DIR Return Create A Forum - Home
---------------------------------------------------------
Old Leafsprung Land Rovers
HTML https://ollr.createaforum.com
---------------------------------------------------------
*****************************************************
DIR Return to: Technical tips & Questions
*****************************************************
#Post#: 83589--------------------------------------------------
Diff - iculty?
DIR By: mud
Date: January 8, 2014, 3:48 pm
---------------------------------------------------------
My ebay special 1969 SWB with a 2.5 NAD is running great but the
speedo doesn't go above 30 whn the GPS says I'm doing over 50. I
don't know too much about her, but I'm thinking she might have
higher ratio diffs? She also needs 1st to pull away and doesn't
like hills. Is there a way of confirming and is there a mod I
can do to the speedo to make it more accurate please. I must be
one of the very few leafer owners who has to think about speed
cameras!
Cheers Mud
#Post#: 83593--------------------------------------------------
Re: Diff - iculty?
DIR By: Arjan
Date: January 8, 2014, 3:55 pm
---------------------------------------------------------
Can be the speedo in the dashboard... there are a few different
ones.
#Post#: 83596--------------------------------------------------
Re: Diff - iculty?
DIR By: RMS
Date: January 8, 2014, 4:05 pm
---------------------------------------------------------
To check the diff ratio, jack up one rear wheel (on level
ground, and chock the opposite front wheel) and release the
handbrake.
Make a mark on the tyre and one on the propshaft; chalk is best
if you've got some as it's easy to see.
Turn the wheel one full revolution while watching the mark on
the prop.
If the prop turns about 9 and a half times you have a standard
4.7 diff. If it turns just over 7 times you've got 3.54.
Hope that helps,
Robin.
#Post#: 83597--------------------------------------------------
Re: Diff - iculty?
DIR By: Sunny Jim
Date: January 8, 2014, 4:06 pm
---------------------------------------------------------
It is possible the nut on the rear output flange is loose, so
the speedo gear is slipping. When this happened to me a few
years ago, I had to put a thick washer under the nut so the
split pin lined up with the grooves!
Definitely worth a check; you may find that the handbrake drum
appears loose, otherwise, remove the rear propshaft from the
output flange, take out the spit pin and try tightening the nut.
It can also be a poor quality speedo cable where the end in the
gearbox is merely flattened over and doesn't grip properly. The
better ones have a square fitting crimped onto each end.
Sunny Jim
#Post#: 83611--------------------------------------------------
Re: Diff - iculty?
DIR By: NiteMare
Date: January 8, 2014, 6:20 pm
---------------------------------------------------------
if you need first gear to pull away i'd say you either have a
very knackered engine or more likely 3.54 diffs, i use 3.54
diffs in my Series' but then i do have the 200tdi, this engine
doesn't mean i can pull away happily in second either unless on
a slight dowhill or still inching along
i'm guessing you have a speedo for a swb fitted with small tyres
and it has 7.50s or equivalent along with 3.54 diffs, this
should account for your speedo error and the need to use first
gear
p.s.
in my 109 my speedo reads 35mph (nearasdammit) when i'm actually
travelling at 50mph (remember the 109 speedo is calibrated for
the bigger 7.50 tyres)
also just changing from 6.00 tyres to 7.50 tyres will alter your
gearing by roughly 10% so 10% of 30mph is another 3mph totalling
33mph then add roughly 30% to account for the 3.54 diffs, say
11mph you then have a grand total of 44mph
throw in a little speedo error or drive slippage and you get
your 50mph when only reading 30mph
#Post#: 83613--------------------------------------------------
Re: Diff - iculty?
DIR By: Roveerman
Date: January 9, 2014, 1:14 am
---------------------------------------------------------
Could be just some thing as simple as the speedo needs an
overhaul, they do break, or maybe the drive cable needs
replacing.
#Post#: 83618--------------------------------------------------
Re: Diff - iculty?
DIR By: Doug_T
Date: January 9, 2014, 2:56 am
---------------------------------------------------------
--- Quote from: mud link ---
>
> She also needs 1st to pull away and doesn't like hills.
>
--- End Quote ---
Aren't you north of Reading? You'll struggle to get much out of
a NAD on many of the hills up that way regardless. Can you get
most of the way up the hill from Whitchurch in 3rd (only
changing down into 2nd at the bend near the top)? If so then
your gearing is probably ok.
*****************************************************
Page 1 of 1