5-speed turning - PeachParts Mercedes-Benz Forum

KenB · #1 02-17-2010, 03:51 AM

I'm kind of worried because I've got a Getrag 5-speed and I removed the seals for replacement (not sure if that's related to the issue at hand, though). Clockwise rotation of the input shaft by hand is kinda difficult because it gets "blocked" by something internal. Then I can finesse it to go again for a bit...and so on, start and stop. It will rotate freely and easily counter-clockwise indefinitely, however. There's also a metallic rattle upon rotation now.

What have I done? What must I do?

t walgamuth · #2 02-17-2010, 06:06 AM

I would take it to someone who knows trannies and have them open it up and look at it.

It does not sound good though. It should rotate freely by hand.

JB3 · #3 02-17-2010, 02:10 PM

did you take it completely apart? or change input/output seals and O-rings?

Do the shift levers move, can you change gears?

Whats the housing #?

KenB · #4 02-17-2010, 02:44 PM

Quote:

Originally Posted by dropnosky

did you take it completely apart? or change input/output seals and O-rings?

Do the shift levers move, can you change gears?

Whats the housing #?

I didn't take it completely apart, just the front and rear seals. They're still off. The shift levers move fine and I can shift with proper effect. It's just that the input shaft doesn't like to move clockwise except when I rock it back and forth a bit in fits and starts. I think that metallic noise sounds like a little drag from the front layshaft bearing? CCW turning is unimpeded and smooth, on the other hand.

I'll have to check the housing number but I'm kinda freaked out because I want to know this thing will rotate smoothly and not explode when I put engine power to it. Hopefully someone on here knows manual trannys well and can explain this.

TIA,
Ken

JB3 · #5 02-17-2010, 05:38 PM

well, depending on the model of the tranny, if you pulled the front cover plate off of the gearbox to change the front seal, the bearing race seats in that plate with shims between it and the plate. The bearing has a sliding tolerance on the case, it might be able to move.

I don't know what model you have, but it could be a simple matter of the race has moved out a little relieving pressure on the input/output shaft. It needs the support of that plate to keep everything at the correct depth. For instance, if the input shaft could move out slightly, the countershaft drive gear could hit the lip of the bore. Its a helix cut gear, so it might make noise one way and be silent the other if its touching.

Heres a pic- again, this would depend on the model # but this is a 717.411. Does this look familiar to your model? If so, I would just put the plate back on and rotate it again to see what happens.

KenB · #6 02-17-2010, 06:32 PM

@Dropnosky: That's what I've got, sir! I considered the ideas you mentioned previously but have not tried to re-seat that race. Let me cross my fingers and give that a shot. Do you have any spec for the proper torque on those cover bolts? I also noticed that 4 are a smidge longer than the others. I assume the 4 longs are the top square, the 3 shorts are the lower bolts? Please correct me if I'm wrong.

Thanks very much for even what you've said so far. I suspect (and hope) your assessment is correct.

Best,
Ken

JB3 · #7 02-18-2010, 12:38 AM

There probably is a torque specification, I was unable to come up with one though. Probably someone on the board has the info stashed somewhere.

Can't go wrong with comfortably tight! I just tighten the bolts down until nice and snug. My bolts were all the same length, and there were only 6 in total. My guess would be in agreement with your idea, 4 longers on top, and 2? shorters on the bottom.

all 6 holes look to be about the same depth, so it probably does not matter. Heres a pic from the other side-

KenB · #8 02-18-2010, 01:12 AM

I checked it out tonight. It's a 717.400. My cover plate has 7 bolts, for what it's worth.

Anyway, I snugged the plate down with the shims in place and gave it a shot. I'd say it definitely had an effect but did not completely do the trick. I got a little frustrated and gave the input shaft a few (light) taps with a plastic hammer and that didn't help either (surprise!)

Might I need more shims? May I tap the races around the edges to try to get them back into the housing a bit more? I feel like this is just something stupid that anyone with any experience/knowledge wouldn't sweat but my ignorance has got me spinning.

Thanks for anything further you can add, Dropnosky or others.

Ken

JB3 · #9 02-18-2010, 09:12 AM

So your front plate is rounded at both ends instead of squared off and it has an additional bolt?

I never took one of those apart, I would guess the length of the bolts and where they go in may be very important in this circumstance. It sounds like this casting is also using a tapered roller bearing and shims as well, so it has some similarities, but I know the external shift lever connection is totally different from the 411, 412, and 410, so there are probably some major differences inside the case. There are no snap rings under that front plate right?

I would say you have nothing to lose by lightly tapping the race a little to see if it moved in IF we are sure its got a tapered roller bearing.
I would also try just bolting the cover down with the shortest bolts alone so you know nothing can be hitting, and cycling the tranny through all gears while turning it.

It could just be an internal alignment problem that might pop back into place once you turn it some.

KenB · #10 02-18-2010, 02:47 PM

With the idea that a picture is worth a thousand words:

My GENTLE attempts to fix this issue seem to have made things worse so far. There is now a significant amont of resistance in turning either direction and I can't seem to get it into 1st gear anymore (though I can still get it into others). The output shaft is smooth as silk.

I've resealed lotsa Getrags before (BMWs) and never had an issue. The fact that my slight touchings on this box have caused fairly big changes give me hope that additional slight touches in the opposite direction will fix things back the way they ought to be. Otherwise, I'm gonna have to haul this thing to a specialist and throw lots of money at them.

Ken

JB3 · #11 02-18-2010, 03:30 PM

That looks like its got standard roller bearings instead of tapered roller bearings, which means the earlier depth hypothesis is unlikely. Its probably got a seat on the back side for that front countershaft bearing, and the input shaft bearing may be held in by snap rings. Here a pic of a MAYBE similar setup, notice the lip on the lower bore. heck, it could have snap rings on the opposite side on the inside of the case!

the 2nd pic shows what I mean about the snap rings. In this pic, the snap ring fits into a groove on the bearing and the shims were to the inside of the snap ring on the exterior of the case. Tapping this setup lightly would really do nothing either way if the snap ring is in place-

Im at a loss at what you could possibly have done, if anything. Maybe its just the difference in feel as the case drained of fluid? What does the output seal look like? Is there any possibility of any cause there?

It looks like this model has elements of a bunch of different MB setups, so in that case, unless someone on here has actually been inside a 400, your best bet at this point is probably to take it by some tranny shop and get their opinion.

KenB · #12 02-18-2010, 03:54 PM

Hmm. My set-up really looks like that 2nd photo you posted. I mean, on the input shaft, I've got a snap ring, then a spacer-type collar, then the kind of gapped "snap ring" (is that what you would call that too?) that can be seen in your photo.

My output seal is currently off as well. Nothing seemed amiss there in pulling it.

Yeah, I don't know what I could have done either. Maybe I will try filling it with fluid, but seems like it shouldn't practically lock up just because of no fluid when hand turning.

Thank you!

KenB · #13 02-18-2010, 06:02 PM

OK, this should help with the diagnosis, I would think:

I put the front cover on and filled it with about a liter and a half of MTL just for kicks. No change, really.

Then, I shifted through the gears a bit, moved things back and forth. That's when it kinda freed up and I'm back to it turning without any resistance CCW. Also back to square 1 on the CW turning--fits and starts but gets blocked.

FINALLY: tilting the tranny forward (tail in the air >30*) the input shaft will spin freely and smoothly and silently in both directions, in all gears (YAY!) It will do this as long as I tilt it. When I level it out a bit, it starts catching on something again.

So, what's this mean? I cannot swear 1000% it wasn't like this when I got it. I would be totally satisfied if I were planning to mount this thing vertically but I don't think that's gonna work for me.

Ken

winmutt · #14 02-18-2010, 07:29 PM

Your gonna need a lift kit for the back of your car. Monster truck?

JB3 · #15 02-18-2010, 07:45 PM

Maybe some foreign object got into that exposed bearing causing it to drag? Did the gasket between the plate and the case come off as one piece, or did it break into little bits and maybe get in there?