Marks 4WD adaptors - Speedo Correction modules

[Olazz]

Guys,

I've had the diffs re-geared and as a consequence the speedo now over-reads. I'd obviously like to correct this and have found THIS.

It claims to be a plug and play for all 91- 97 LC80's via connection to the VSS on the transfer case.
Has anyone used one of these?

Now I know quite of few of you have re-geared your own trucks, so what have you done for this correction? Is there a better or cheaper alternative that works?

Anyone???

Lazz

 

[Chris]

I bought the Mark's 4WD box from Oz. All sorted on the move. Means I can correct for different sized tyres and so on.

It is plug and ply but you have to drill a hole in the tunnel, but they do include the grommet in the pack.

There are cheaper options but they involve cutting plugs off and soldering joints etc. This is child's play.

I re geared, changed tyre sizes AND ended up with a petrol transfer box which means the speedo was a thousand mile per hour out due to the different drive ring. Not a problem with the box.

 

[clivehorridge]

Reading this ad, after coding in your changes to the vehicle (tyre sizes and the like) it appears you get a digital read out of your corrected speed, which it recommends you check against a GPS.

So presumably, you end up with the original speedo reading the same (meaning a wrong reading) and a correct reading on the digital display. Am I correct?

If so, what's the point? If you have a GPS running (which you need to cross check the device) then you know your accurate speed anyway, without spending £220.

I could see the benefit if it corrected your speedo, but to have a separate screen, then you're no better off than having a GPS, which most of us have access to on our phones these days, or a separate Garmin or Tom Tom unit, or iPad as I do.

Confused.... (Chris will say it's not difficult to confuse me and often he's correct!)

 

[Chris]

Get in car, start engine, drive along, look at speed on GPS ( I used 2) press buttons on control unit until car speedo reads what you want it to. Stop car, get out, put kettle on.

Job done. No separate screens

My speedo set exactly to the GPS. You can put it a little over if you like to allow margin for speeding, but I prefer mine to be bob on.

 

[Olazz]

Great thanks CJ, just what I wanted to hear. I read the instructions so was aware of the hole in tunnel. Where have you mounted the module in the cab?

Any pics available?

Thanks

 

[clivehorridge]

So this thing is just for setting it up then, and doesn't need to be on display in the truck?



That at makes more sense now, cheers.

 

[Chris]

No, you don't mount it. It takes a minute then you've effectively done with it. I ran the cable under the centre console then just tucked it under the seat at the back of the handbrake. It's a fix and forget option really. The display tells you nothing once it's set. There's no speed read out or anything. It just says press any key for menu. There are options in the menu as set out in the advert, but I just went for .5% increments or whatever it was. Up and down arrows on the unit. Dial in the speed to you dash speedo. It's really not complicated. Just don't try to set it with Cruise Control on. Best if you have a nice long stretch, get it close then fine tune one press at a time. Mine reads bang on right round the dial.

 

[Olazz]

Great I'll order one then. Thanks for the heads up.

 

[Chris]

It's not what you'd call cheap, but for me, pulling the transfer box out, swapping over the speedo drive gear and putting it all back only for it to still be slightly out seemed like more work than the cost of the unit. As it happens, I should be swapping the T box again this weekend for a diesel one so the speedo will be wrong again. No problem, press menu, dial in the correction, job done.

 

[Geert]

When I went from 33' to 35's I intsalled this unit. The later model gearbox (starting from 93 I think) uses the speedo reading to determine when to shift gears. (so they tell on IH8MUD). I didn't regear but only corrected the speedo with the adaptor. I do have a bigger turbo with adjusted injection pump, but it shifts fine now. Also uphill no problems with changing gears all the time or something like that. So I'm not regearing at all