Ford Diff Identification

[Guest Jomeo69]

afternoon all.

Been a bit quiet on the front recently due to a couple of things.

Work as per usual oh and the body off restoration of our marcos mantula.

Anyway we were wondering which diff is on it and dragged the numbers off.

 

83BG-4033-BA

 

D04 BA

 

have looked on the locost builders site but couldnt translate.

If anyone knows what car this diff is from that would be great.

Or knows of how to translate the locost site that would be amazing as well.

 

Many Thanks as always.

Joe

[Guest Ian & Carole]

85GG 4006 DC --- 3.97

85GG 4006 BC --- 3.62

85GG 4006 AC --- 3.38

85GG 4006 FB --- 3.36

87BG 4006 GB --- 3.14

 

V87BG 4006 CAA ---3.38 LSD

85GG 4006 AAA --- 3.36 LSD

V87BB 4006 BAA --- 3.62 LSD

86GG 4006 AAA --- 3.92 LSD

 

are diff specs from the alli tag.

 

I think you are looking at the numbers that are cast on the case its self and is just the casting number, used, I belive, on all 7" diffs.

[Longboarder]

As Ian says the only useful number is on an ally tag held by one of the rear cover bolts. They usually corrode away to dust. If so then remove the eight allen bolts that hold on the rear cover. Give each one a sharp whack or two with a hammer to free off the steel/ally corrosion and remember to put an oil tray under to catch the stinky oil. Uncle Henry kindly writes the diff ratio on the outer edge of the wheel and you can also see if it's an LSD. This ones a 3.62 LSD.

 

Nigel

[Guest janis]

I have a same diff..if i jack back of the car up and turn one wheel other one turns opposite way..is that means i have open diff?sorry for stupid question..

[Guest 2b cruising]

I have a same diff..if i jack back of the car up and turn one wheel other one turns opposite way..is that means i have open diff?sorry for stupid question..

if you turn the prop shaft and both turn the same way, you have a LSD

If the diff is open, or non LSD they should turn opposite.

[Snapperpaul]

Super 7th Heaven site has all the info you'll ever need, he has converted Ford Microfisch

But boy is it a difficult site to look at on an iPhone

[cb750]

An excellent site, I always have a look at this one first if I need info.

[Guest janis]

I was looking from my phone that site but coud not find my numbers.

[Longboarder]

The numbers on the castings are just numbers for that casting. The number that tells you what is in the diff was on a thin ally tag held by one of the backplate bolts. This ally tag corrodes away on almost all diffs. The best way is to open up the diff and read the white marker numbers off the edge of the big gear. If you do this you can also see the bigger gubbins the big gear ring is bolted to which tell you if it's an lsd or open diff. The open diff has a single piece gubbins. The lsd gubbins is obviously two rings sandwiched as you can see from the pic.

 

Nigel

Edited April 25, 2015 by Longboarder

[Guest Ian & Carole]

I was looking from my phone that site but coud not find my numbers.

 

Have a read of post # 2 on this thread if you have the alloy tag if not then like longboader sat open up and read numbers on crown wheel.

You can also turn the pinion and count the number of rotations of the out puts.

 

[Guest janis]

Ally tag is corroded..dont really open up my diff just to see whats inside was just wondering what diff i had..whan side of diff leaking oil..is the seals hard to change?what oil i put in that diff?

[Guest Ian & Carole]

If you really want to know what ratio you have jack car up and place it n stands, Put a blob of paint on your pinion/ prop shaft and rotate one of the road wheels through two full revolutions and count the amount of times the pinion turns.

 

more than 31/2 it will be a 3.6

nearly 4 rotations and it will be the 3.9

 

HTHs.

[Guest 2b cruising]

 

 

I would hope that of you turn the propshaft both wheels turn the same way no matter what diff you have....

 

I believe it is shown by jacking the back up and turning one wheel and the other wheel turns on the opposite direction for open diff or the same direction for lsd.

how very strange.

I have just been and fully tested your theory in my shed.

I have recently bought a LSD for fitting to mine after the engine conversion.

Turn one output flange and as you said the other flange turns the same way.

Turn the input shaft and both output flanges, yes as I said turn the same way.

Here's how. If the diff is LSD and no resistance is felt by either side output, the diff as designed is not a diff but strait through drive. ie, as. In driving on slippy stuff, bothe wheels will give drive.

I hope if you have an LSD, they don't both turn opposite ways.If they do, you have worn out diff plats if it's of that sort.

 

Edited April 25, 2015 by 2b cruising

[Guest 2b cruising]

Also forgot. If on a jack and both wheels are turning the same way. What is the prop doing. It cannot stay unmoving as with an open diff.

If the transmission is locked out and enough force is used to overcome the resistance of the LSD unit, you should be able to turn one wheel and the opposite wheel will turn the opposite way.

However, if you test by turning the prop shaft it would be impossible to overcome the resistance because of lack of leverage.

This is why it is best to use propshaft instead of wheel.

Edited April 25, 2015 by 2b cruising

[brumster]

I've never tested one, but wouldn't a viscous type diff behave like an open diff at hand-moved speeds? Only when the viscous coupling is agitated enough would it start to lock?

 

Plate diffs a different matter. Unless the plates are knackered or the pre-load is incorrect, you should have both wheels turning in the same direction if you turn one of them - and if you pop one wheel on the ground and hand-turn the other, you should get resistance up to the pre-load setting, and then it should turn (with a bit of grinding noise, most likely ).