Mick's Diff Dilemma

[Super Jamie]

i have a friend called michael, he has a jap import ae71 panelvan with a jap import ae86 4age motor in it. it's a really nice clean car, and chops v6 commodores easily

 

mick recently bought himself a nice little late model ke71 for 500 bucks and has been driving it like he stole it. he lunched the diff this week (snapped a spider gear in half), so he pulled it all apart and went to the wreckers and got a new one that looked the same

 

i get a call friday to ask for some tips, and away the boys went to work on the car. they call me back this arvo, they've got the new diff center in, but it makes his god awful noise. mick took it for a strap but it sounded like there was a two stroke motorbike in the boot!

 

i go over and they've got the borg warner's inspection plate off, and it's definately not like a ke70 diff i've seen before. instead of everything being internal to the housing and a pain in the arse (like a ke55 bw), this one has two bearing carriers (like a crank bearing) and out the center pops, just leaving the pinion in the housing

 

we have a play around for a while, and i suggest it's gear noise, definately related to the pinion and ring gear. i was thinking perhaps they have vastly different clearances and aren't meshing as well as they could? we get the old center out, and the ring gear is held on by 6 bolts, mick suggests swapping the ring gears to change clearances. so out it all comes again

 

as we're fastening the center into a vice, i say "hold on, count the teeth. i've got... 35" mick goes "... 37" count again, 35, 37. aha! we swap the original 4.11 ring gear from the stuffed center onto the good center, and ditch the 3.9 that we got from the wreckers. bolt it all back up, and she spins beautifully. make a gasket out of a folder and permatex 3, put the old oil back in and bob's your uncle!

 

so i guess the pinion from a 3.9 and 4.11 in that series is different, unlike a jap U series where all the pinions have the same teeth, just different bearings. what's that diff called? it's definately not like an early ke70 diff. the wreckers said "nah we always see those in ae71s, you need this different center" and their suggested one was indeed the right one

 

another day, another corolla problem solved!

[Super Jamie]

i just got an sms - the binhunter is back :P

[Teddy]

Jamie - have a look at this

 

(scanned from my original 1982 sales brosure)

 

 

Note the final gear ratio figgures... :P !

 

weird ey ! lol

[Super Jamie]

is that an aussie brochure? you'll probably find the ones overseas had 4.3s, U series japanese diff like a ke30 (also had ke30 brakes on the front)

 

the ring gear we used had 4.11 stamped on the side of it, and i did maths and worked out the "wrong" diff was a 3.889. most aussie corolla borg warners are 4.11s