Rattling and clanking transmission in a IIA

[tmckeon88]

I have a 1969 IIA 88" that has a rebuilt RN transmission in it which dates from about 1996. It also has a new Roverdrive. I put in a new clutch this summer, and recently I've been experiencing a strange rattle/thud/clank reaction when I go over a bump in the road. It happens while changing gears or to a lesser extend while just driving. It feels like some sort of backlash in the transmission, because I can feel it through the shift lever, but on smooth roads it shifts normally with no noise. No feeling of the clutch slipping. I was on a rutted gravel road this week and it was shuddering so much it worked the low range lever out of place and into neutral- I thought I shaken the transmission apart.

Any thoughts about where to start looking? Motor and tranny mounts are intact. Is it possible the front drive shaft is banging against the frame? (I have freewheel hubs so the front end is not engaged.) I don't know why that would be starting now, but the noise seems to be coming from under the floors/toward the front. If anyone has any simple tests they know of that I might run before getting into something big like pulling the floors and seeing if the bell housing nuts are loose, I'd be grateful -

Tom

[mongoswede]

I would go around and check all the universal joints in your driveshafts.



I have a 1969 IIA 88" that has a rebuilt RN transmission in it which dates from about 1996. It also has a new Roverdrive. I put in a new clutch this summer, and recently I've been experiencing a strange rattle/thud/clank reaction when I go over a bump in the road. It happens while changing gears or to a lesser extend while just driving. It feels like some sort of backlash in the transmission, because I can feel it through the shift lever, but on smooth roads it shifts normally with no noise. No feeling of the clutch slipping. I was on a rutted gravel road this week and it was shuddering so much it worked the low range lever out of place and into neutral- I thought I shaken the transmission apart.

Any thoughts about where to start looking? Motor and tranny mounts are intact. Is it possible the front drive shaft is banging against the frame? (I have freewheel hubs so the front end is not engaged.) I don't know why that would be starting now, but the noise seems to be coming from under the floors/toward the front. If anyone has any simple tests they know of that I might run before getting into something big like pulling the floors and seeing if the bell housing nuts are loose, I'd be grateful -

Tom

[tmckeon88]

I actually just replaced the rear drive shaft a month ago;the front one is may ten years old but gets little use. Good suggestion though. I think I need to check to see if my 4WD is somehow stuck on even though the levers are set out.

Tom

[rejeep]

im getting a simmialr vibration/rattle while coasting in 2nd...

same sensation.. can feel it through the shifter...

It was suggested to me to check torque on the mainshaft nut..

[tmckeon88]

When I installed the Roverdrive I'm pretty sure I torqued that to more than 100 pound-feet so I don't think that could be it - also the overdrive works fine. I'm thinking of checking that all the bellhousing nuts/studs are in place and tight. I checked the 4WD operation today and that was normal in both high and low range. Still a mystery, especially since it shifts and drives perfectly on smooth roads.

[tmckeon88]

By the way, rejeep, depending on where that rattle is sometimes the red lever can rattle because its linkage is loose, where it attaches under the floor. I've tightened that bolt a couple of times. I don't know if that's even close to what you're describing but it's worth checking.

[Tim Smith]

This is a total guess but since the road surface seems to make a difference, I'm wondering if your mounts are perished and the movement is engaging the parking brake ever so slightly. Have you tried engaging the parking brake while underway to see if you can reproduce the effect?

[scott]

i just got rid of a big clunk! while shifting. thought it was u joints. turns out it was u bolts. all eight were loose allowing the axles to roll a bit

[Nium]

When you replaced the clutch did you replace the bush for the primary pinion in the flywheel? I seem to recall someone having stated a worn bush was the cause of their rig jumping out of gear. Just a thought.

[tmckeon88]

I did not, although it does not jump out of gear usually. (I didn't have too much room to work near the flywheel.) The rattle and shuddering feels like something misaligned. Raining today so I can't do much on it, but I'll get under it in the next day or two to see if something is amiss like a tranny or motor mount or the u-bolts.

[ybt502r]

For what it's worth, I had similar issues with my SIII. It was clearly a "thunk" of some sort, usually when shifting but sometimes from throttle changes. I thought I had loose mounts somewhere. Then it started jumping out of gear (usually 2nd). After reading and looking and trying the easy stuff, I took the floor out and overdrive off. The mainshaft nut was loose. With our host's special tool and new mainshaft nut (the old one had been hammered in), the transmission locked back down and hasn't given me an issue since.

For what it's worth (and this was free advise...)