That new engine must be putting down quite a healthy bit of power. At least you found the cause, now it's time to get to it.

 

Just to update the thread. I was able to fix the issue. My rear u-joint was about to fall apart. and the Pinion Yoke was loose. I tightened it back down to spec, and replaced the U-joint. No more vibrations...Nice and smooth. Ran her up to 75 mph and was smoother than my Jeep lol. I did check the driveshaft as well. It was straight as an arrow. I still will replace the double cardan U-joints as well. Thanks everyone for your thoughts and opinions.

 

Here are some pics.

The powder were at one point the bearings.



the cap and toasted bearings were eating away at the joint itself.

 

Jeeze that's worse than mine!


A few of mine had no needles and dust in them, It was pretty scary. It's a good feeling knowing your driveline won't get seriously damaged.

 

Haha, those look like how mine were last year. I was hearing some squealing but not all the time. Didn't have a vibration though but when I went to check the driveshaft (specifically the double cardon joint), dust came out of one of the U-Joints at the cardon joint. I ended up having to replace the double cardon joint too because it was missing a roller pin and I know that would only lead to fun soon on down the road.

 

I never got the typical squeaking when U-joints start to go lol. I checked the U-joints in the double cardan. No slop and they move freely still. But I plan on replacing/rebuilding it just cause. And I assumed my front axle was bad cause it sounded like it was coming from there. So I've lucked out on saving quite a bit of money. My only issues now with the 4wheel drive is figuring out how to adjust the linkage and getting the 4WD indicator lights on the dash to work.

 

Hmm I don't know much about the linkage for the 4wd or the lights. I'm assuming you have checked the bulbs and they are good already. Do you have manual 4WD or auto? I know when I had to take my transfer case down and mess with the linkage stuff (going to the 4wd shifter) it didn't look like there was much adjusting I could do with any of it. I wasn't really paying too much attention to that though because my goal was replacing the clutch/slave cylinder in the transmission when I was taking that off.

 

I have the manual shift 4wd...When the lever is in 2wd...the front axle is still engaged. There is no engagement feel between 2wd and 4hi...Like my Jeep, When I pull the lever from 2hi to 4hi...you feel that lock. If understand what Im saying. I dont have that in my Bronco...but I do when I go to 4lo. And It is very easy for it to pop out out of 4wheel and into a "neutral". One of the main reasons I dont wheel it.

 

Hmm are you 100% sure that its put in 2 hi? If the front driveshaft is still spinning, I'm pretty sure it's not out of 4wd. I know it's kinda a pain to get in and out of 4 hi from nuetral/2wd on my shifter. You have to press down on the lever and push it down to 2wd. It should make a click. it takes me a few times going from 4hi to 2hi to get it back in but I can always get it. I would check the fluid of the transfer case too and make sure it's red and has no metal particles in it. I changed my transfer case fluid last year and it was super dirty. I would highly recommend changing it if you have never done it.

 

If he happens to have an NP-203 x-fer case then his front drive line will always spin when the rear does. It's a full time transfer case. My 78 has one. This is the shifter pattern for mine. I don't know if it would be the same for all others but this is what it came with.


I just leave my front driveline off, so that the front wheels don't get any power. As for fluid I put gear oil in mine... I think you are able to use either light gear oil OR Type F. Whatever suits your fancy.

 

Oh well that's a bit different than mine then. I have a borg warner transfer case and the front drive line isn't engaged when the rear is. I like that a lot better, less moving parts so better gas mileage!

 

Ah, I don't know anything about Borg Warner stuff. I want to eventually put the NP 205 case in my 78. It's a part time gear drivven and the cast iron ones are next to bullet proof. If I really go crazy I would do the 203/205 doubler but I don't have a need for that much crawling power yet.

 

Yeah I am not too familiar with any of the transfer cases really, I just kinda looked at mine when I took it down. I unfortunately don't use it as much as I would like because I don't like off roading by myself, but I think it a good transfer case for my needs! I wouldn't like having the front driveshaft in constant motion though, but I would rather have that then a 2wd for sure!

It sounds like the NP 205 would be super heavy if its cast iron. Maybe not though. I know mine wasn't too bad, I was easily able to lift it up and down full of fluid when I needed to get to the slave cylinder in the transmission.

 

Here is a blurry picture of my 203. It's case iron and about X2 the size of a 205 cause it's chain driven.


205...


Now if I unbolted the front of the 203 off and slapped it on the 205 with some modification, it would be considered a Doubler. That's a 4:1 gear ratio vs 2:1 of each.

 

I have a BW1356 t-case. It's been awhile since I've really looked at all the linkage and everything. It doesn't help that my truck is a cross-over/ Ford half year model switch. I'll get it all figured out...just have to really sit down and get into it.