Daihatsu diesel conversion problems

[Tim Jones]

Hi, I`m on the west cost of SA near Elliston.....I`ve been reading AULRO forums for a while to help me out of the mire I get myself in so I thought it was about time to sign up. So.....18 months into a Milner Daihatsu diesel conversion into a series 3 ex army I`m having gearbox trouble. I rebuilt the box (mainshaft, bearings and a new but stored for ages 3/4 synchro) and also put a high ratio transfer case in while I was at it. To my amazement it all worked......for about 4 days. It started jumping out of fourth but only under heavy load (foot flat down) Total devastation It seems to be getting worse (jumping out with any revs) though I`m not driving it much at the mo....I`ve got some new synchro springs coming but I`m suspecting a misaligned conversion plate that ate the transmission in the first place after reading a thread in the holden engines section. The only other thing maybe is that the clutch sat around for a while and has some rust between the plate and the friction material so is not dead true but engages smoothly. Any ideas anyone before I pull it all apart again?

[Blknight.aus]

no you've pretty much nailed it.

the S3 box that only jumps out of 4th has most likely done the input bearing and will be taking out the center support bearing for the output shaft.

if its jumping out of 3/4 then it can be a combo of the syncro gear, selector forks and the bearings.

[Sitec]

Just reading the words Daihatsu gave me the shivers! Before the box started to play up, how did it go? Milners are usually pretty good. I'd be surprised if they had the conversion ring out of line... How easily did the gearbox go onto the engine when you assembled it?

[Tim Jones]

Thanks for the replies.....it jumps out of 4th under load I`ve only done about 40km for fear of destroying it again but the input shaft bearing still sounds quiet with the clutch in out of gear (quieter than the engine anyway). I`ve realigned the selector fork on the shaft (centralised) and grasping at straws put in the transfer box detent plunger with a reverse gear spring (not much change). It was a bit of effort to get it in originally but I thought maybe it was just a tight spiggot bush (far to excited to do anything about it) but in hindsight I`m hearing alarm bells. Also the clutch had a rattle that ended up being the splined centre being loose (that wasn`t before)......Also the old synchro was very worn even with a spline missing and it was getting a bit of a worry driving it anywhere far(!) The plate does seem well made I was impressed when it arrived but then again milner isn`t milner anymore from the point of view of conversion kits.....by the way whats up with daihatsus I`m loving it (or was) 15000ks on vegetable oil! Thanks guys what do you reckon

[Blknight.aus]

you could try shifting the 3/4 selector a little towards 4th, if this fixes it then the selector fork is worn, or something is not setup right in the syncro/shaft alignment.

[Tim Jones]

I tried it and can feel the detent spring engage and then go past a tiny bit so its definately engaging......I`ve got some new synchro springs coming (The replacement synchro was stored for ages (judging by the dust I got it in a heap of other spares) but appeared unused, certainly hardly at all, no wear on the splines, but I would`ve thought they would jump out on the overrun first???'so I`m thinking I`ll offer the bell housing up when its off the gearbox that should give a clue as to whether the alignment is out......
Glamourous, isn`t it.

[Blknight.aus]

yeah, this is one of the reasons I dont like working on gearboxes on conversion series.

have you tried seeing what the 4th gear selector set does when you dont have the selector mounted on its shaft?

[Tim Jones]

Yes I had a go at that thinking maybe a spring had broken or something but as far as I could see it was doing its thing, moving far enough etc. Does the selector shaft detent do most of the holding a gear in or the synchro detents?Though I`ve never had a properly working one in my hand, I wondered if the action was a bit light (hence the new springs)......Its helping me out talking about it anyway...hopefully I won`t lie awake at 3am tonight......!
At least I think I know how a synchro works now......

[Tim Jones]

Update.......I took the gearbox out today and bolted a bit of angle onto the flywheel face and rotated it....sure enough the ring seems to be sitting about 1mm high. I didn`t have time to try the parallel measurement. I also tried levering the flywheel (gently!) up in case the main bearings are worn but I would`ve thought 1mm would be pretty excessive. Any thoughts on whether this could be an issue before I get the file out, or if levering with a foot long tyre lever would be sufficient to see any movement in the crank?

[Bearman]

Tim, it's been a long time since I played with a series box but I can remember a similar problem occuring if you put the 3/4 synchro unit in back to front. I remember it fits in both ways but will jump out of gear but I thought it was on 4th overdrive not under power.