FJ40 FJ60 third members on FJ80?

[floridan surfer]

I may be able to source third members from a FJ60 with 3.70 gears.

Will the third member bolt into the FJ 80 axle housing without issues?

Pat

 

[LT]

The rear is no problem but the front you cannot. The front third is a 8" reverse ring and pinion while the rear is a standard LC 9" third.

 

[cody c]

The rear is no problem but the front you cannot. The front third is a 8" reverse ring and pinion while the rear is a standard LC 9" third.

I had to swap the stub end of the driveshaft from the 60 as well to use the 60 third in the rear, it wont/dont match up with the bolt pattern on the 60 pinion, also the 60 and 80 pinion splines are different so you cant swap the pinion flange from an 80.

edit: because the front is an 8" and the domestics only came with 4.11's (as far as I know but maybe Onur can tell otherwise) you will have an issue with finding a R&P for the front.

60 series front diffs are 9.5" diffs compared to the 80's 8" front,

mini trucks came with similar sized diffs but they werent high pinion,

the only 3.7 gears for high pinion 8" 80 series front were in JDM market diesels, but if they exist you may find parts from domestic dealerships or foreign.

 

[LT]

I had to swap the stub end of the driveshaft from the 60 as well to use the 60 third in the rear, it wont/dont match up with the bolt pattern on the 60 pinion, also the 60 and 80 pinion splines are different so you cant swap the pinion flange from an 80.

You can clock the bolt pattern for the drive shaft 90* and drill new holes instead of swapping out drive shafts and pinion flanges.

 

[cody c]

You can clock the bolt pattern for the drive shaft 90* and drill new holes instead of swapping out drive shafts and pinion flanges.

I think the centers were shaped so they wouldnt line up, like there was a lip on one of them that wouldnt let it sit flat, its been a while though so i cant remember exactly, but I seem to remember looking at that first.

Have you done this yourself?

 

[floridan surfer]

Ok. So what I'm gathering, the front will be a no go even if I were to attempt to install just the 3.70 gears themselves in place of the current 4.10.

Would I expect any issues if I were to do a gear install in the rear?

Pat

 

[Godwin]

I had to swap the stub end of the driveshaft from the 60 as well to use the 60 third in the rear, it wont/dont match up with the bolt pattern on the 60 pinion, also the 60 and 80 pinion splines are different so you cant swap the pinion flange from an 80.

Later year FJ60 (ca. 85 +) and FJ62 diffs would be a direct swap and driveshaft and diff flange patterns will match. I have swapped an '88 FJ62 driveshaft into a '97 FZJ80 and I've used an 80 series rear diff in an '86 FJ60. This applies to the rear only for the 80 series.

 

[floridan surfer]

Okay, The FJ60 is an 87 model. So based on the above post, this rear third member should bolt right up?

Pat

 

[floridan surfer]

Thanks to all that responded. I had a look at the thirds today. They are from an imported 60 and both front and rear were 9.5". Oh we'll, guess I'll keep looking.

Pat

 

[Tapage]

swaping the 60 series 3.70 rears and sourcing form Mr. T front 3.70 8" HP reverse cut will make the deal ...

 

[brian]

They are from an imported 60 and both front and rear were 9.5". Oh we'll, guess I'll keep looking.

Pat

pretty much like EVERY other 60 series in the world.

 

[BoxYourEars]

Just wondering why you would want to go to taller 3.70 gears in lieu of the stock 4.11s? Lower RPM's at highway speeds? Seems like an odd swap to me...please esplain my friend.

 

[inkpot]

pretty much like EVERY other 60 series in the world.

And FJ 40. and FJ 55......

 

[inkpot]

Just wondering why you would want to go to taller 3.70 gears in lieu of the stock 4.11s? Lower RPM's at highway speeds? Seems like an odd swap to me...please esplain my friend.

Got a feelin it has to do with the 4BT engine swap. He could always go with rubber overdrive, if he hasn't aready. JOhn

 

[cody c]

Later year FJ60 (ca. 85 +) and FJ62 diffs would be a direct swap and driveshaft and diff flange patterns will match. I have swapped an '88 FJ62 driveshaft into a '97 FZJ80 and I've used an 80 series rear diff in an '86 FJ60. This applies to the rear only for the 80 series.

The one I used was from an 82 or 83, so maybe the splines changed for 85.

Good to know.

 

[cody c]

Ok. So what I'm gathering, the front will be a no go even if I were to attempt to install just the 3.70 gears themselves in place of the current 4.10.

Would I expect any issues if I were to do a gear install in the rear?

Pat

You could do the 3.7's just in the rear, but as soon as you put it in 4wd your cruiser will want to break the weaker of the two.

Get yourself a late 60 series (85+) rear 3.7 diff, and then you will either need to source 3.7 front 80 series diff or gearset from toyota, or try and find a used set from overseas (australia japan etc. as they had 3.7's apparently in some of their diesel 80 series)

 

[floridan surfer]

Just wondering why you would want to go to taller 3.70 gears in lieu of the stock 4.11s? Lower RPM's at highway speeds?

This

Pat

 

[Godwin]

The one I used was from an 82 or 83, so maybe the splines changed for 85.

Good to know.

Maybe you mean flange pattern instead of splines. Flange patterns changed over the years but from 1979 (?) on the pinion gears have had fine splines. Flanges can be swapped around if needed to match up with the driveshaft flange pattern.

 

[floridan surfer]

The rear is no problem but the front you cannot. The front third is a 8" reverse ring and pinion while the rear is a standard LC 9" third.

I'm just realizing that I misunderstood this whole thread... It's the 80 series that has to different sized diffs, I thought this applied to the 60 series. So I guess I lost out on those thirds.

Pat

 

[floridan surfer]

Later year FJ60 (ca. 85 +) and FJ62 diffs would be a direct swap and driveshaft and diff flange patterns will match. I have swapped an '88 FJ62 driveshaft into a '97 FZJ80 and I've used an 80 series rear diff in an '86 FJ60. This applies to the rear only for the 80 series.

What about a 83 fj60? Think there would be any issues with the flange Match up onto the 80 series?

Pat