JohnnoK Posted March 29 Share Posted March 29 So, before I go off half coked and start yelling at the guy who rebuilt my gearbox, can anyone help me diagnose what may be wrong with it... Since a full bearings and seals rebuild, it has been stiff going 1st-2nd and 3rd to 2nd and I put it down to settling in post rebuild. I'm not sure of the mileage since rebuild because I didn't record it on the invoice, I only wrote it on the flywheel when I did the clutch at the same time, so I'm going to have to pull the box to get that info. Anyhoo, I pull into the parking lot of a local business and shift from 3rd to 2nd and there is a loud bang and the disco does a "jerk" like something went through the teeth of a gear and the it is "normal" again. I park and do my business and go home, about 4.5km. Next morning, I'm back to the shop and this is when things start to get strange...I'm struggling to find gears and some of the shifts are almost like a crash box with bad double de-clutching and others are silky smooth. By the time I'm back at the shop, I'm down to 1st 2nd and 5th gears. I park the Disco and switch off and the box shifts into some gears with the engine off. I do my shopping, go out to park at the loading dock and as I'm reversing the box feels like it's "tightening up" as the car won't coast in reverse, it needs to be under power to move. Fortunately, it's only about 20 meters of reversing, but then as I leave, it feels the same going forward, but only for a few seconds while still in the yard, and returns to smooth coasting after that. The drive home has15 traffic lights/stop street/roundabouts to exercise my shifting skills and I work out that I can get 1st/2nd OK, but 2nd-3rd is a lottery of maybe maybe not and 3rd to 2nd is grinding until I match the revs nicely. As it's flat roads, I elect to take off in 2nd and some 2-3 shifts remain poor and I once made it to 5th, but getting back into 2nd at the lights was a challenge involving slipping the clutch to get the gears turning and then it shifts into gear. BTW, selecting Reverse is also a slip the clutch and grind it in affair. So, now I'm debating yanking the box out today or tomorrow while I wait for the old bloke to contact me. He's dyslexic so communications is always a problem with him, but as per human nature, "now he's avoiding me"....🙄 Ideas, please??? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 29 Share Posted March 29 Not sure about the main box but I would just double-check it's not stuck in difflock as that can give the winding-up feeling, especially if it's all been apart recently the linkages could be out of wack. 1 Quote Link to comment Share on other sites More sharing options...
JohnnoK Posted March 30 Author Share Posted March 30 10 hours ago, FridgeFreezer said: Not sure about the main box but I would just double-check it's not stuck in difflock as that can give the winding-up feeling, especially if it's all been apart recently the linkages could be out of wack. Thank you, I'll do that this morning. I've got to open the hole in the tunnel to disconnect the gubbins and that will be a good time to check. Â Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted March 30 Share Posted March 30 Almost sounds like the clutch has exploded to me. Quote Link to comment Share on other sites More sharing options...
muzaz Posted March 30 Share Posted March 30 I would have a look at gearbox oil first. I would suspect something wrong with the synchros. Quote Link to comment Share on other sites More sharing options...
Snagger Posted March 30 Share Posted March 30 Sounds like difflock engaged to me, but what oil was put in? Â Should be ATF or MTF94, but EP90 is a common mistake. Â That causes a lot of issues. Quote Link to comment Share on other sites More sharing options...
JohnnoK Posted March 31 Author Share Posted March 31 13 hours ago, Snagger said: Sounds like difflock engaged to me, but what oil was put in? Â Should be ATF or MTF94, but EP90 is a common mistake. Â That causes a lot of issues. I didn't get to checking the difflock yesterday, it was 33 degrees outside, so I cuffed over it. Today's slated to be around 24, so I'm going to crack on with it. As an aside, if the difflock is on, how will that suddenly cause the shifts to go to the dogs? I can understand it messing with the transfer case, but why the R380's shifting? Oil is Castrol BOT 402 SAE75W/85 fully synthetic manual trans fluid. It's all I've ever used and the oil recommended by the guy who rebuilt the box for me. Quote Link to comment Share on other sites More sharing options...
Snagger Posted April 1 Share Posted April 1 On 3/31/2024 at 8:24 AM, JohnnoK said: I didn't get to checking the difflock yesterday, it was 33 degrees outside, so I cuffed over it. Today's slated to be around 24, so I'm going to crack on with it. As an aside, if the difflock is on, how will that suddenly cause the shifts to go to the dogs? I can understand it messing with the transfer case, but why the R380's shifting? Oil is Castrol BOT 402 SAE75W/85 fully synthetic manual trans fluid. It's all I've ever used and the oil recommended by the guy who rebuilt the box for me. It doesn’t seem intuitive that transmission windup in the transfer case should cause gear box problems, but it does. Quote Link to comment Share on other sites More sharing options...
JohnnoK Posted April 2 Author Share Posted April 2 On 4/1/2024 at 10:56 AM, Snagger said: It doesn’t seem intuitive that transmission windup in the transfer case should cause gear box problems, but it does. So, the diff is definitely NOT locked, much to my disgust, 'cos now it's time to drop the whole shebang out and go off to open it all up for a shufti inside. Borrox! 1 Quote Link to comment Share on other sites More sharing options...
Phill S Posted April 4 Share Posted April 4 Sounds like the 3rd/4th synchro has failed? I'd be suspecting one of the springs has broken or become dislodged which will allow the pins to fall out. I'd suggest not driving anywhere - you don't want broken teeth... Here's my prime suspect: Quote Link to comment Share on other sites More sharing options...
JohnnoK Posted April 5 Author Share Posted April 5 OK, update... Stripped the box yesterday and the 5th/reverse pair had picked up badly at some point with a nice pair of grooves in the one gear and a few healthy deposits of metal on the other. Fortunately I have the parts from my original box that ran the input bearing to replace those parts. 2nd gear synchros are showing signs of wear after 16000 kms so new ones going in there, this is thanks to a bit of swarf in the hub mechanism that was making sticktion and resulted in the synchro wearing from having to shove the gear to engage. All the bearings and the other synchros look good, so it's getting a good clean and going back together today for the Haynes "assembly is the reverse of disassembly" re-installation mission. 1 Quote Link to comment Share on other sites More sharing options...
Phill S Posted April 5 Share Posted April 5 That doesn't sound too bad, but surprised at wear on the rings already. As I'm sure are you! No wish to try to teach to suck eggs, but make sure the main shaft is thoroughly cleaned out and if not done already it's worth replacing the pump as a matter of routine, or at least checking the insides... Quote Link to comment Share on other sites More sharing options...
JohnnoK Posted April 6 Author Share Posted April 6 It was all very thoroughly cleaned this time around. I watched him assemble it, quite a procedure. I have it home again and will hopefully get a moment to start getting it back in this weekend, certainly on Monday if the weather holds. Right now, it's warnings of high winds and probable rain. Quote Link to comment Share on other sites More sharing options...
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