Thread: Front Diff Gearing

If we discount some very early 80" Series 1, all Series Landrovers had 4.7 diffs except V8 and Isuzu Stage 1 Series 3, which had 3.54. This includes civilian and military.

However, since interchangeable diffs were used in Rangerover, Discovery, and Defender, and although these almost all used 3.54, and other ratios have been supplied aftermarket, what is fitted to any specific Series Landrover should always be checked by counting turns or teeth before buying parts!

John

Hello All,

Instead of starting another new thread - I might as well divert this one.

Does anyone have any ideas why the front wheels in four wheel drive will engage in high - but will not engage while in low?

As in red gear stick toward the fire wall and yellow button depressed - front wheels lock in (High).

When stopped move red gear stick towards the seat box - yellow button pops up and the front wheels do NOT lock in (Low)

The front does NOT have free wheeling hubs.

Yes - Series III ex-military.

I have placed large rocks along the bottom of my intermittent creek crossing - where it got suck the last time. The last time it was quite some time between drives and I had forgotten the sequence of sticks and buttons. This time I made sure it was in low and the red gear stick was towards the seat box. The back wheels pushed the front wheel onto the other bank - soon as the front wheels should have assisted traction nothing was turning up front Then I lost traction at the back and just had wheel spin. I opened the door leaned out and not even the slightest movement in the front wheels

I wound up pushing the Land Rover out of the creek rather unceremoniously with my four wheel drive tractor. A vehicle whose four wheel drive actually does what it is meant to.

Once the Land Rover was back on level ground I tried low 4WD again red gear stick towards the seat box - nothing no front wheels turning Then I moved the red gear stick forward - yellow button down and the front wheels engaged

So something is amiss with selecting low four wheel drive!

Any ideas would be greatly appreciated.

Kind Regards
Lionel

Almost certainly the four wheel drive selector shaft is not moving freely - probably because the bit sticking out the front of the extension housing is rusty (it should be covered by a pressed metal cover, but this may be rusty even so.

If this is not the case, it will be either a problem with the interlocking system inside the extension housing, such as the bolt loose or missing or broken on the pivoting link, or a broken spring. That it engages from the yellow knob suggests it is nothing to do with the works of the T/C itself, or the actual selector fork.

My money is on the selector shaft sticking. If cleaning up the bit sticking out does not fix it, the extension housing can be removed with the box in situ, or the T/C can gbe removed leaving the gearbox.

John

What he ^^^^^^^ said cheers Dennis

Hello John & Dinty

Thanks for the detailed reply.

I do not know the proper names for some parts. Are the parts such as the extension housing accessible from the bottom of the gearbox/transfer case or do the tunnel covers between the seat box and the firewall have to come off?

A couple of months ago I removed the tunnel and unscrewed all the gear knobs -and in the case of the yellow gear knob I took off the spring and the shroud the bottom of the spring sits in. That is about all that I disconnected and re-connected under the tunnel covers. Perhaps I accidentally knocked something out of alignment at the time?

What section of the Green Bible would identify the extension housing and related parts that you referred to?

I will be having my second attempt at setting some time aside to drive Batty into the shed and putting it up on axle stands. I had planned to get the brakes operational last year. It never happened. The brakes have not worked since I some time before I bought Batty. The previous owner had put one of the rear brake drums in the tray and the wheel was loosely fitted with the wheel nuts so the car could be winched up onto a car trailer. All the seals of the brake wheel cylinders must have been weeping for years - it looked pretty ugly when I took the wheel off while playing "where does this brake drum go". I had a 50% chance of finding the right one first go!

I will test if the front wheels are really moving in four wheel drive or not - once it has each corner up off the ground.

Kind Regards
Lionel

I don't have a Series 3 manual, but it will be the gearbox/transfer case section. The extension housing is the bit the front drive shaft connects to, and the selector shafts arejust above and inboard of this. You can get a bit of a view of them from underneath, and can remove the dust cover and clean them from underneath - but it is a lot easier if you take the driver's floor panel out, and removing the transmission tunnel will make it a little easier again.

I doubt there is anything you could have knocked that would have this symptom.

when you yank the red lever back the first thing it does is clear the front dog into a free wheel postion so the yellow lever can come back up. with that action done the next thing it does is engage the front dog and the low range.

if thats out of whack and you're getting low range but no front Tcase engagement you might not be getting full selection of low range.

its rare for it to be a major issue but the first check you should do (after you clean up the mechanism and make sure the external bits are free to move correctly is to ensure the low range lever is detenting into position correctly, if thats the case then its usually a stuck connection, missing or loose part inside the tcase. ITs possible to have the linkages set up "just so" which if the lever doesnt move the selctor rod for low range all the way into the detent then the front hub wont engage, that could be as simple as a rock stuck on the front of the case, the rubber boot on the lever binding or when it was a part you went washer, angle bit, nut instead of angle bit, washer, nut.

Every part of any issue that could be causing your problems can be addressed without removing the tcase by simply removing the floor on the drivers side and dropping the front prop shaft. Doing the adjustments in situ is possible but its easier to do it all on the bench if the box/tcase has to come out for another reason.

While I was in there I would be renewing the gaskets and front seal. Bet the rear output seal leaks too so since all the toolings the same size might as well do both.

Originally Posted by Lionelgee

Hello All,

Just wondering if there is any difference in the front differential gearing between the civilian Series 3 109s and the military 109 front differentials? Both sourced from the 1970s not a late model Series 3 from the early 80s.

Kind Regards
Lionel

I remember seeing something in the '70's about 4.3:1 diffs in some military Series Land Rovers instead of the standard 4.7:1. Not sure if it applied to Rover diffs but more likely to some ENV diffs that fitted into Rover housings. The only time I ever recall seeing these was once when looking under a military Land Rover. Both diffs were this type.