Hopping Brumby

Bushby · Post by **Bushby** » Tue Aug 25, 2009 2:56 am

Greetings to you all,

As this is my first post, I'll tell you a bit about my stock as a rock brumby.
340,000 klms still going strong. Have had it for 12 years no major problems
and never let me down. Not a bad reliability record!!!.
A few issues popping up now,
1. After a warm restart bunny hops when accelerating through the gears, any ideas as to the cause?
2. Transmission oil leaks, including the dreaded front gearbox seal. Replacing seal seems quite straight forward, remove box, remove dual range extension, remove middle housing after using special tool to undo 35mm nut,then split the case and remove input shaft and replace seal and o ring. Any hints on what is involved in successfully assembling this unit?
Any advice would be much welcomed.

Cheers, Bushby

AlpineRaven · Post by **AlpineRaven** » Tue Aug 25, 2009 3:43 am

Bushby wrote:Greetings to you all,

As this is my first post, I'll tell you a bit about my stock as a rock brumby.
340,000 klms still going strong. Have had it for 12 years no major problems
and never let me down. Not a bad reliability record!!!.
A few issues popping up now,
1. After a warm restart bunny hops when accelerating through the gears, any ideas as to the cause?
2. Transmission oil leaks, including the dreaded front gearbox seal. Replacing seal seems quite straight forward, remove box, remove dual range extension, remove middle housing after using special tool to undo 35mm nut,then split the case and remove input shaft and replace seal and o ring. Any hints on what is involved in successfully assembling this unit?
Any advice would be much welcomed.

Cheers, Bushby

Welcome,
First Questions, does it hop while you're changing gears? When was the carby last cleaned?

second question -
Ive pulled gearboxes apart and I know what you're on about, someone else here has done it as well... The only thing you need to remember which they are bitch to deal with is ball bearings that will pop from nowhere if you're not careful, if you're slow and have sharp eyes then you will be okay. Just go slow and watch even read books before starting it to give you the idea. Its not hard task to do so, You might as well replace shaft seals (tail shaft, CV shafts) while you're at that. I dont think you need that 35mm nut? (that socket is for taking the gearset apart?) Just split the gearbox apart by undoing all bolts that is holding the box together.
Cheers
AP

steptoe · Post by **steptoe** » Tue Aug 25, 2009 5:34 am

no points, electronic dizzy? Have you at least done a tune up as in check compression, replace spark plugs, dizy cap and rotor, leads and both fuel filters and air filter?

steptoe · Post by **steptoe** » Tue Aug 25, 2009 5:43 am

and as for gearbox dismantle, I've pulled a 4WD D/R 4 speed apart and never tried to put it back together as those detent balls and eggs and springs came out from everywhere, also did not have that special tool for the big nut so used a jigsaw to make a bigger access hole

. To solve the oil leak I'd make a drip tray and line it with sponge .

Bushby · Post by **Bushby** » Tue Aug 25, 2009 12:27 pm

Greetings,
Many thanks for the swift replies.
A little more info about the ute that I should have supplied in the first place,
1988 model with electronic dizzy, have done all servicing except for the compression test in the last few months. the hopping only happens when the vehicle has been driven for 15 minutes+, then for example I stop at the shops to pick up a few things, maybe ute has sat for 10 minutes or so I get in start up
no probs, drive down the road then it starts to jerk and hop as I accelerate through second and third gears mainly. At all other times it runs perfectly,
so much so I could almost balance a 20 cent coin on it's edge on the air cleaner at idle.
My thoughts were maybe EGR valve or vapor lock as it seems to fun normally again after a minute or so.

As for the Trannie, I have used the drip tray measure for quite a while now,
but the old girl is mainly driven on the highway at 100 kph, leak has worsened to the point where oil now goes over exhaust causing
some fumes to be given off that enter the cabin making it unpleasant to drive. Not to mention the embarrassing smoke haze coming from under the vehicle when I pull up.

Which manual would be recommended to assist with reassembly of the tranny.

Thanks again.

daza · Post by **daza** » Tue Aug 25, 2009 6:21 pm

I wonder if the two faults are related, is the hopping oil on the clutch?
Daza.

Post by **TOONGA** » Tue Aug 25, 2009 7:32 pm

daza wrote:I wonder if the two faults are related, is the hopping oil on the clutch?
Daza.

yeah I would go with that as well a bit of driving to fling oil over the clutch and pressure plate then the shudder would set in

it could also be a faulty fuel pump or blockage in the fuel line

TOONGA

Bushby · Post by **Bushby** » Wed Aug 26, 2009 1:24 am

daza wrote:I wonder if the two faults are related, is the hopping oil on the clutch?
Daza.

Greetings,

This Forum and the People that participate in it are fantastic.I myself would have never considered that the oil leak may be causing the hoppy problem.
Simply brilliant. Will fix the leak and hopefully the hopping will go away.
It may take me a few weeks to do, as like most of us spare time is limited.
Many thanks for your suggestions. Will let you know how it pans out.

Cheers, Bushby.

justincase41 · Post by **justincase41** » Wed Aug 26, 2009 5:16 am

In relation to the 35mm socket, snap on tools manufacture the right socket for this. It is a thin wall socket and costs around $90.00. You could also get a normal socket and have some one turn it down on a lathe as a standard socket is to wide/thick to fit into the access hole to undo the nut so you can seperate the rear section from the split case section. I reakon dazza is on the money with a contaiminated clutch plate from leaking oil. Would be great to see your compression figures for this 340,000km donk.