true520

Hey guys,

We traded around and got a 1987 Toyota 4wd with a 22R carb motor and 5 speed tranny.

This truck was being driven everyday with out the front Diff, axles, or shaft in place.

Everything has been painted over with black primer, so we couldnt tell exactly what gear ratio the rear end is.

After installing all the needed parts to make the 4wd system work (which we got from a local junk yard) The front end diff is binding up.

Of course, with the hubs un locked, it all rolls fine... But, if you lock the hubs in, it binds up with in a couple of feet... Even with the front drive shaft Not installed.
???
Sooo, would the rear gear ratio matter even if the front drive shaft is not installed?

Trying to determine if we picked up a bad front diff, or just have one installed with the wrong ratio.

Thanks again for the help

millball

Something is wrong in the front end.

If everything is alright in the front drive, you should be able to drive it, hubs in, or hubs out, regardless of mismatched gear ratios, with the front driveshaft removed.

true520

That's what I was thinking , but someone had mention the ratio maybe causing it.

Would it be just as easy to buy internal parts and re build it ...?

If so, where is the best place to find parts now.

As you can tell, I am not familiar with a Toyota at all.
LoL

millball

You should be able to determine from your trucks ID plate what the original gear ratios were. If the truck has not been modded with large tires/lift, ect., the rear diff may still have the stock gears. It is also possible to jack up one wheel, and turn the wheel one rev while counting the driveshaft revs. As I recall, the ratio revealed must be divided by 2 to get the correct result.
Maybe the wreckers where you got your parts will make it good if their stuff was bad right off. Brand new differential parts and labor are expensive. Good luck!!

true520

There is no tag on the rear end and the door ajms have been painted over too.

Im not sure why jacking up the drivers side rear wheel and counting the axle revs vs the tire revs didn't work for me either.

But the axle was only turning 2 full rotations to the Tire's 1 full rotation.

I even called my local Advance auto parts store and have him the vin#.
He said it is showing a 4:56 gear ratio.
But I really don't know what is in there now ??

highonpottery

iTrader: (1)

Possibly mix matched sets, especially if you got junk yard front diff without knowing what was in the rear, lol. Less likely a bad diff, but still possible - does it spin freely when disconnected from tcase and cv axles unlocked?

To determine rear ratio, put jack under one side (open diff only), put reference mark on tire and on pinion flange. Rotate tire 2 revolutions and count rotations of pinion. See specific directions here: http://www.4crawler.com/4x4/4R_TechInfo.shtml

To answer the title question - with front disconnected you essentially have a 2wd and no problems. Gear ratio only matters if trying to maintain "ideal" gear to tire size ratio.

true520

I am afraid we bit off more than we want to chew. LoL

I'm pretty sure we have a bad front diff tho. It binds up if the front hubs are locked up ... Even if the front drive shaft isn't even installed.

Now our biggest challenge has changed into figuring out what exactly is the rear gear ratio.

It is not marked anywhere we can find. Not sure how many parts have been added or changed out of this truck either. It didn't even have a front diff in it when we got it. LoL

toyota4x4907

An '87 with a manual trans would have 4.10s from the factory. Disconnect the rear driveshaft at the differential, if it is the original gears, the now visible end of the pinion gear should have color on it. I can't remember all the colors but PINK is 4.10.