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Post by mudgrip4 on Jul 21, 2007 11:24:18 GMT 11
Looking for new truck to build up as project and note a few 2.8 autos about. Could consider one if the price was right - club member has one and it seems fine. Don't know anything about this box however.
The old manual MUA5 is a pretty durable unit. What is the 2.8 auto like? What is code for it? Weaknesses, things to look for? Is it the type in which you can tighten bands - easy to service? Economy of 2.8 with this auto? 3speed plus O/D or just 3 speed?
Appreciate advice
Mike
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Post by geeves on Jul 21, 2007 14:57:25 GMT 11
same auto as the Mus in both 3.1 and 2.8. Also the same box as just about every car out there. A good auto. It uses clutches not bands so apart from oil and filter changes theres no home maintenance to worry about.
ecconomy is virtualy no different to the manual but power will suffer on the 2.8 as the 2.8 dosnt have realy low torque. This is only a problem getting off the line but ok once moveing
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Post by muvit madness on Jul 21, 2007 21:15:15 GMT 11
hi mudgrip alan has a good point as i have a 2.8 auto. yes it does struggle a bit off the line but thats also due to the 35s & not changing the 4.55 ratios? but i dont think they're available anyway. also if i'm trying to climb a steep rock step & i'm nose up against it doesnt want to go i.e (cant get the torque down) but a little rocking motion fixes that. in saying that i wouldnt trade my auto for a manual box any day. e.g in a lot of club outings i've witnessed numerous 4bs stalling against rock steps & traversing senarios a like!! worse thing about stalling when your hard into it is the turbo doesnt like it. another point ive also witnessed is the smell of clutches over worked, these are few eg's why i prefer auto over manual. in my opinion the control in hairy situations makes for easier 4wding. the real test for my auto will be when the pootroll diffs go under with the 36s limoed & locked against what mother nature will dish out  on the road once i get on boost it keeps up allright to a 3.1mu you could say over 1/4 mile there wouldnt be much in it from previous experiences maybe 5 car lengths at best but definately suffers on hills. hope my 2c worth didnt stray off topic too much but just wanted to share some of my experiences with my auto with you. cheers muvit  |
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Post by James W on Jul 22, 2007 9:13:23 GMT 11
Heheh, auto vs manual..... I wouldn't trade my manual for an auto box any day..... for the same reason as muvit... loss of control... I know autos are improving but generally all that autos are good for is acceleration, they work well..... deceleration the older ones are terrible. Appalling engine braking and whats with the sudden jerk when you stop?... really annoys me that one. ... but more to the point....follow an auto down porters pass in your manual and you will see the difference in use of brakes. Using engine braking with a manual the descent is sustainable for as long as you need to. Once you use brakes you need to be very careful that your use of them is sustainable for long descents.... (for those no famular with porters pass, it's 2-3km of 2nd and 3rd gear going up) and how do you really know how much your brakes will take until you get brake fade? This is a fundamental principle of driving with air brakes for example... it must be sustainable. In rail situations I have to sustain brakes for 13km at a time without relief.
For even steeper hill descents I think autos are dangerous will the inability to hold.
Mike do you remember a while back the steep climb at the south end of the waipara bridge the auto mu (forget his name) that came down, the box didn't hold and he had to brake... the back end started to come round which would be catastrophic on that hill. To my mind that is the fundamental difference in performance and driving style between and auto and manual on descents. For one (manual) you learn, don't touch the clutch, and if you do it's pretty obvious why you shouldn't... the other, an auto box you need to brake which is akin to depressing the clutch. Yes I know this is different with hill descent control etc... but this doesn't apply with the older boxes.
Maybe it is different terrain, but I have seen very few manual box stalls nor hot clutches.... driving style is a factor of course.
But, yes but there are pros and cons either way
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Post by Bruce on Jul 22, 2007 10:07:14 GMT 11
We have both behind 3.1 TD and the auto drives me nuts especially towing the camper trailer. Iam always saying to it "when are you going to change gears you !!!!!!!" It needs a service every 20k I have noticed also. No love my manual, so Annie drives the Wizard.
Cheers Bruce.
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Post by geeves on Jul 22, 2007 11:46:52 GMT 11
There are techniques you can learn that overcome the poor downhill control but they do make hard work for the brakes. Ive followed many a 4wd down long hills with rivers at the bottom. All the auto disapear in a cloud of steam from the brakes. The favored technique is often refered to as left foot braking and its far better to be shown it than have it described as the cost of getting it wrong can be quite high
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Post by mudgrip4 on Jul 22, 2007 13:50:28 GMT 11
Appreciate the comments guys. Manual 9 Auto 3... with second half to begin shortly! I think neanderthal and his sons had a few good debates on this subject also...
I confess I am a manual box fan - in part because of the greater downhill engine braking and control James mentions - and this can be hugely important. And I really like the greater choice and precision with the 5 speed manual in all the varieties of off road conditions. Having said that we have all seen plenty of autos perform well in many offroad settings. I think an auto box is something you would come to live with and find good in most situations, but I can't personally go past the fact that the manual is that bit better - no real weaknesses . For this reason after a bit of thought I don't believe I will go for an auto - though the isuzu box seems a good one.
Did catch up with a clubmate with a 2.8 auto and he likes it. Says its bit slower off the mark, but if you hold foot on brakes a bit while building revs, then let go brake it will take off well - even wheelspin. mmm.. this may not be an exceptionally clever idea over time.
Main problem he pinpointed - and its a big one - occurs when you move to bigger tyres (he runs 32s). In doing this you lower the revs in O/D (it's a 3 speed plus O/D box) to just 2100 at 100ks, and the O/D will not now engage at all until about 100kph - a problem Bruce notes above. So you lose a good part of the driving advantage of your O/D, effectively your fourth gear, and v important for fuel economy. Certainly would not help with climbing hills etc either, when you need a range of lower gear ratios at hand.
It appears the 2.8 auto is good box, and people do rightly report some good experience off road, but I think I will stick with a manual - more advantages and no real downsides that I've encountered. And no serious gearing issues with moving up to 33" tyres on a manual, which is what I plan, unlike the auto which virtually loses a gear at this point on road.This would have to affect it offroad as well.
Mike.
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Post by geeves on Jul 22, 2007 19:56:21 GMT 11
1 things also to consider.
You have stated you want a bighorn with the 2.8. These are rare in auto. The owners manual even goes as far as saying they dont exist. Those that do are nearly all Lotus edition ones with the Lotus extras.
As to manual verses auto. The auto can do something that is nearly impossible for a manual. That is change gear in soft sand of during that horrible narly hill climb when you realise you selected the wrong gear. The manual however wont overheat in the same sand.
Im a manual fan as well but wouldnt turn down a auto if the rest of the car was good
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on the road once i get on boost it keeps up allright to a 3.1mu you could say over 1/4 mile there wouldnt be much in it from previous experiences maybe 5 car lengths at best but definately suffers on hills. hope my 2c worth didnt stray off topic too much but just wanted to share some of my experiences with my auto with you.
