Looking for 80 series transmission mechanic

Submitted: Sunday, Aug 07, 2011 at 18:19
ThreadID: 88339 Views:4386 Replies:7 FollowUps:13
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Hi!
I have a 1991 turbo diesel 80 series GXL and I think the synchro is stuffed. It's getting hard to down shift into 1st and I can't down shift into 2nd without stopping. The question is whether to go a reconditioned unit or have mine taken apart and fixed because I had the full-time component replaced with a part-time component a few years ago to accommodate an automatic locker in the front diff.
Does anyone know a good mechanic around Burwood East (Vic) known for their brilliant 80 series transmission work? In fact I'm prepared to travel to get it done right. Is better (stronger?) than new possible?
Cheers.
James
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Reply By: happytravelers - Sunday, Aug 07, 2011 at 19:10

Sunday, Aug 07, 2011 at 19:10
Hi James

Just a thought, but what oil do you have in it? I changed the oil in mine once using a general 75-80 gearbox oil and it would not down shift without crunching. I replaced it with Mobil 424 and it was like I'd fitted a new gear box. It might be worth trying a different oil.

Jon
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Follow Up By: jamohamo - Sunday, Aug 07, 2011 at 20:11

Sunday, Aug 07, 2011 at 20:11
Cheers Jon.
I did replace the oil myself recently because of the problem. I used the standard 90W oil but put additives in it to make it shift better (Nulon Gear additive and then Cost Effective Maintenance's AW10). It didn't help much unfortunately. I might try another oil soon but this is a problem that has gradually been getting worse for years. I've just heard something called VMX oil is the ticket for 80 series Cruisers for gears in general but I've always had the thing serviced by Toyota so nothing dodgey should have been going on like cheap rubbish oil.
Recently changing up to second can also be strange. No noise but it feels like the gears just sort of get thrown together inside the box instead of slipping in with each other. Other times it is quite smooth.
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Follow Up By: get outmore - Monday, Aug 08, 2011 at 19:06

Monday, Aug 08, 2011 at 19:06
could be your problem there - why would you put a 90W oil in it? they take a 75-85

I run the vxm-m and while it improved things you really need to learn to double clutch down to second

if you take it easy - dont drive like fangio and learn to double clutch it should be worth at least another 50 - 100000


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Reply By: Member - Rob S (NSW) - Sunday, Aug 07, 2011 at 20:12

Sunday, Aug 07, 2011 at 20:12
Hi James
Your right synchro are stuffed.common problem.
Can't recommend a good mechanic.
A lot of people just learn to live with it.
try castrol VMX-M GEAR OIL
Or Redline MT-90 full synthetic $25 quart.
What i have read is that the original synchros are too short.
Terrain tammer make longer ones to fix it.for longer.

My synchros aren't the best either, i am using full synthetic oil.
and when changing gear leave the clutch pedal in but just pull the gear lever in to neutral then just take the weight of the lever momentary and pause then pull it or into the next gear and it goes smoothly similar to the old double shuffle.

Also factor in a new clutch rear engine seal if the gear box is to come out.

Rob.


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Follow Up By: Member - Rob S (NSW) - Sunday, Aug 07, 2011 at 20:15

Sunday, Aug 07, 2011 at 20:15
Don't put nulon it that makes the sychros worse.
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and that's when I thought I was wrong!

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Follow Up By: Member - Tony S (WA) - Sunday, Aug 07, 2011 at 20:49

Sunday, Aug 07, 2011 at 20:49
you could go back to the old days -- double declutch through the gears and visa versa you would soon get used to it. He He.
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Follow Up By: jamohamo - Monday, Aug 08, 2011 at 07:16

Monday, Aug 08, 2011 at 07:16
Yeah, did try that. Not too bad on the road except the need to use more fuel to spin up the box between clutchings BUT I'm sure it would terrible when 4x4ing.

The other question is is this something that could have catastrophic failure out the back of Burke or does it just pretty much reach this point and get no worse?
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Follow Up By: Member - Rob S (NSW) - Monday, Aug 08, 2011 at 18:00

Monday, Aug 08, 2011 at 18:00
James the gear box will go on for a long time and you won't get a catastrophic failure.
At the worst scenario they will allways get you home.
Drain the oil and get rid of the nulon asap.
And no need to double de clutch/ double shuffle.
just a quick pause between gears and let the stick go momentarily.
no need to rev the engine. well thats work well with mine.
As for 4wding usually best to select the best gear for job before you head of into the extreme stuff.

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and that's when I thought I was wrong!

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Follow Up By: Member - David Will (VIC) - Monday, Aug 08, 2011 at 19:41

Monday, Aug 08, 2011 at 19:41
Hi Rob S,
Why do you say get rid of nulon asap?
What happens if you leave it in, l thought that it was meant to help?
Thanks,
David
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Follow Up By: Member - Rob S (NSW) - Monday, Aug 08, 2011 at 20:32

Monday, Aug 08, 2011 at 20:32
Hi David

I was only doing a bit of research on the sychro problem last week.
And am only going on the findings of many others on the LCOOL, Landcrusier owners online forum, were saying that the Nulon makes the sychros slip more.
reducing the effect of them.
Some mentioned that after putting in nulon, made the box far worse.

I personally don't have any problem with nulon have used it over the years in diffs etc.but wouldn't recommend it as a quick fix for sychros on an 80 series box.

Rob

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Follow Up By: jamohamo - Tuesday, Aug 09, 2011 at 07:02

Tuesday, Aug 09, 2011 at 07:02
I'll see about changing the oil soon to one of the ones specified here. It will depend on availability I think. Not sure how common these are in the shops. Anyway, I'll post the results for sure.
For the record the Nulon did seem to make it worse.
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Reply By: olcoolone - Monday, Aug 08, 2011 at 08:51

Monday, Aug 08, 2011 at 08:51
What make a 80 series trans so special?

It's still only an everyday gearbox and rebuilding gearboxes isn't rocket science.

Sorry I can't help you as I don't know any one who just specialises in that trans.

So 80 series are special!
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Follow Up By: jamohamo - Monday, Aug 08, 2011 at 09:14

Monday, Aug 08, 2011 at 09:14
Obviously I didn't mean that. I am ideally looking for someone who has experience with that particular transmission that is all. I have no mechanical ability whatsoever so I thought it would be better if I was specific rather than vague. The subject may have best been titled "Looking for transmission mechanic for my 80 series".
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Reply By: 120scruiser (NSW) - Monday, Aug 08, 2011 at 14:10

Monday, Aug 08, 2011 at 14:10
It wouldn't matter if you opted for an exchange unit or had yours rebuilt as they will split the transfer case from the gearbox and then bolt the transfer case back up to the reco box. You will still end up with your part time system.
I would try changing the oil to the already stated Mobil 424 or the Caltex Textran which is the same oil. Makes an unbelievable difference to the shifting. Can also use this oil in front wheel drive gearbox's that are starting to get old. It is in my sisters Toyota Corolla that is still original after 420 000 km. The gearbox is a bit loose but changes with no crunches.
Scott
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Follow Up By: jamohamo - Tuesday, Aug 09, 2011 at 06:59

Tuesday, Aug 09, 2011 at 06:59
Mobile seem to have two types of 424 - "Mobilefluid 424" and "Mobile Agri Fluid 424". Is there a difference/preference?
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Follow Up By: 120scruiser (NSW) - Tuesday, Aug 09, 2011 at 07:49

Tuesday, Aug 09, 2011 at 07:49
Good question. I wasn't aware of the two and not sure of the difference. Most use the Mobilfluid 424. I myself have always used the caltex brand called Textran.
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Reply By: Member - MUZBRY(Vic) - Monday, Aug 08, 2011 at 15:35

Monday, Aug 08, 2011 at 15:35
Gday
Try ..Stewart 97631911..




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Follow Up By: Member - MUZBRY(Vic) - Monday, Aug 08, 2011 at 15:38

Monday, Aug 08, 2011 at 15:38
Gday again
Stewart is in Scoresby

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Reply By: Member - Tour Boy ( Bundy QLD) - Tuesday, Aug 09, 2011 at 08:34

Tuesday, Aug 09, 2011 at 08:34
Hi James,
As you have nulon to get rid of you will need to do another oil change after about 1000km and do it when it is hot to flush out the left over nulon. Nulon is awsome in everything except syncros as it is too slippery stopping the syncros from slowing down to do what they are supposed to.
My 80 has 410,000km on the original box and clutch and will crunch if I try to shift too quickly. Drive it like a truck not a sports car and you will be ok. I only ever use the Castrol VMX, but after 3 quick changes to flush out all the mineral oil then the redline is supposed to give superior results but at the price i'll stick to the castrol as it is available anywhere.
Cheers,
Dave
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Reply By: jamohamo - Thursday, Aug 11, 2011 at 08:54

Thursday, Aug 11, 2011 at 08:54
Oils ain't oils ... or something like that. These top 3 are all API rating GL4.

It's a pitty I couldn't put a table in here and it automatically removes multiple spaces.

Product,Grade,Visc@40C,Visc@100C,ViscIndex,PourPoint
Mobil Mobilfluid 424,80W,55,9.3,145, -42C
Castrol VMX80,75W/80W,59.2,10.5,160,-32C
Caltex Textran THD,?,57.5,9.5,148,-39C
for comparison an auto trans oil ...
Mobil 1 Synthetic ATF,?,34,7.6,199,-54C
and a standard gear oil ...
Mobil XHP 75W-90,75W-90,100,15.5,165, -45C

By the way Mobilfluid 424 and Mobil Agri Fluid 424 have exactly the same specs.

So what does this all mean? The Grade is an easy way of showing the oil's characteristics but each rating covers a certain range so is not particularly useful if you want to know the specifics. Vicosity at 40 degrees and 100 degrees are self explanatory and the Viscosity Index is basically a rating of how much the viscosity of the oil changes between 37.8C and 98.9C with a higher value being more stable. The Pour Point is the lowest temperature the oil will pour.

I suppose Mobilefluid 424 is slightly better of the ones discussed if we want to try a non-standard oil because of its lower viscosity.

Stay tuned for some oil changing shannanigans.
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