Hoping ya'll can help me get my truck back on the road again. Any info or help is greatly appreciated.

I currently own a 1988 Toyota Pickup Reg Cab. The previous owner had converted the trans from 4 speed to 5 speed "just in case that might contribute to the issue". The truck was also lowered by the previous owner using 3" non tapered blocks in the rear, pulled one leaf, and torsion'd down the fronts.

This past weekend i decided to level out the truck by installing 4" angled blocks. After the install I immediately decided to go on a test drive and right off the bat I hear the drive shaft making a grinding noise and obnoxious vibration. I also noticed the truck starting to smoke along with a burning smell. Im not sure what the positioning of the drive shaft looked like initially with the 3" blocks but after the 4" block install I noticed the drive shaft is positioned less than a inch away from the gas tank. I also noticed slight rubbing marks on the gas tank and cross member.

However, to get the best point of view I ended up putting the rear end on jack stands while jacking up the rear diff to the normal "on road" height. Turned the truck on and put it in 1st gear to try and see if the drive shaft is rubbing against the cross member and or gas tank, but no sign of rubbing on either. What i did notice is at the far most front of the drive shaft that connects to the trans, there is this foil colored circular casing that surrounds the connecting point from the shaft to the trans. While the driveshaft is spinning i do notice that casing spins intermittently. Not sure if that is normal or not. Ive finally hit a wall and cant seem to figure out what the problem could be.....

As of right now im probably going to change out both U-Joints to start with.... Thank you in advance for taking the time to read this, any help would be greatly appreciated. I will also post pictures of how the drive shaft sits currently.

 

First off modify so that can not hit the fuel tank!!!

Sounds like the pinion angle is way off, & I take it you have a one piece drive shaft.

On my extra cab, with a two piece shaft, the fix was a double careen bearing at the front of the rear shaft & a slip joint at the rear.
If I was you I'd find a drive line shop to look at your truck & find the fix!

 

Thank you for the response man! I will definitely take those recommendations into account.

 

driveshaft hitting the crossmember right behind the cab is very common in regular cab trucks. Chope that fucker and see what happens.

i had the pinion bearing take a dump on me after installing blocks on my previous yota, hope thats not what going ok with yours

 

The crossmember seems like the common culprit according to everyone ive asked thus far. Im really hoping that will fix the problem. So you think anything above 3" blocks will cause the pinion bearing to crap out?

 

Nope not saying that. Just sharing an experience i had. And if the u joints and clearancing the crossmember dont work, id check the diff

 

Okay, gotchya. Thanks again dude!

 

The following photos have been taken with the truck on the ground and with the 4" blocks installed. Is it normal for the driveshaft to be that close to the gas tank? Also, that is how much room the drive shaft has from the cross member.

 

A picture says a thousand words...

Looking at your first and second pics, you can see rubbing on the drive shaft as well as the base of the yoke. I would start there.

When did your quick test of letting the engine idle in first gear with the truck in the air, was there anybody sitting in the truck and any load that reconstructs the the conditions when you hear the nouse?

 

Thank you for checking in dude! Aside from the driver, no one in passenger seat and bed of truck. I did notice the rub marks but is the drive shaft supposed to be that close to the gas tank in the first place?

 

The driveshaft is pretty close at normal ride height on my 73. I don't think you get much side to side movement with leaf springs. It can hit the tank if the bolts break. It has happened and I'm pretty sure that's what happened to my tank.

 

ahh i see. I guess that gives me a little peace of mind

 

I don't remember how close the tank is to the drive train. I know it's tight but I don't think it was that tight...

Something just occurred to me; is that an aftermarket auxiliary tank? Or was the stock tank stretched or relocated rearward? I have a 1988 long bed so there might be more space under my truck. But I don't remember anything being that far back and close to the rear axle or u-joints...

 

So after countless hours of diagnosing the issue. We finally figured out the problem. Because the truck was converted from 4-speed to 5-speed "by the previous owner", the only thing that he didnt change was the driveshaft. Currently the 4-speed driveshaft is too long for the truck to be lowered beyond 3 inches. The 4 inch angled blocks that I installed pushed the driveshaft too far forward into the trans causing it to bind at the spline. Not only did the driveshaft shift too far forward but also too far towards the passenger side where it was also rubbing against the gas tank. In conclusion I will be needing to find me a 89-94 single cab 2wd 5-speed drive shaft which is supposedly "shorter" than the 4-speed shaft. This will allow me to have the correct pinion angle while being lowered on 4inch blocks. Thank you to all those who chimed in earlier! Really appreciate ya'll input. Will take more pics and update you all after I get my hands on a 5-speed driveshaft!

 

I think you can get away with any 5spd single cab drive shaft that has the same wheel base, either way always measure. Good find!

 

Thanks for the info dude. I will definitely measure when I get my hands on one!

 

It's not hard to shorten a driveshaft I've done a few, most times it will not need balancing, Here are some how-to instructions.
https://www.garagejournal.com/forum/threads/shorten-a-driveshaft.56556/
I've also seen videos of guys cutting the shaft in the middle and welding it, I've never done it that way and I would think it would be a very bad idea.
The last shaft I did was on my shorty project which was a two-piece shaft and it worked fine without balancing
https://www.instructables.com/Rat-Rod-Rescue/

 

Man if you were in Hawaii, i'd definitely pay you to do it for me because you aint going to catch me near a welder LOL. Really appreciate the input though!

 

Lmao it's good that you know your abilities to not put yourself in danger but a welder is nothing to be afraid of. You may catch on fire or electrocute yourself but it's fine.

 

"Pushed the driveshaft too far forward". Is the angled face on the bottom (against the springs) or on top (against the axle)? If the angled face is on the bottom, try flipping the blocks so the angled face is at the top?