Grinding metal in my 80 drive train (1 Viewer)

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Joined
Jan 5, 2006
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Location
Philadelphia, PA, USA
I might need a transmission. Started out as a grinding noise when I was on the highway. Came out of nowhere.

Was doing 70 and hear the noise which I think was coming from the front right tire area. I started to lose power, couldn't keep speed, so I pulled over. Looked everywhere, no fluids, everything looked okay from the surface. I started it back up and the grinding was there, but I drove home at 30mph, no issues, everything performed, trans shifted etc...

I take to my mechanic, he pulls the wheels, transfer case covers, nothing so far. All clean.

Now though, when you start the truck, and put it in gear, I hear a grinding and it doesn't move. Just a grinding. I tried center dif lock, nothing.
 
What did the ATF look like? When my transmission went the fluid was almost black.

Could be diffs.
 
Put it into low then into drive. See if it sounds the same. If it moves try hi again. If it doesn't move could be the t case.
 
Still waiting on my mechanic, he checked the diffs, breaks all good. The transfer case was just drained and chunks of metal where in it. So we know that's shot, assuming the trans is good at this point. I think the trans is good, there was fluid in it and it never acted up before. So assuming its the transfer case....

What are my options, I see a lot out there, but I trust you guys. It's a 1991 FJ80 with 33's on it that will eventually have 35's, but that will be it on size. It has center factory and ARB rear locker, will eventually have front. This truck was for trips to go camping, fishing, hunting. What are your thoughts on what I should replace with?
 
It's not your DD right? Pull the transfer case and see what's chunked. If you're lucky you can just clean it up, put in new bearings and swap in the Terrain Tamer lower low gear and underdrive high gear. @OTRAMM did mine and I'm super happy with the results. You'll end up with 3.3:1 low gear and 10% underdrive which just about makes up for 35s. 33s might even feel down right peppy. Of course mines a 1FZ.

Worst case you pull the transfer case, open it up and more than the gears you're gonna replace are damaged and you have to find a used replacement. You could still take the opportunity to swap gears. I have a used transfer out of my 80 with low gears but I don't know if it's different than what's in a 91.
 
I know nothing about a part time kit. But I know low gearing. It's not cheap but will give you more control in technical terain. I like the sound of the under drive too. Kind of like regearing your axles but not.
 
It's not your DD right? Pull the transfer case and see what's chunked. If you're lucky you can just clean it up, put in new bearings and swap in the Terrain Tamer lower low gear and underdrive high gear. @OTRAMM did mine and I'm super happy with the results. You'll end up with 3.3:1 low gear and 10% underdrive which just about makes up for 35s. 33s might even feel down right peppy. Of course mines a 1FZ.

Worst case you pull the transfer case, open it up and more than the gears you're gonna replace are damaged and you have to find a used replacement. You could still take the opportunity to swap gears. I have a used transfer out of my 80 with low gears but I don't know if it's different than what's in a 91.

I like the idea of the lower first gear, but I cruise long distance in it and don't think I want to lower the overdrive, unless I'm not understanding you.
 
Why go to part time?
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I like the idea of the lower first gear, but I cruise long distance in it and don't think I want to lower the overdrive, unless I'm not understanding you.
All the options are available now, you can get tcase gears to make your low, lower AND leave your high range unchanged, higher or lower.

This has become an excellent opportunity to re gear w/o having to touch the diffs.

I can tell you from experience with my white '91, if you are going to "35s you will want lower/lower.

And some serious attention/preventive maintenance to the brake system!
 
If you never plan to go out west in your 80 then you're probably fine keeping the stock high gear set but I've read horror stories of people trying to climb moderate grades on 35s with stock gearing going 25 in second with semi trucks passing by. The under drive high gear set helps this by increasing RPM for any given speed putting you higher in the power band. Think of it this way, you've already modified your final drive ratio to the ground by running 33s thereby lowering your RPM at a given speed relative to the stock 31" tires. The under drive high gear just puts you back closer to a factory RPM/speed power band when running 35s.
 

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