Which diff - locker?

beavy69 · Jul 13th, 2009, 16:51

I'm looking into changing the standard differential on my 740 turbo saloon (one piece rear axle not multilink) to either a LSD or locker. Due to an oily road I need to replace the whole back axle anyway. I've found that apparently all 940 turbos had a locker on them and that the I.D number should be say 1041. And it will fit my 740 so long as its the same final drive ratio, is that correct?

And would having a smaller/larger ratio just increase top end/acceleration or would it simply not work?

Finally, I've heard that lockers can be harsh and switch traction from wheel to wheel very suddenly. I want to start learning how to power slide/drift better so I've always got control (where there's a safe place to do it ;-) so would a LSD be better? And are there models that are a straight swap with an LSD I can use as I don't have to money to fork out for an aftermarket job, especially if a locker will suffice for what I want to do?

Thanks in advance, your knowledge is greatly appreciated, I'm fairly new to Volvos and totally new to RWD therefore don't know much about diffs!

cumbrianmale · Jul 13th, 2009, 20:18

If you want to drift you will need a LSD or will need to modify a locker.

The locker will distribute drive 50:50 if one wheel spins but only up to around 25mph. It works on centrifugal force to lock and someone with more knowledge will have to explain the mod required to get it to lock at any speed.

rogerthechorister · Jul 15th, 2009, 21:40

There are three axle casings - 1030 1031 and 1041. Some need a spreader to get the diff in and out of the axle.

There are lots of diff ratios from 3.31 (great on motorway) as far as (I think) 4.7 (wheelspin special!)

There are at least two traction control diffs - the torque biassing and the locker. If one of them isn't what is called the G80 then there is also the G80.

Locker totally locks - but as said above only up to 25 mph.

I think all the diffs are basically Dana diffs. At high powers most break the cross shafts in the diff. Modded ones do exist and I think also another mod that puts two cross shafts in place.

The diff details are supposed to be on a plate on the axle casing, but I have never yet found a way of getting aged underseal and crud off to read it without destroying the plate (or at least the writing on it) in the process.

I want two 3.31 torque biassing ones. Cash available.

beavy69 · Jul 23rd, 2009, 08:48

From what ive found elsewhere i think G80 is the locker. My Haynes manual says there is a clutch plated operated LSD in some models but doesnt give details, assuming this is the torque biassing diff you mention roger. Does onlyone know which models this can be found on and/or what the axle code is for one?

davebslater(uk) · Jul 23rd, 2009, 11:37

the locker is teh factory one , the clutch plate LSD is pretty rare , and can break easily , so the aftermarket choices are the dana trutrac and a host of lockers .

it really depends on your budget , the trutrac more like a normal car , the locker like a sideways legend

Jul 13th, 2009, 16:51	#1
beavy69 New Member Last Online: Mar 9th, 2016 11:24 Join Date: Nov 2008 Location: Dorset	Which diff - locker? I'm looking into changing the standard differential on my 740 turbo saloon (one piece rear axle not multilink) to either a LSD or locker. Due to an oily road I need to replace the whole back axle anyway. I've found that apparently all 940 turbos had a locker on them and that the I.D number should be say 1041. And it will fit my 740 so long as its the same final drive ratio, is that correct? And would having a smaller/larger ratio just increase top end/acceleration or would it simply not work? Finally, I've heard that lockers can be harsh and switch traction from wheel to wheel very suddenly. I want to start learning how to power slide/drift better so I've always got control (where there's a safe place to do it ;-) so would a LSD be better? And are there models that are a straight swap with an LSD I can use as I don't have to money to fork out for an aftermarket job, especially if a locker will suffice for what I want to do? Thanks in advance, your knowledge is greatly appreciated, I'm fairly new to Volvos and totally new to RWD therefore don't know much about diffs!

Jul 13th, 2009, 20:18	#2
cumbrianmale Forum Support Team Last Online: Jun 9th, 2024 14:30 Join Date: Mar 2006 Location: Deep in Makem territory	If you want to drift you will need a LSD or will need to modify a locker. The locker will distribute drive 50:50 if one wheel spins but only up to around 25mph. It works on centrifugal force to lock and someone with more knowledge will have to explain the mod required to get it to lock at any speed. __________________ Current 04 S80 D5 SE Auto 03 S80 D5 SE Man Previous Volvos 90 240 GL B230FB Auto 96 940 CD 13 V40 D2 R-design 89 745 GLE 98 V90 3.0 24v 98 945 Celebration Auto 96 965 SE Auto 86 744 GL 81 244 DL

Jul 15th, 2009, 21:40	#3
rogerthechorister Rogerthechorister Last Online: Dec 16th, 2023 02:15 Join Date: May 2006 Location: Rochester	Diffs There are three axle casings - 1030 1031 and 1041. Some need a spreader to get the diff in and out of the axle. There are lots of diff ratios from 3.31 (great on motorway) as far as (I think) 4.7 (wheelspin special!) There are at least two traction control diffs - the torque biassing and the locker. If one of them isn't what is called the G80 then there is also the G80. Locker totally locks - but as said above only up to 25 mph. I think all the diffs are basically Dana diffs. At high powers most break the cross shafts in the diff. Modded ones do exist and I think also another mod that puts two cross shafts in place. The diff details are supposed to be on a plate on the axle casing, but I have never yet found a way of getting aged underseal and crud off to read it without destroying the plate (or at least the writing on it) in the process. I want two 3.31 torque biassing ones. Cash available.

Jul 23rd, 2009, 11:37	#5
davebslater(uk) redbollock guru Last Online: Jun 30th, 2016 23:54 Join Date: Jan 1970 Location: lincoln	the locker is teh factory one , the clutch plate LSD is pretty rare , and can break easily , so the aftermarket choices are the dana trutrac and a host of lockers . it really depends on your budget , the trutrac more like a normal car , the locker like a sideways legend __________________ www.dbsmotorsport.co.uk

Jul 23rd, 2009, 08:48	#4
beavy69 New Member Last Online: Mar 9th, 2016 11:24 Join Date: Nov 2008 Location: Dorset	From what ive found elsewhere i think G80 is the locker. My Haynes manual says there is a clutch plated operated LSD in some models but doesnt give details, assuming this is the torque biassing diff you mention roger. Does onlyone know which models this can be found on and/or what the axle code is for one?

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