4.10 gears into 240 1031 rear end

Hey everyone,
I've done a bit of searching but cant seem to find what im looking for regarding this question. I have a 77 245 with a B23ET on LH2.4 with a 2.95 first T5 trans. It currently has a 3.31 rear end which was installed before the T5 when I did the LH2.4 swap. The 3.31 rear was installed as it has the tone ring for the speedo which is pretty important here as in Australia they take speed very seriously and there are cameras pretty much everywhere

As you can guess the 3.31 with the 2.95 first is awful and makes for a car that takes forever to get onto the power and just isnt the right combination. Ive been told a 4.10 out of a 940 can fit the 1031 rear. Is it just a case of me getting an entire 940 rear end, taking it to a shop and having them fit it? Will the tone ring work or will i modify it? Also would I be able to get a truetrac or similar that will work? I will be having a shop do it and I lack the tools or knowledge to do it properly.

Thanks fam.

Have you checked the pinion details on Anthony Hyde's site? I know he has extensive tech. details about the 1030 and 1031 versions..... not certain he has the 9 series 1041 R&P dimensions.

Last time I emailed Anthony, he was retired from teaching......and I'll bet he knows if what you are considering will work.

If the 3.31 already had the tone ring, then it was from a later car that suggests is a 1031 rear. At least in the USA, the 1031 was used exclusively once the electronic speedometer was used from 86+.

940 will have the same size ring and pinion as the 1031. It may be designated a 1041 if it has the g80 locker. There's usually a sticker on the axle tube, facing the rear of the car. Sometimes it requires carefully scraping off undercoating.

Yes, the 4.10 from the 940 rear should swap directly into the 240 rear that you have.

The carrier with tone ring in your 240 rear can be used with the 4.10. The Volvo 3.31 carrier is the same as a Dana 30 carrier for use with 3.73+ gear ratios. Volvo rears use a 3.73+ carrier regardless of gear ratio. If you take the two rears to a shop that is familiar with Dana parts, but not necessarily Volvos, they may tell you that the carrier in your 3.31 rear cannot be used with the 4.10 gear set, but that is not the case with Volvo carriers.

Sorry for not replying sooner. Been busy sorting out the wastegate I posted in another thread
So from the information ive seen it looks like I could effectively find a 940 rearend, hand the two rear ends to a shop and they should be able to swap it all in? If I were to get a truetrac at the same time could it be fitted at the same time? I think G80s are quite rare here in Australia because we dont have icy conditions to deal with here.

Also yeah the 3.31 was removed from a 1990 M47 240 and put into the 77 for the speed signal to LH2.4.

My guess is that the 4:10 that you will find with have a 48T tone ring for ABS, you will have to cut out the extra teeth to make it a 12 if your putting it into a car with non-abs.

I just got done installing a trutrac in my car but it was an older one with no tone ring and thanks to a little research I found that I could cut them in and it would work. Seemed a little shady to me because the tone rings sit on top and the cut grooves go in. I was wondering how that it could possibly read right but it does so thats another option you have.

My next question that I answered myself was will the newer style aluminum cover and speed sensor work with the cut teeth , yep it does.

I just put a modded G80 loaded with 4.10's in my 1031 Volvo 240 rearend. You'll have to set backlash and pinion depth, but otherwise it's plug and play. The G80 requires the passenger side axle to be shortened.

You can use one of these

https://www.bneshop.com/products/1030-1031-speed-sensor-strip

Cheers guys for the help. I will keep an eye out for a 940 in the junkyards here. I will most likely take the parts to a rear end shop as I dont have the tools or expertise for setting lash. Ben those strips look the goods. Might grab one later.