

I need to make sure i have the 4r100 in the first place. I would think that they would make them slightly different to prevent this type of thing. At least in the bolt pattern.

As far as capabilities of the mechanic, when they get served papers taped to the door, probably for being sued in civil court is not a good sign. Life lesson, i knew better. I did get back on the road and to an interview, no dice on that job, for only a grand. The transmissions alone are over 2000 bucks.

Thank you for your reply
Stuart

 

[1955moose]

So they installed a tranny out of a 2 wheel drive into a 4 wheel drive? Until now, I didn't even know they made an Eddie Bauer 2 wheel drive. Thought they all were 4x4. Learn something new everyday. Why not rack your vehicle, and observe the front end very carefully at speed. You should be able to observe something out of whack! A bent axle, wheel, loose suspension parts. A problem as obvious as yours should rear its head. That's what I would have done all along. I think your grasping at straws with the gear ratio difference. By the way I'm a big fan of early Studebaker pickups, what cars/trucks do you own. From your handle, I'm sure you have at least one. We used to have a Studebaker dealer here in Daly City where I live and grew up. I cried a tear when it got tore down, and they built apartments in its spot!

Sent from my N9131 using Tapatalk

 

[studabaker]

I nearly purchased a studebaker truck a long time ago. I like cars and would get one of those stepside bed. I rebuilt an eagle talon and working on a oil leak from my oil pressure sensor. I think i over tightened it. The expy was my used car dealership solution to car break downs. Ive rebuilt the majority of the front end suspension on my expedition trying to isolate it. I always knew what i felt but not really broken and some new vocabulary. Yea im in Sacramento so i know of daily city. I am ready to put up fifty dollars if someone knows what this is.

I agree that the differential gears ratios should stay constant with a new(used) transmission. It has been challenging to communicate the feeling and as if there was a .01 difference that only is significant at freeway speeds and the wheels have to skip to catch up the play in the line every few rotations and only in the front. I have sought experts and had good improvements and information from these people but they are stumped and i have no place else. Maybe i will use this to. Communicate my problem to a ford mechanic somewhere.

At 60 its independent of the rpms of the engine and shakes the front pretty bad.

Not misfire.

New torque converter. Working correctly.

Transmission shifting smoothly.

I am going to be looking into making sure everything is matched up correctly with the transmission swap. I believe i have the towing gears 3.7something which is the ring gear to the pinion gear im pretty sure. If there were different features they might have re pinned the connector, on a long shot.

If somebody knows what it is then it would be an easy fifty bucks reward.
Thank you
Stuart

 

[1955moose]

Nah, we don't take tips here! Just trying to figure out your problem. I don't what it is about Sacramento, but I never hear good things about that place, being are capitol city, I guess that says it all. You stated in your original post that you swapped out the front differential, and things improved. You didn't have these issues until transmission and torque converter were changed. Is your shimmy transferred to steering wheel? Or do you just feel the wobbly feel underneath you.

Sent from my N9131 using Tapatalk

 

[studabaker]

OK so I went to the transmission shop today and I had professionals put it up on four stands and run it in gear and see the vibration. the front wheels were wobbling like out of balance. We took the front drive line out and no more wobble in the front. I am scheduled to have front differential rebuilt next week, and this will give me time to think it over and talk with anyone who might have an idea.

Started after affordable trans swap, at a shady place. It was a garage where they had many engines and transmissions, likely from auctions.
(Sacramento)
The roads in Sacramento are rough and there is little around for hours, so come here and get your bushings beaten up and drive home a few hours up through the mountains and then through the desert. Then there's the shady people who will sell a broken car for full price. I should say shady used car dealerships. I went to Ford yesterday and they were no help.

So we are assuming that it is not the transmission because without the drive line it is virtually gone. There is something slightly not harmonious in my engine but it is very slight roughness above 1000 rpms when first starting.

The problem is clearly noticeable at 65 I feel it everywhere. It feels like if I were to go faster it will shake apart. It did shift down to another gear at 65, and I can go faster without failure but it does increase.

My friend 1955Moose I think I have cleared up some details. The torque converter improved but not cause. I swapped out front differential with a used one and improvement yet not the cause.

I am just not certain that because the front drive line is out that the transmission is completely ruled out for sure. I am reasonable confident that it is the front differential but I really don't know for sure is my dilemma right now. What that proves really is that when the front suspension is not connected to the transmission then there is no wobble so it suggests something behind the front driveline just as much as in front of it?

stu

 

[1955moose]

If you took off both front CV half shafts and wobble disappeared, you've narrowed it down to shafts, or something in the differential is bent or out of alignment. If you suspect a bent wheel, spin it on a wheel balancer. If I remember in your earlier post, you stated that you had new wheels and tires, but now the fronts are bent. You also swapped out both differentials. This ought to be fun what they/ you find. Let us know, I'll bet its something dumb, usually is!

Sent from my N9131 using Tapatalk

 

[studabaker]

Well drive line axle from transfer case to front diff. Technically. Removed and no vibration...

 

[1955moose]

So was it a bent axle? Sounds like it, or a bad joint.

Sent from my N9131 using Tapatalk