Gearbox/transfer case issue shudder

[davetheshrew]

Hi

I have a lovely bongo (no rust!!!) that I got in october but its developed a serious issue.

When I got it it ran lovely up to 60mph and then it would get to its final drive gear and start to shake and shudder, I put this down to a wheel spigot issue because the previous owners have put on 18" mazda RX8 wheels on it. Since ive had it also when i go from reverse to drive or vice versa i sometimes get a metal on metal 'ping' sound coming from the back, especially on an incline, no idea if related.

The other day the rear wheels slipped on a little bit of gravel and now its shuddering at all speeds, really shakes the van wildly so its parked up.

I removed the front prop because I read it could be the viscous coupling gone bad but issue remains.

Ive noticed the gearbox pan has been off before and was sealed with liquid gasket badly, there is a small leak for sure.



My Questions

can low oil cause big vibration/shudder?
Is there some kind of vibration damper or something that may have fallen off?
does it sound like the viscous coupling is knackered? bearing in mind ive removed the front prop already.
Are the gearboxes known to go on these?

Many thanks

[g8dhe]

If you have removed the front prop shaft then it can't be the viscous coupling as it won't be driving anything.
As to other causes I think you really need to inspect the underside as a minimum, I do believe there is an anti-vibration/resonance device fitted on the rear diff see here https://www.lushprojects.com/bongoparts ... o=.html#23 item 27-680 its a damper.

[davetheshrew]

If you have removed the front prop shaft then it can't be the viscous coupling as it won't be driving anything.
As to other causes I think you really need to inspect the underside as a minimum, I do believe there is an anti-vibration/resonance device fitted on the rear diff see here https://www.lushprojects.com/bongoparts ... o=.html#23 item 27-680 its a damper.

Many thanks! So removing the prop was a good idea then as Ive eliminated the possibility of it being the coupling . One thing I checked earlier was the oil level while the engine was running I saw zero oil on the dipstick so its very low indeed, when not running there is oil in there passed the full line so cant be far off.

Im definitely starting to worry that the lack of oil has really damaged something badly but will see if there is improvement when i put oil in and post back.

Has anyone cracked one of these open? are there any common fails on these boxes? Im not scared of getting my hands dirty, cheers

[g8dhe]

You measure the engine oil level when the engine is off and the oil has returned to the sump, if you attempt to measure it when the engine is running then it will be totally wrong as the oil is circulating around and there isn't a level to be measured.

This is different from the how you measure the gearbox oil level, which has to be measured when the oil is warm and the engine is in neutral after running for a while, taking a measurement can be fiddly as the oil splashes around and getting a consistent reading needs several attempts normally.

[davetheshrew]

You measure the engine oil level when the engine is off and the oil has returned to the sump, if you attempt to measure it when the engine is running then it will be totally wrong as the oil is circulating around and there isn't a level to be measured.

This is different from the how you measure the gearbox oil level, which has to be measured when the oil is warm and the engine is in neutral after running for a while, taking a measurement can be fiddly as the oil splashes around and getting a consistent reading needs several attempts normally.

ah yeah maybe i should have clarified which level i was checking, it was the gearbox mate. So yes it was the gearbox i checked when in neutral and engine flowing water (hot) and there was zero on the dipstick, oil should be here tomorrow. Thanks for sticking with me on this. I checked the diagrams and unless somehow the transfer box is causing a severe imbalance im leaning towards the gearbox. Il drop the pan when the oil comes and do completely fresh oil. If no improvement I will have to crack it open. Is there any reputable places to get singular gearbox parts for these vans or is that a non starter?

I have a second bongo that was destined for scrap that I am picking up in january so if all else fails i have a second gearbox and drivetrain secured but to be real I could quite easilly have that welded up and sorted so my preference would be to fix.

[g8dhe]

Ah yes if its the gearbox and its showing low then that's not good You will need to drain as much oil as possible but a large amount will be stuck in the torque convertor, some claim you can get more out buy disconnecting the cooling pipes to the front radiator section and use compressed air to get even more out. The filter in the sump is a metal one and it can be cleaned out with petrol. This is why the level has to be measured when the oil is being pumped around as it doesn't all settle into the bottom of the sump.

Be aware that there seems to be many minor variations between the gearboxes, there is a tag close to the output shaft offside with the gearbox ID on, these appear to be matched with the ECU driving it but I've never seen any details on the various variations over time.

[davetheshrew]

well....i think i found the problem. When i went over the gravel i may have bent the propshaft because with all wheels up and in 1st the prop is deviating a good 1cm, not spinning straight at all! Im guessing I got the van like this but the problem was slight, driving it this last couple of months have just made it worse and is now unusable. Il look into getting the driveshaft swapped out and see if that was it. when off the ground gearbox and diff sounded lovely.

[g8dhe]

Oh that sounds nasty, can't say I have heard of that being reported before! Good luck.

[davetheshrew]

Oh that sounds nasty, can't say I have heard of that being reported before! Good luck.

I went under to take a look and it wasnt bent, the rear u joint has completely sheared and is only held the prop together on one pin!!

I will get it repaired but for now will just buy another prop to get me back on the road

Whoever owned it last took no care and didnt grease the grease nipples either so theres backlash on the sliding joint, not great.

[g8dhe]

Ah, yes that's been reported before or similar problems, hopefully you can get it sorted!

[davetheshrew]

Ah, yes that's been reported before or similar problems, hopefully you can get it sorted!

Ive already bought a reconditioned prop from bongo spares so should be back up and running next week.

The extra cool added bonus of all of this is Im getting a ludicrously cheap 'scrap' bongo this month that i was going to do a gearbox transplant with, now I dont have to so within a few months there will be another bongo on our roads, nice silver 4wd one with a fancy bumper, cant wait to get it and start welding

[davetheshrew]

update: all fixed )) Thankfully BongoSpares had the prop i needed, gearbox is bit leaky but fine and topped up so will do that next but the van rolls so smooth now, all vibrations and shudder gone. The prop joint was completely snapped on one joint, ive no idea how it survived driving on it for 2 months.