5 Speed gear box

[profsr]

Have a lead on a 5 speed gear box in India. First of all were these even available? Secondly is there anything that i can do or look for to make sure it is the right one and it will work with my 69? I don't have any pics at the moment but I will get them eventually. Thanks for your help

[Esteban]

I will not encourage you on that box. The only one that we know is the Marks one done in Australia and dedicated for the Patrol. It's a mod from a Cabstar truck transmission (from Nissan).

The Patrol sold in India, the Jonga, had a different engine made over there. A 5 speed transmission was probably fitted to one of these Jongas.

[Swerve]

Dont do it, I've had one. No real benefit as the Patrol is to weak to push 5th gear, 1st gear to low and annoying. 3 speed is much better. ferdy also agrees now he has one, dont do it

[LAG510]

I have a marks 5 spd that might be for sale. I dont know of condition yet but was going to inspect it, clean it up and offer it up. Not sure what they are worth these days, i know they are no longer made. Sorry if this is too off topic. In Melbourne Australia

[RiverPatrol]

Dont do it, I've had one. No real benefit as the Patrol is to weak to push 5th gear, 1st gear to low and annoying. 3 speed is much better. ferdy also agrees now he has one, dont do it

Which model did Ferdy have the 5 speed in? As I recall, you had it in your ute. Our SWBs are lighter than the ute so they might actually do better pushing 5th gear. I know there are small handful here in the US and I've never heard that complaint before.

[Esteban]

I definitely think the Patrol could use an overdrive ratio in the gearbox. I constantly find myself looking for an additional gear when driving on the highway. The torque of the P engine is really good and will tackle a fifth gear like the 0.78:1 of the Marks with ease.

[Johnny Roadkill]

Personally, I think it's a horses for courses question...lots of flattish or gently undulating roads around my area where you're cruising at 80kph/50mph and 5th is handy, and the short 1st gear is great if you are climbing a snotty, rocky hill offroad. But swapping out the 3 speed would be a lot of work and expense if you're not going to actually use the extra gear at each end.
Also the motor itself would be a deciding factor - if you're running extractors, Holley carb or TBI, upgraded ignition and a compression hike then that would make the overdrive usable more often.

Just my thoughts, and only theory until life opens up enough time to put the theories to the test - Swerve and Ferdy have runs on the board in that respect so I hear what they're saying...

Cheers,
D

[Peter60]

Marks 5 Speed. My experience.

I have been driving my G60 Patrols a fair bit over the recent months – great weather here on Oz. Actually, I started writing this six months ago when it was Summer we are now just coming out of Winter!

I have a 1977 LWB Cab/Chassis with a Marks 5 speed gearbox. I have done about a 2,000 kms (1,250 miles). The vehicle drives rather well.

I also have had experience driving my 1968 MWB (now sold) and my 1975 MWB open top over the last 18 months. I have done about 5,000 kms (3,000 miles) in them (combined). Both had the standard 3 speed box.

I regularly swap between my 1977 LWB and my 1975 MWB.

Most of the driving is on sealed roads, but there is some 4WDing in there as well.

I thought I would relate my experiences on the Marks 5 speed.

I did expect to see some differences between the 5 speed vs the 3 speed in engine revs, noise and fuel usage.


SPEED

First gear of the Marks is rather low, however I do use it around town. It seems to make starting from a dead stop easier. I only go a very short distance before the need to change up. When 4WDing I find the low gear handy in some steep situations. While it really isn’t necessary, it just makes my driving easier.

The 5th gear doesn’t really perform under 60kph (40mph). You need a lower gear. So the 5 speed comes into its own at higher speeds.

The 5th gear doesn’t like those long hills. Again, you need to change down a gear to get to the top – sometime even to 3rd gear!

So the 5 speed comes into its own on long, relative flat roads.

I tend to cruse at 80-90kph (55-60MPH) using the 5 speed but 70-80kph (50-55MPH) for a 3 speed. My cruising speed is really determined by comfort and noise levels. With the 5 speed I travel a little faster.


REVS

What I did was that I did some trial runs in 4th gear which is equivalent to top gear in a standard 3 speed gearbox. I then did the same trial runs is 5th gear.

The following table shows that at 70KPH (50MPH) revs drop by about 500rpm.

Marks 5 table.jpg

Speed was measured via a GPS and my rev counter is fairly basic – it only shows to the nearest 100 RPM.

NOISE

I expected that noise levels using the Marks 5 speed would drop at higher speed due to the lower engine noise, however that wasn’t case.

I had the windows up and vents closed and used an app on my iPhone to record Dbs.

Sitting on 80kph (55mph) I recoded 90dBs for both 4th and 5th gear.

I was surprised by this as the engine noise/ revs were very different.

Thinking about this I have decided the iPhone app really didn’t reflect what was really happening noise wise. I think the 5 speed was quitter maybe by about 5Dbs.


FUEL

I didn’t really expect to see much variation in fuel usage based on previous members experiences. On my G60 Patrol with the standard 3 speed, I get about 20Lts/100Kms (12MPG).

In my G60 Patrol with the Marks 5 speed I get a little better fuel economy 17.2Lts/100Kms (13.5MPG)


IS IT WORTH IT?

Absolutely. For two reasons.

1. Lower engine revs. With the 3 speed I am always looking for another higher gear. The engine sounds like it is over-revving. I just feel more comfortable when the engine isn’t screaming so much.

2. It’s a pleasure changing gears. My Marks 5 speed works rather well. You can move up or down the gears with ease. Whist my 3 speed I can move to a higher gear easily but the syncro must be failing and moving down a gear requires a lot of concentration and effort. If the syncro was working correctly I may have a different viewpoint.

My 1977 LWB came with the Marks 5 speed. If I had to buy a 5-speed gearbox for about $1,000-$1,500 AUD then I would struggle to justify that.

[RiverPatrol]

Very excellent review and comparison!!! This is perfect for those considering the upgrade.

[Esteban]

Marks 5 Speed. My experience.

I have been driving my G60 Patrols a fair bit over the recent months – great weather here on Oz. Actually, I started writing this six months ago when it was Summer we are now just coming out of Winter!...

What an excellent and thorough analysis of both gearboxes! Thanks Peter.