'86 Jimmy 4in Lift, 40’s, tons, 8.1 Swap- 700r4 said PNNNNN

[GWeakland620]

Here’s a video synopsis from a buddy that was there. I ended up breaking both driveshafts at different times. Blew out the rear then took out the front trying to get back to the trailer. We ended up stealing the rear slip yoke and put it on the front shaft since the front u-joint blew up. Robbed Peter to pay Paul and was able to still drive it up on the trailer.

It’s a Facebook video, so I’m trying to save it and post it here so it can be viewed without FB.

He sent me the footage so this should work.

This was one of the first trails we hit. Nothing crazy, just exploring a bit.



View attachment IMG_0103.mov

Then we started hitting some tougher stuff. The truck was working amazing.

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This is where the rear shaft broke. Had already pulled up on it once, then took a break and let a couple others give it a try. After 3 other guys made it, I was determined to make it lol. I caught a bad bounce and the weak link gave in.

View attachment IMG_0978.mov

The plan moving forward is to upgrade all joints to 1410 and find the next weak link.

 

[folkenheath]

You can't have too much torque or HP, you can only have too weak of drivetrain to handle it.

 

[GWeakland620]

Some more pictures are still trickling in.

This picture shows the angle of the ledge where I broke the rear driveshaft.

 

[GWeakland620]

So a few years ago, James from Iowa and I traded 205 t-cases. I had a ford he needed and he had a GM I needed. Well, in the process of meeting up to swap cases, I forgot to grab everything that James brought with him. Fast forward to last weekend when we met up to wheel, he brought the rest of the trade with him that I had forgotten about. He had a 32 spline kit for the GM 205 that I snagged from him.

So that being said, I will be mounting the 205 behind the 4L80 when I start that process. I have a buddy with a machine shop that said said he can hook me up with machining the case for the bigger bearing. The end goal will be some sort of range box in front of the 205, but for now I am going to focus on the machine work and a full clean and rebuild of the 205 before I start the trans/t-case swap. And who knows, might snag a range box before then.

 

[GWeakland620]

Had a buddy that was doing a retube on the driveshaft I twisted which was the factory shaft for the Willoway Blazer. He surprised me and built me a new rear shaft for the Jimmy. Upgraded from 1330’s to 1350’s and .120 wall tubing. Should last a lot longer this time around.

 

[GWeakland620]

All painted up and drying. Plan is to toss it in tonight and then head to Heartland Motorsports Park for a grand reopening car show.

 

[GWeakland620]

Welp, I knew it was going to happen eventually. Got the new shaft tossed in Saturday morning and rolled out to the grand reopening of Heartland Motorsports Park car show. Had a great time and it was a great turnout.

When leaving the car show about 2 miles down the road, I started hearing what sounded like some sort of gears popping. I pulled off to the side of the road, and realized I had no forward gears. Messed with the trans and t-case shifter for a while and then realized I had no reverse either. I tried the t-case in 2, 4hi, and 4Lo and nothing changed. The front and rear driveshafts were locking with each other and unlocking like they should. Fluid on the trans dipstick looked nice and red with no metal flakes. Not real sure what to think. Called the wife and she came to the rescue. Flat towed it back to the house and messed with it again. No shifter cable issues. Linkage is all where it should be. Fluid level looks good and in good shape. Not sure what to think.

So the plan is to start the 4L80 swap later this summer. For now it sits and waits.

 

[imiceman44]

Welp, I knew it was going to happen eventually. Got the new shaft tossed in Saturday morning and rolled out to the grand reopening of Heartland Motorsports Park car show. Had a great time and it was a great turnout.

When leaving the car show about 2 miles down the road, I started hearing what sounded like some sort of gears popping. I pulled off to the side of the road, and realized I had no forward gears. Messed with the trans and t-case shifter for a while and then realized I had no reverse either. I tried the t-case in 2, 4hi, and 4Lo and nothing changed. The front and rear driveshafts were locking with each other and unlocking like they should. Fluid on the trans dipstick looked nice and red with no metal flakes. Not real sure what to think. Called the wife and she came to the rescue. Flat towed it back to the house and messed with it again. No shifter cable issues. Linkage is all where it should be. Fluid level looks good and in good shape. Not sure what to think.

So the plan is to start the 4L80 swap later this summer. For now it sits and waits.

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Did you check the transfer case fluid? Mine was almost empty.
Did you try low 4x4 then back to hi?
Mine was popping out internally in the np208, and by going into 4x4 low then back to 2wd hi it worked again.
It keeps happening every time I do a hard stop but I already have a replacement ready for when I have time to change it.
Just check

 

[Blue85]

Did you try low 4x4 then back to hi?
Mine was popping out internally in the np208, and by going into 4x4 low then back to 2wd hi it worked again.
It keeps happening every time I do a hard stop but I already have a replacement ready for when I have time to change it.
Just check

I had the same experience with worn shift forks.

I started hearing what sounded like some sort of gears popping. I pulled off to the side of the road, and realized I had no forward gears. Messed with the trans and t-case shifter for a while and then realized I had no reverse either. I tried the t-case in 2, 4hi, and 4Lo and nothing changed. The front and rear driveshafts were locking with each other and unlocking like they should. Fluid on the trans dipstick looked nice and red with no metal flakes. Not real sure what to think. Called the wife and she came to the rescue. Flat towed it back to the house and messed with it again. No shifter cable issues. Linkage is all where it should be. Fluid level looks good and in good shape. Not sure what to think.

Does the fluid level go down when you start the engine? If you just broke the pump ears, it might run again just by swapping the pump. If the T-case is in neutral and the trans is engaging, shifting from D or R to P will chatter the parking pawl.