Thread: To overdrive or not?

Originally Posted by LouNat58

Tons of great info there guys, thanks a lot. October looks like being when I will splurge on Roamerdrive, can't wait.

You'll enjoy it. Just a little note, which I don't think will be an issue for a TD5. On the Tdi torque comes in at about 1900rpm, so a slightly extended climb on the freeway at O/D 5th would see the revs drop to the point where a downshift was necessitated. But it's easy as you can leave the OD on and just downshift the gearbox, which is actually better for the gearbox, as 4th is a 1:1 output and the OD transfers power through a planetary gear arrangement, so doesn't experience the stress that the 5th gear componentry would.

If you want to hold OD 5th longer, then I'd recommend a VNT Turbo which would of course need a bigger intercooler.

.....oh it never stops!

VNT turbo hey? Seems I have more research to do :-)

Originally Posted by 67hardtop

You tow anything other than a small empty trailer in 5th gear and you will kill ur g/box. 5th gear is meant as an overdrive so to speak as its not 1 to 1 gearing like 4th is. The strain on the 5th gear componentry will kill it eventually. Its the same with all g/boxes, manual or auto. Lock up clutches in autos can slip too if u tow in overdrive/5th.
Anyway just my 2 cents worth.

Cheers Rod

Sent from my GT-I9507 using AULRO mobile app

Hi Rod,
Is your statement in relation to using the Roverdrive or the D2 t/c?
I am still researching, but just about to jump.

Regards
Lou

Originally Posted by 67hardtop

You tow anything other than a small empty trailer in 5th gear and you will kill ur g/box. ...Its the same with all g/boxes, manual or auto....

Sorry but this is a load of the proverbial.
If the gearbox is strong enough and properly lubricated you can tow all day in 5th or 6th. Landrover boxes included.

I have been towing a 5.5m boat and twin axle box trailer for years behind my LT85 in 5th with no sign of deterioration. Synthetic gear oil and regular changes back to 4th to re-oil 5th as advised by Mal Story (Maxi-Drive).

There are isuzu truck gearboxes where 5th and 6th are both overdrive gears. Do you think everyone drives them around in 4th at 80 km/h when they have a load on?!?!?!

This comment has come up on here before and been well refuted many times, yet it keeps appearing.

The bottom line is, if you run good quality synthetic oil and change down to 4th when the revs drop, then your box will last just as long as an aftermarket overdrive.

If you speak to any REPUTABLE gearbox repairer they will tell you exactly what ive said in my previous post. Smart ppl can tow in overdrive as long as they dont overload their drive train and change down gears to stop unneccesary loading of the drive train, but the average joe blow isnt smart enough and just sticks it in 5th or 6th and goes for it and destroys the box. 4th gear is the strongest gear in a manual box as its 1 to 1 gearing (99.9% of gear boxes anyway) not counting trucks etc. If you have an overdrive fitted as an accessory gearbox then the strain is still taken in it when towing and unless the manufacturer of the o/drive says its ok then i wouldnt do it in case it damages it. But this is only my experience and advice, you can take it in any way you feel fit to or even completely ignore it. Its up to you to research it more and ask the ppl who know gearboxes and recondition them daily. Call 360 gearboxes. They know what they're talking about.

Cheers Rod

Sent from my GT-I9507 using AULRO mobile app

Originally Posted by 67hardtop

If you speak to any REPUTABLE gearbox repairer they will tell you exactly what ive said in my previous post. ...

What a load of twaddle.

I have spoken to reputable gearbox repairers. I also know people who design gearboxes for a living.

Some trucks run in overdrive gears most of the time. Here is a big discussion on the relative merits of overdrive vs direct drive from Eaton.
Direct Drive or Overdrive?

On my O/D the power is transmitted through the O/D even when the O/D is not engaged. Are truck O/Ds constructed the same way, or are they by passed when disengaged ?
.W.