Diff ratios

[Cuppa]

Is anyone able to list the different rear diff ratios that can be matched to a TD42?

I have a mate with a N/A TD42 in a Civilian bus, which he feels is revving too high at 100kph. I believe he has what is known as a 'city diff' at 6.1 to 1. As he is pulling more weight than a Patrol he doesn't want to go to too high gearing, but I'd guess if something like 4.8 or 5 to 1 were available it might suit him. I know 4.1 to 1 is available (theres one on ebay at the moment, but he feels this is likely to be too high.

Cuppa

[MudRunnerTD]

Is he running a GQ diff? Or just after feedback on how it handles that ratio?

Ghee his ratio is huge! Maybe a 4.8 or a 4.6 would be a winner? What is the use of his bus? Passengers or camping? It's geared to carry people. Tell him to turbo it and hell love it

[threedogs]

Cant find my manual atm Will post results first thing in the morning for you.
But thinking 4.8 would be highest

[BigRAWesty]

6.1.... That would be nearly crawling gear ratios in low range..

Kallen Westbrook
Owner of
Westy's Accessories (http://www.nissanpatrol.com.au/forums/showthread.php?15134-Westy-s-Accessories.-A-small-back-yard-builder.)

[Cuppa]

6.1.... That would be nearly crawling gear ratios in low range..



Yes, sounded pretty low to me, but that's what he told me on the phone tonight.

[threedogs]

Never ever heard of any one using 6.1 on any brand.
Most 4x4 I see are fitting larger wheels not smaller

Look at rock hopper and the one from Marks

[BigRAWesty]

Never ever heard of any one using 6.1 on any brand.
Most 4x4 I see are fitting larger wheels not smaller

Look at rock hopper and the one from Marks

6.1 would be for bigger tyres wouldn't it?
I'm confused??? :screwy:

Kallen Westbrook
Owner of
Westy's Accessories (http://www.nissanpatrol.com.au/forums/showthread.php?15134-Westy-s-Accessories.-A-small-back-yard-builder.)

[Rumcajs]

Most GUs with TD42 had 4.3 diffs, only other ratios I've seen are 3.9(TB45), 4.1(ZD30), 4.6 (TD28). On GUs low range is 2.02.
Oh, and higher the number the higher the ratio re:
"I know 4.1 to 1 is available (theres one on ebay at the moment, but he feels this is likely to be too high." so you probably meant "too low"
Cheers

[healy]

Td42 runs 4.1s I thought as an rb30 & zd30 run 4.3s if his after good 4.3s crown and pinion I've got some here from a gq

[Cuppa]

I'm confused now.

If the ratio in his bus (note bus, NOT 4wd- a bus with rear duals, which will be around the 7:50R16 size) is 6.1 to 1 or if it is something else, if his revs are too high at cruising speed, then surely it means the gearing is too LOW doesn't it.

If so he needs a diff which would give him overall higher gearing, but not so high as to let it bog down on hills. The weight it is pulling will be a lot more than a Patrol, perhaps 1 to 2 tonnes more.

I really know stuff all about diffs, & it may be that other diffs than those supplied with TD 42 Patrols might fit/suit??

I'll ask him again for the diff ratio, as well as seeing if he can get a diff model number.

Cuppa

[nissannewby]

It will have a diff ratio due to its box. How many speed is it? By the sounds of it I could nearly gurantee it has a few more gears than the patrol 5 speed.

He either needs to slow down and just coast along at a reasonable speed or if a ratio change is warranted then I wouldnt go under prob 5.6:1 or whatever it works out to be.

[Maxhead]

If he's thinks he's over reving at 100 then he wolud need to come down in ratio ex. 5.? Or similar.
As long as he can still take off in 1st gear easily






.........on the move

[Cuppa]

OK a bit more info.

He confirms it is doing 3200rpm at 100kph
He also says he can take off in 3rd gear.
It has a 5 speed box.
Below is a pic of his compliance plate which seems to indicate it does indeed have a diff of 6.1 to 1.
It is as supplied by the factory as far as we know, with around 80,000kms on it & was used as mine transport in WA. (I wonder if it is possible steep country was involved & the mining company specified this diff? Not possible to find out though, bus was bought at auction in Perth).

Nisshead's comment 'as long as he can take off in first easily' makes sense & fits with what he wants to achieve.

Sooo... working out what might be available & from what vehicle is what is required, hence my original query here in the hope that someone might be able to help.

Cuppa

[taslucas]

Does it have high and low range? Maybe he's in low range. Does it have one if those split diffs maybe?

FanTapstic!

[nissannewby]

Damn lucky I said "nearly gurantee" lol.

I have been having a look around and it seems there is only one ratio available lol. Ill keep looking.

A patrol centre wont fit as its a different centre.

[MudRunnerTD]

The HJ is important. Give Nissan a call and find out what other vehicles have a HJ diff centre and what ratios they run.

Because the bus is designed to carry a greater load than a Patrol it is geared down to accomotate takeoff and acceleration fully loaded. It's been stripped out and converted to a camper ? Then it can have a fairly big change In Ratios and still be a winner.

I would have thought with a cruising rev range at 3500 you could drop down to a 4.8 ratio diff with ease? If you then have trouble pit a turbo on and Happy Days!!

[Maxhead]

Could he compensate by changing the tyre size?

[nissannewby]

Theres a little bit on here.

http://www.nzmotorhome.co.nz/NZMotorhomeForum/viewtopic.php?f=60&t=3982&sid=72cbe93816a08ed2a393fdc7fbafa1d3&start=8

"There are 3 diff ratios in a w40 4.2 civilian bus 6.5-6.143-5.87" Found this on another site. Im not sure if it can apply to the w41 your mate has but may be worth a look.

[taslucas]

Maybe taking off in third is ok on the flat when empty but maybe the gearing is designed incase of a full payload going up a hill

FanTapstic!

[Cuppa]

No it doesn't have a splitter box (like my earlier Civilian with an ED33 motor does).

NN, When you say a Patrol 'centre' won't fit ..... does this mean fitting the internals into the existing housing? What are the possibilities of a complete diff - hub to hub being able to fit - I suppose that might require some major surgery to make it wide enough, if the bus is wider than a Patrol? But..... I saw an H260 diff on ebay, not suggesting it as appropriate for my mate's later bus, but it was advertised as coming out of a Civilian like my earlier one. Haven't I seen the H260 diff mentioned somewhere in regard to Patrols. Might this mean that the width of the bus & of the Patrol might be common?

Apologies if I'm talking a heap of crap, I really know nothing about these things.

I'll wait for a day or two to see if anyone comes up with anything else & then feedback to him what you've all said. Thanks

If changing tyre size, I guess that would mean going to a greater diameter? If so it would have an added advantage of extra ground clearance, but I'm guessing it would need a significant increase in size, probably beyond what is practical?

Appreciate you doing the looking NissanNewby.

Thanks all

Cuppa

[MudRunnerTD]

Assuming the bus is leaf sprung rear then the H260 off the back of a Ute leaf rear may well go straight on! Full diff swap.

[Cuppa]

Assuming the bus is leaf sprung rear then the H260 off the back of a Ute leaf rear may well go straight on! Full diff swap.

It is leaf sprung but having re-read the ebay ad, it seems that if the seller is correct that my mate's bus would need an H290 diff. ..... but from my reading of the ad, it would seem that maybe a 4.8 to 1 diff to fit was made? (HJ48 on compliance plate?) If so, that would sound about right to me???

http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=140935421377&ssPageName=ADME:B:SS:AU:1123

[nissannewby]

No it doesn't have a splitter box (like my earlier Civilian with an ED33 motor does).

NN, When you say a Patrol 'centre' won't fit ..... does this mean fitting the internals into the existing housing? What are the possibilities of a complete diff - hub to hub being able to fit - I suppose that might require some major surgery to make it wide enough, if the bus is wider than a Patrol? But..... I saw an H260 diff on ebay, not suggesting it as appropriate for my mate's later bus, but it was advertised as coming out of a Civilian like my earlier one. Haven't I seen the H260 diff mentioned somewhere in regard to Patrols. Might this mean that the width of the bus & of the Patrol might be common?

Apologies if I'm talking a heap of crap, I really know nothing about these things.

I'll wait for a day or two to see if anyone comes up with anything else & then feedback to him what you've all said. Thanks

If changing tyre size, I guess that would mean going to a greater diameter? If so it would have an added advantage of extra ground clearance, but I'm guessing it would need a significant increase in size, probably beyond what is practical?

Appreciate you doing the looking NissanNewby.

Thanks all

Cuppa

Yeah just changing the diff centre is not an option. I have a ute here with a H260 rear in it and the plate reads HH43.T he more common rears have a HG before them.

It would be a fair amount of work to get a 260 in. Unless as you said it has come from a bus already. Theres the width and then as its been said the need to run duals on it. In that link I posted it says a ford rear end can be bolted in with some slight modifications.

No need to apologise cuppa this is what these things are here for.

An inch of rolling diameter can knock 100 or so rpm off but your up for 4 new tyres then and if a ratio swap is possible will be similar sort of $$

[Maxgq]

Surely it cant be 6:1!? Thats insane?

[Rumcajs]

Td42 runs 4.1s I thought as an rb30 & zd30 run 4.3s if his after good 4.3s crown and pinion I've got some here from a gq

A bit of clarification

[Cuppa]

Thanks Rumcajs, but I think he's going to need an H290 diff, so a Patrol one won't be the go.

Cuppa

[threedogs]

Why not mod a ford 9" ?? M2cW