Rear axles, and final drives

[braindamage]

I've had a quick search but couldn't find anything definitive.

Is there a list of which final drives came in which cars. With these cars being produced over such a long time period and with so many different versions there seem to be quite a few variances.
I know that later cars had the speed taken from their diff, and in turn there are differences here between the abs and non abs cars (number of teeth/windows in the sensor ring). Manuals and autos will have different final drives and was there any difference between estates and saloons?

My car is a 90 estate manual 2l 4 cylinder.

Does anyone have a list of all the different rear ends and what models they relate to?

[Othen]

Originally Posted by braindamage

I've had a quick search but couldn't find anything definitive.

Is there a list of which final drives came in which cars. With these cars being produced over such a long time period and with so many different versions there seem to be quite a few variances.
I know that later cars had the speed taken from their diff, and in turn there are differences here between the abs and non abs cars (number of teeth/windows in the sensor ring). Manuals and autos will have different final drives and was there any difference between estates and saloons?

My car is a 90 estate manual 2l 4 cylinder.

Does anyone have a list of all the different rear ends and what models they relate to?

Re final drives:



... this is only for the auto boxes, I don't know anything about the manuals.

[braindamage]

So if my counting is correct there are 6 variances in the auto boxes alone, not to mention if there are more for the manual.

So the engine is the thing that defines if a car comes with a different final drive it seems?

Im assuming aw55 and bw55 are different auto boxes?

This is great information, thanks.

Does anyone have the equivalent information for manual boxes?


EDIT: In fact it seems the engine alone doesn't mean it has a different final drive, there must be some spec or year changes in there as well that arent covered?

[Othen]

Originally Posted by braindamage

So if my counting is correct there are 6 variances in the auto boxes alone, not to mention if there are more for the manual.

So the engine is the thing that defines if a car comes with a different final drive it seems?

Im assuming aw55 and bw55 are different auto boxes?

This is great information, thanks.

Does anyone have the equivalent information for manual boxes?


EDIT: In fact it seems the engine alone doesn't mean it has a different final drive, there must be some spec or year changes in there as well that arent covered?

... there are also the AW70 and AW71 4 speeders, but they had the same final drives as te BW35/55 and AW55:



BW55 and AW55 are much the same I think - I've never seen an AW55 box but I believe it is the same but from a different manufacturer.

PS. I'd be surprised if there are other rear axles for the manual cars - but I don't know that for sure.

[loki_the_glt]

According to the Haynes book of near-facts there are two different types of rear axle: 1030 and 1031, the latter apparently fitted to "high-performance" models (who ever thought of a 240 as "high performance"?!).

The ratios are as quoted above by Othen with two additional ones: 4.30:1 presumably for acceleration and 3.15:1 that is presumably a high-geared touring ratio.

I suspect that the two are interchangeable for any given final-drive ratio.

BW is Borg-Warner; AW is Aisin-Warner; the boxes are, allegedly, interchangeable.

[Othen]

Originally Posted by loki_the_glt

According to the Haynes book of near-facts there are two different types of rear axle: 1030 and 1031, the latter apparently fitted to "high-performance" models (who ever thought of a 240 as "high performance"?!).

The ratios are as quoted above by Othen with two additional ones: 4.30:1 presumably for acceleration and 3.15:1 that is presumably a high-geared touring ratio.

I suspect that the two are interchangeable for any given final-drive ratio.

BW is Borg-Warner; AW is Aisin-Warner; the boxes are, allegedly, interchangeable.

That is interesting about there having been a 4.3:1 ratio as well Loki, not for this thread, but another that is running here about EV conversions. This is just a thought experiment at the mo, but I found an electric motor I thought might be suitable for the RB (... very long term, maybe 10 years) it produced about 70 kW (about the same as a B21a) at 9000RPM. This implies there would be a need for a ratio reduction to 72% somewhere in the drive train (and so dispense with any gearbox). Well, the RB has a 3.71: rear axle at the moment, so if that was swapped for a 4.3:1 that would give a reduction to 86% - which might be good enough for government work (so the electric motor with a direct drive would spin at 7750RPM to give the same speed at the RB's theoretical maximum (about 120MPH, but there is no way a wheezy 40 year old B21a would get the RB to that speed - and I'm not sure the rest of the car would be very comfortable there either!).

[braindamage]

The reason i'm asking is my rear axle has some play in it and the diff is 210k plus miles old. So i would like to get a separate axle, fully strip it, de-rust and paint or powder coat it, all new bearings and seals and throw an LSD in it.

Not being able to identify what my current axle's final drive is, or what a replacement axle's final drive is could really mess up the way the car drives, as i really don't want to shorten the ratio.

[Othen]

Originally Posted by braindamage

The reason i'm asking is my rear axle has some play in it and the diff is 210k plus miles old. So i would like to get a separate axle, fully strip it, de-rust and paint or powder coat it, all new bearings and seals and throw an LSD in it.

Not being able to identify what my current axle's final drive is, or what a replacement axle's final drive is could really mess up the way the car drives, as i really don't want to shorten the ratio.

In that case you should have said: you can test it yourself by jacking up one wheel and rotating it whilst counting the turns of the prop shaft (divide by two).

I'm not sure about the converting to LSD bit - but there will be people here who know about that.

[heckflosse]

Originally Posted by braindamage

The reason i'm asking is my rear axle has some play in it and the diff is 210k plus miles old. So i would like to get a separate axle, fully strip it, de-rust and paint or powder coat it, all new bearings and seals and throw an LSD in it.

Not being able to identify what my current axle's final drive is, or what a replacement axle's final drive is could really mess up the way the car drives, as i really don't want to shorten the ratio.

You probably have a 3.9.
There was a sticker on the NS of the axle tube with it on, covered in underseal if you are lucky. Pulling the cover doesnt take long and then you will have the numbers on the crownwheel.
Two types of speedo drive, remember.
Jim

[classicswede]

You can take the diff cover off and the ratio is stammped into the crown wheel