Topic: Auto or Manual Gearbox??? (Read 1054 times)

old bob · « **on:** February 22, 2006, 12:47:26 »

I am just changing the engine in my bobtail 3.5 V8 manual g/box (4 speed with o/drive). The new, to me!!, engine is a 3.5 EFI. The engine came complete with a 4 speed auto box. I intended to just drop the engine and box in complete and change to auto transmission.
I have never driven an auto off road what are the pros and cons?
In other words should I change to auto or refit the manual. What does everyone think which is best? The bobtail is mainly used off road with the ocassional local trip and does under 1000 miles a year.

beast5680 · « **Reply #1 on:** February 22, 2006, 12:51:15 »

auto,s are good for offroad as you dont lose your momentum in the sticky stuff trying to clutch and change gear or selecting the wrong gear for a hill :)
i could be wrong but if you change back to manual i think the engine is set up different for an auto box or tuned differently :?

paul_humphreys · « **Reply #2 on:** February 22, 2006, 12:56:19 »

You need to move one of the gear box mounts, I seem to remember. I think you might need the props from the auto as well.

I have not done this and but have looked at doing it a few times.

Paul

GADGETP38 · « **Reply #3 on:** February 22, 2006, 13:08:09 »

have an auto disco 300tdi and the auto box on and esp. off road is fantastic. wouldn't go back now. ;-)

Henry Webster · « **Reply #4 on:** February 22, 2006, 13:30:28 »

Have you got the transfer box that goes with the autobox? Otherwise you will need to find one as the four speed manual is one unit with the main box and transfer box.

H

old bob · « **Reply #5 on:** February 22, 2006, 13:46:27 »

I have the engine, autbox, transerbox and hand brake complete as one lump (also gearbox x-member just in case) with all wiring cables etc. I also have the pedal box for the auto but not the propshafts - i just assumed that they would be standard.

smog · « **Reply #6 on:** February 22, 2006, 13:50:19 »

Driven both manual and auto box motors offroad and to be honest i prefer a manual box. I find it easier to control on downhill roads and stretches of lanes that are steep, most people rely to heavily on brakes with an auto.

That all said i want an auto for a hybrid i am building so the bint can drive it, she loved her auto box in the P38 so hates going off the beaten track as it were with a manual box.

When i have converted auto to manual i have never needed to set the engine up any differently, though i run on carbs not EFI (less to go wrong).

Personally i think it's horses for course situation.

P.S. if you decide to go manual i have a mint recon 4 speed box more than happy to swap for a manual. :lol:

Henry Webster · « **Reply #7 on:** February 22, 2006, 13:52:46 »

You'll have to check the propshafts, I am not sure that they will be the same.

H

old bob · « **Reply #8 on:** February 22, 2006, 14:52:50 »

I will do.
My concern was about the downhill engine breaking i was just wondering if it was the same as sticking a manual into low box 1st gear or if it was necessary to use the brakes as well.

LandRoger · « **Reply #9 on:** February 22, 2006, 15:29:31 »

Just about every off road motor in the States is Auto -they dont seem to
have too many problems, there terrain is more Extreme than anything to
be found in the UK, nuff said i reckon,

robbie · « **Reply #10 on:** February 22, 2006, 18:06:01 »

for what its worth, I too was a little unsure if the auto would be OK or not, but I reckon it is great. I have stopped on hills with no traction, engaged difflock and then done a great hill start with no bother whatsoever.

The engine braking going dowhill took a little to get used to (only the second hill mind you, not weeks) as it does take a second or too to kick in, but once it does, it is fine..... DO NOT USE THE BRAKE!!!!!! better to go where you want rather than where it thinks it wants to go ;)

AND..... you have the information now, before you try it out, I didnt!!!! :shock:

isle of man · « **Reply #11 on:** February 22, 2006, 18:51:55 »

you need to fit a underdrive with the auto for the hill descents.

peter henry

SteveG · « **Reply #12 on:** February 22, 2006, 19:11:28 »

Bullshit! :) :)

The only real drawback of an auto is that if you lose your starter motor you are screwed. Apart from that they are excellent off-road.

Engine braking is not as good with an auto so you are going to descend faster than most diesel manuals, but it's not a problem at all.

If you went up to 35-36" tyres and felt it was too tall you could fit 4.11 R&P's in to bring gearing back to stock.

Cheers

Steve

isle of man · « **Reply #13 on:** February 22, 2006, 21:35:17 »

i am a real fan of the benefit's you get from a autobox so much so that i will include this in my next buggy build.....and the underdrive is a must!!!! unless you are only a softroader.....your choice.

peter henry

muddyweb · « **Reply #14 on:** February 22, 2006, 21:36:36 »

Auto, auto, auto all the way.

Underdrive ??!!? What a waste of 1500 quid. (Just my opinion of course :-))

old bob · « **Reply #15 on:** February 22, 2006, 22:00:43 »

Cheers for the comments.
I think I will stick with my original plan and fit the auto box.
I am hoping that the engine, gearbox and transfer box will go in as one lump- with a bit of fiddling about.
I dont think the weekend offroading I do warrants 1500 quid for an underdrive.

laser_jock99 · « **Reply #16 on:** February 22, 2006, 22:41:20 »

Quote from: "old bob"

I am just changing the engine in my bobtail 3.5 V8 manual g/box (4 speed with o/drive). The new, to me!!, engine is a 3.5 EFI. The engine came complete with a 4 speed auto box. I intended to just drop the engine and box in complete and change to auto transmission.

How about this 27 litre V12 unit.....

http://video.google.com/videoplay?docid=-4412275194202806500&q=v12

SteveG · « **Reply #17 on:** February 23, 2006, 10:25:16 »

Quote from: "isle of man"

i am a real fan of the benefit's you get from a autobox so much so that i will include this in my next buggy build.....and the underdrive is a must!!!! unless you are only a softroader.....your choice.

peter henry

Are you serious????????????????? :? :?

I must be a softroader then, along with all the other Winch Challenge, Rain Forest Challenge, Outback Challenge and Ladoga types that run autos and no underdrive.

All of the people I know that have invested in an Ashcroft underdrive use manual boxes and have bought the underdrive to allow them to winch assist without burning out clutches. An underdrive is cheaper and a lot less hassle than an auto conversion.

But if you want to spend 1500 pounds on an underdrive for your auto that's fine by me, just don't state that it's a must.

Steve :)

FITZ4X4 · « **Reply #18 on:** February 24, 2006, 13:55:28 »

I've driven both offroad in RTV's and winch challenges. My preferences is the Auto.
IMHO, 99.9% of the time the Auto is an advantage. OK , You don't get as much engine braking as the manual but this is rarely an issue. I've been down near verticle hills with the box held in 1st Low and careful use of the brake, I've never had any problems. These hills account for a very, very small proportion of most off road driving, in fact most people would never drive them auto or manual!
Try the auto you won't change back to manual.

Cherry Bomb · « **Reply #19 on:** February 24, 2006, 14:28:59 »

Autos ROCK! 8)

The first descent can be a bit of an eye opener, but if you trust it and let the truck just get on with it it's fine.

News:

AuthorTopic: Auto or Manual Gearbox??? (Read 1054 times)