LT95 Overdrive

FWIW IMHO .. most of the pertinant cons came out in the first dozen posts or so, to summate

the pros are obviosuly

lower engine revs at cruising speed
lower fuel consumption at cruising speed providing you dont labour it up too much

and the cons are

weakening of the driveline
additional noise when in OD


you drive an isuzu so noise is more than likely something you wont notice.

the weakening of the driveline is 2 fold running the overdrive increases the risk of the torque impulses (not the overall torque they're 2 different things) letting your gearbox lunch its bearings and the potiential of the same thing killing the OD itself when the OD glags thats it no drive for you.

Im about to PM brian to see if he'll post up some pics (or email them to me) if his input shaft bearing and main gear and you will get to see the classic symptoms of torque impulse loading lunching a gearbox bearing.

Dave,
Your opinion is always valued :D
Danny

Quote:

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Originally Posted by Blknight.aus

FWIW IMHO .. most of the pertinant cons came out in the first dozen posts or so, to summate

the pros are obviosuly

lower engine revs at cruising speed
lower fuel consumption at cruising speed providing you dont labour it up too much

and the cons are

weakening of the driveline
additional noise when in OD


you drive an isuzu so noise is more than likely something you wont notice.

the weakening of the driveline is 2 fold running the overdrive increases the risk of the torque impulses (not the overall torque they're 2 different things) letting your gearbox lunch its bearings and the potiential of the same thing killing the OD itself when the OD glags thats it no drive for you.

Im about to PM brian to see if he'll post up some pics (or email them to me) if his input shaft bearing and main gear and you will get to see the classic symptoms of torque impulse loading lunching a gearbox bearing.

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I agree Dave, All the problems of fitting ANY transmission behind an Isuzu, N/A or turboed, stem from the torque pulses of this herculean powerplant.

Have I mentioned that I love this engine??:p

JC

http://www.aulro.com/afvb/technical-...te-images.html

theres the link to how the damage gets done.

^^^ that must be due from range changine on the fly:D

no mate thats from changing engine speeds on the fly.

its the input gear from the gearbox not the intermediate gear dogs in the tcase..

look closely at the first pic of the first post of the linked thread. you might just be able to make out the bell housing as opposed to the handbrake mount in the periphery of the picture...

:p

:D I thought it was gonna be a link to some blown LT95 Tx gearsets you've posted before, I hadn't looked at the link, My post was obviously a bit premature, should have read the link FIRST, posted later:angel:

Thanks for letting me know what I was looking at though, I was struggling to tell what it was :lol2:

If the Isuzu engine is so hard on gearboxes how come so many are still happlily running around in front of LT95s in the Army and in Stage 1s and early County's. Surely the failures you highlight are just the odd failures that occur with any box.

Garry

nope the 95 is the tough box that generally deals well with the suzi But it still does have it occour. And its not like it happens overnight in the other gearboxes I would guess that about 60-70% of all the gearboxes have the problem have it taken care of when thegearbox cops a rebuild for some other reason like a worn output shaft, failed syncros, a precautionary rebuild after the oils been run contaminated for an extended time or if its been run sans oil.

think of it like this. youve pulled the box out and apart wouldnt you replace the bearings at the same time ?

I'm thinking a heavier flywheel would help mitigate the low rpm torque pulse issue.