Diff

Furb · February 02, 2011, 07:52:31 PM

well actually being an engineer made me cheat :Giggle:Hammer
because i KNOW how gears need to be aligned, in my previous job i did a lot of that in gearcases of factorysize printing presses.
i did NOT measure the gears in the diff, because i dont have the tools to do it at home. i just went with gut feeling..
but when I took the wrecked diff out, the wearmarks on the gears were perfect!

Ricco_04 · February 02, 2011, 07:56:54 PM

Well if you dont have the tools then I guess I definately dont! Better get a quote to get it setup and cheat my way! :Nono! (Gut feeling for me may end up in a "oh bugger, thats not ment to do that" moment

Furb · February 02, 2011, 07:58:30 PM

haha yeah, then we have another "clunking/rattling noise in the rear" topic :rollin

TiddlesRX7 · February 02, 2011, 10:37:03 PM

Is it not just a case of marking everything up before you strip it. Then rebuilding it to suit making sure you align everything up again? Making sure there is no play or tight spots in it.

Furb · February 02, 2011, 10:39:39 PM

well, in fact it is..

but as you replace the entire diff with another unit, the alignment is not exactly the same as it was before. there are always minor differences

TiddlesRX7 · February 02, 2011, 10:50:28 PM

Thats what I thought. So just to clarify then. You can use everything from the TII diff, half shafts etc. All you do is split it an pop the FD internals in the way the FC ones came out. Put it back together and fill it with oil.

Prof · February 02, 2011, 11:40:50 PM

It does look like you could replace the actual diff unit with the one from the FD - and just unbolt the ring gear from the FC diff and put it on the FD torsen - then your pinion gear will mesh nicely.

Does the torsen have the same number of splines as the FC unit then ?

Ricco_04 · February 03, 2011, 01:43:17 PM

Quote from: TiddlesRX7;740358Thats what I thought. So just to clarify then. You can use everything from the TII diff, half shafts etc. All you do is split it an pop the FD internals in the way the FC ones came out. Put it back together and fill it with oil.

Depends what series FC you have as the stub shafts can be different lengths

Ricco_04 · February 03, 2011, 01:44:23 PM

Quote from: Prof;740371It does look like you could replace the actual diff unit with the one from the FD - and just unbolt the ring gear from the FC diff and put it on the FD torsen - then your pinion gear will mesh nicely.

Does the torsen have the same number of splines as the FC unit then ?

Yes it all just swapps over (stub shafts aside) As in another post, the real work is setting it up properly

L18M · May 06, 2011, 11:52:44 PM

actual diff?? as in just get a fd diff (pumpkin with fd bits in it)?

whats a ring gear? crown?

then just chuck into an fc tii 1990?

whats this thing about lining / marking points?

sorry if they dumb questions and have been answered before.

infernal · May 19, 2011, 01:10:16 AM

The first three of your questions are answered in the first page of this thread.

As for the lining/marking points, after you install the diff and before you assemble the case, you need to set the backlash and tension. First you set the tension by screwing in the two rings and then you set the backlash by screwing both rings at the same amount towards the same direction. You go by the FSM. You will need a dial gauge (micrometer) and gear marking compound, to test and verify afterwards that you have it set correctly.

Basically what you are trying to do is keep the bearings under slight load to each other so that when the torque path changes (pinion to ring and ring to pinion) the carrier won\'t shock around. Backlash is set to ensure that the pinion and ring teeth mesh correctly, that is at the center of the area of each tooth.

Prof · May 19, 2011, 07:53:19 AM

Quote from: infernal;763501The first three of your questions are answered in the first page of this thread.

As for the lining/marking points, after you install the diff and before you assemble the case, you need to set the backlash and tension. First you set the tension by screwing in the two rings and then you set the backlash by screwing both rings at the same amount towards the same direction. You go by the FSM. You will need a dial gauge (micrometer) and gear marking compound, to test and verify afterwards that you have it set correctly.

Basically what you are trying to do is keep the bearings under slight load to each other so that when the torque path changes (pinion to ring and ring to pinion) the carrier won\'t shock around. Backlash is set to ensure that the pinion and ring teeth mesh correctly, that is at the center of the area of each tooth.

Fantastic explanation - I read the FSM and really didn\'t understand it at all!

This gear marking compound - does it require the internals to be free of oil (as in clean) in order to work?

infernal · May 19, 2011, 05:59:51 PM

Quote from: Prof;763517Fantastic explanation - I read the FSM and really didn\'t understand it at all!

This gear marking compound - does it require the internals to be free of oil (as in clean) in order to work?

Hehe sometimes the FSM is ommiting valuable information and just sticks to the numbers... But for DIY numbers are inadequate!

As for the gear marking compound, I sprayed and wiped the ring gear (nothing else) with a bit of brake cleaner prior to applying the compound, just to be sure.
Also after I finished, I removed the leftovers of the compound with a soft copper brush and I flushed everything with the old diff oil I had removed before.

The compound makes small chips and I didn\'t feel like letting it sit inside. Some people tell me that they don\'t wipe it or clean it at all and there is no problem, but to me it feels wrong, especially for the torsen and the bearings. :Thumbs-up