Lifted EA81 gearbox issue.

BBoypebs · Post by **BBoypebs** » Tue Mar 06, 2012 9:02 pm

Hi there all.
Having a few issues with keeping reverse gear together in the standard EA81 gearboxes. So I am running 29" tires. Currently I have destroyed two boxes in the process of getting bogged.
So what have others done to with their lifted EA81 vehicles and gearboxes and how good/ bad are the EA81 auto boxes.
So just need a few ideas.
cheers:D

Green_eyed_liberty · Post by **Green_eyed_liberty** » Wed Mar 07, 2012 6:22 am

29" tires? can you put a pic of your car up please, id like to see them fit.

i have 27" and i give my gearbox hell. hasnt broken on me yet (ive done CV shafts, not the gearbox itself)

Matt · Post by **Matt** » Wed Mar 07, 2012 9:56 am

Sounds like a linkage slop to me, depending on the lift in it?

BBoypebs · Post by **BBoypebs** » Thu Mar 08, 2012 10:34 pm

Took a bit of cutting and shutting to make them fit and a two inch lift blocks.
No slop in the box, I actualy sheared the teeth off the gear it self. So not a good situation.

YouTube · Post by **El_Freddo** » Sun Mar 11, 2012 12:11 pm

Have you thought about the 5spd PT4wd L series box conversion? Dunno if they're stronger but I'd say they're more available if you need a replacement.

Other than that you could do a cut and shut on the pinion shaft to run a lower diff ratio, but I'm unsure if this would fit in the 4 speed gearbox.

Cheers

Bennie

BBoypebs · Post by **BBoypebs** » Thu Mar 15, 2012 9:35 pm

Thought of a Five speed conversion but wouldn't never use top gear.
The five and four speed pinion sharfts are not interchangable.
What I do have in mind is get a wider reverse gear made up.

YouTube · Post by **El_Freddo** » Thu Mar 15, 2012 9:43 pm

BBoypebs wrote:The five and four speed pinion sharfts are not interchangable.

I'm not talking about interchanging gearsets, I'm talking about dropping the L series gearbox into the brumby

Cheers

Bennie

Matt · Post by **Matt** » Thu Mar 15, 2012 11:31 pm

As above and have the step down on the flywheel machined from 25mm off memory to 23mm (also ring gear moved back) and you can use a standard l series clutch.

You will need to space the starter backwards with 2 thick washers but.

Matt · Post by **Matt** » Thu Mar 15, 2012 11:34 pm

Also 5th gear in the 5 speed and 4th in the 4 speed is not much difference in ratio, it is only a few hundred rpm.

BaronVonChickenPants · Post by **BaronVonChickenPants** » Fri Mar 16, 2012 4:39 pm

You don't actually gain a higher gear with the L Series conversion, the L Series 5th = Brumby 4th, what you do gain is a gear between your current 3rd and 4th ratios which makes driving a larger tyres bit more manageable.

Jordan.

2nd Hand Yank · Post by **2nd Hand Yank** » Fri Mar 16, 2012 4:50 pm

Matt wrote:Also 5th gear in the 5 speed and 4th in the 4 speed is not much difference in ratio, it is only a few hundred rpm.

Good point.

My L Series 5spd 4wd sounds like it runs passes 3000rpm in 5th before I hit 100km/h.
This is on 185/70R-14's (24.2" tall?)
BBoypeds would probably enjoy the 5th gear on flat roads above 100km/h.

I shift into 5th at 70-80km/h on dead-flat roads for "light lugging/cruising."

But if I need moderate engine power (any grade, slow acceleration etc.)
I won't bother with 5th before 85-90 km/h.
Hard acceleration I wait until 100km/h.

RSR 555 · Post by **RSR 555** » Sat Mar 17, 2012 9:14 am

Matt wrote:Sounds like a linkage slop to me, depending on the lift in it?

BBoypebs wrote:Took a bit of cutting and shutting to make them fit and a two inch lift blocks.
No slop in the box, I actualy sheared the teeth off the gear it self. So not a good situation.

I'm thinking the same line as Matt here.. Not so much the 'play' in the selector but more so the length of the selector. Did you extend this enough? I'm thinking that it's not allowing the selector hub to fully slide over the reverse gear. IMO, this would definately cause the failure you're having.

YouTube · Post by **El_Freddo** » Sun Mar 18, 2012 1:14 pm

RSR 555 wrote:I'm thinking that it's not allowing the selector hub to fully slide over the reverse gear. IMO, this would definately cause the failure you're having.

This makes sense to me, it might feel like it's in gear and hold it there, but the reality of it might be that it's not got the full engagement of the teeth, thus busting the reverse gear due to the load being on a smaller area of the teeth.

Cheers

Bennie

92 brumby · Post by **92 brumby** » Sun Mar 18, 2012 1:38 pm

im running 30's on my brumby with l series 3.9 5 spd and 2 inch lift have no probs with it but the old 4 spd 3.7 strruggled quite a bit

BBoypebs · Post by **BBoypebs** » Sun Mar 18, 2012 11:07 pm

Ok the four speed has a simple straight cut gear which slides between two gears. So there is no slector hub or throw distance issues.
And as far as I can tell by diagrams the five speed has the same setup so I might still inherit the same issue. I have a couple of spare 4 speeds sitting around so keen to use these before converting to five speed,
Does anyone know how good/ bad the 3 speed auto is?

RSR 555 · Post by **RSR 555** » Mon Mar 19, 2012 12:48 am

BBoypebs wrote: Ok the four speed has a simple straight cut gear which slides between two gears. So there is no slector hub or throw distance issues.
And as far as I can tell by diagrams the five speed has the same setup so I might still inherit the same issue. I have a couple of spare 4 speeds sitting around so keen to use these before converting to five speed,
Does anyone know how good/ bad the 3 speed auto is?

This IS the reverse gear selector hub and if not fully selected it will not engage correctly. From looking at this picture, I can see that this gear is not selecting correctly (teeth wearing on one side only) but this is only my opinion and you're better off taking these bits to a gearbox rebuilder and asking his opinion.

Yes the 5 speed does have the same setup but the gear selector shaft (externally) is setup a lot better than the 4 speed. IMO you won't have the same issue as you can modify the arms a lot better. I can send 5 x 4 speed boxes if you ever need any more. I can tell you that I won't ever be using them again.

The 3 speed auto is a vacuum controlled transmission and work very well behind the 1800 but you're going to loose a lot more power trying to drive those big wheels.

BBoypebs · Post by **BBoypebs** » Mon Mar 19, 2012 6:52 am

RSR 555 wrote:From looking at this picture, I can see that this gear is not selecting correctly (teeth wearing on one side only).

The theeth are more than worn unevenly, They are missing.

I'll see what I can modify to mack it better.