915: 5th gear shift rod movement when loading and unloading engine

[marlinaness]

I just finished putting together an 82 SC. It was a ground up refurbishment. Last night I drove from Chicago to Newark NJ to ship to Germany. On its maiden trip, I noticed that when I accelerated in 5th gear only, the shifter pulled forward, and when decelerated, it moved back; almost popping out. Transmission is newly rebuilt. The transmission also picked up a little bit of whine (light grating noise) when I accelerated. This was most noticeable in 5th, but also starting being noisier in all other gears. Did I get the linkage set up wrong? Or is there something wrong with the transmission?

I could see the shift rod move during the acceleration and deceleration.

Hopefully it goes on the ship to Germany for summer vacation.

thanks
Marlin

[tobluforu]

Motor mounts?

[john walker's workshop]

maybe shaft end play due to worn tensioning plates and/or worn 4 point ball bearing(s).

[Elombard]

I have often wondered if you could asess the condition of motor or trans mounts based on gear lever movement when acellerating/decellerating.

I guess its probably a combination of things that cause the movement.

[marlinaness]

Hmm,
all the motor mounts are brand new. This occurs only in 5th gear. It wants to jerk out of gear almost. not with other gears. Hence, I thought I might have misadjusted it. Anyway, it's at the port and will be in Germany soon.

Transmission was supposed to have been rebuilt like new. Now I am wondering. I guess I will find out in June.
thanks
Marlin

[uwanna]

Only thing I can think of is perhaps the 5th gear shift fork is maladjusted, not allowing the engagment ring to be "driven home" for full engagement of the dog teeth. That could possibly cause the problem of the trans appearing to try to jump out of gear.
The good news is to check and readjust the shift fork only requires the removal of the front casting "nosecone". The bad news, is you need to drop the motor and trans to do it! Till you fix it, I don't think I would be using 5th gear! Just my $.02.
Good luck!

[marlinaness]

thanks John and uwanna,
I suppose I will have to drop it to find out what is wrong. Happy happy joy joy.

I could feel the shifter moving when I let the clutch out after selecting 5th. Something was definitely loose. Can I surmise it was a bad rebuild since a maladjusted fork or what John suggested was the issue should have been taken care of?

thanks
Marlin

[MBEngineering]

HI Marlin
do you know what torque the pinion nut was tightened to, and was the shafts and gear set's assembled DRY, as it looks like the pinion nut is not correctly torqued up, and with the whine/noise getting nosier I would not drive the car until the box is inspected, the CWP could get damaged, at the first opportunity raise the car and drop the box oil out, then remove the 4 nuts and the selector plate to inspect the pinion shaft, this can then be checked to see if it is loose in the box with a long lever/screwdriver, also inspect the fork on the plate you removed, on each side of the fork ends , to see if the gears have been rubbing against it, this will let you know something is not correct in there.

regards mike

if I can be off any assistance or you need any thing when over this side please let me know

[Autoban]

Marlin, how much is it to ship your car to Germany and back? I'm going to Germany end of July. Would be fun to drive it on the Autobahn for two weeks. Let me know if you need help while over there. I have a friend in Dortmund who may can help you.

[marlinaness]

Mike,
thanks for the detailed insight. I will have it transported to the Munich area from Bremerhaven (costs 350 Euro). I will have a lift available and plan on doing what you describe. I don't have any details on how it was rebuilt, but will start asking those questions.

If I drove it for about 650 miles, do you think it is now ruined. Should I just swap it out with Freisinger Motorsport and pay the penalty?

The cost to ship from Newark to Bremerhaven is $640 when handled by Oceania. A car ship goes out weekly. If interested let me know and I can give you all the info.

thanks all. this is killing me.
Marlin

[marlinaness]

Update.
I got the car to Germany. Transmission moved in and out of 5th only. Opened the transmission. Found the following. The nut was tight, but looks like something was not put together right with the parts falling out below. The picture shows about 4-8 mm of play back and forth with 5th gear and its shaft.
Ideas?
thanks
Marlin

[marlinaness]

ok,
I screwed up those uploads.

hopefully here are the real pictures.

[tobluforu]

Dude, those pics were awesome!

[marlinaness]

thanks
any idea what all the metal parts in the oil are? Any ideas why the 5th gear can move back and forth 4-8 mm?
thanks all
Marlin

[john walker's workshop]

are the bits magnets? was the speedo working? a disc with magnets located under the right side differential bearing makes the speedo sensor generate a pulse. pull off the side cover and lift out the ring gear/carrier assembly to see. does either shaft move in and out? not sure about your 5th gear description. in and out or circular movement? what's that blue stuff, and why do all the busted transmissions have it in there? try kendall 80/90 GL5.

[marlinaness]

John,
thanks again for your time.

speedometer was working up until I took it out of the car. Maybe it was from a previous job. Blue stuff was the gear lube that the rebuilder put in. Unfortunately, I don't know what it is either and the new German rebuilder had not seen this before either. He thought the parts might be from one of the needle bearings, but he didn't have time to open the transmission further and I didn't get to see this until the day before I flew back. He is going to rebuild it for me. RUF estimated the rebuild to be 5000-7000 Euros. Freisinger Motorsport was willing to swap for a full rebuilt for only 3000 Euros.

The fifth gear on the shaft does move in and out longitudanally. The fifth gear can move when moved with the screwdriver a few millimeters so that when I push on the gas, the shift rod moved one way and when I let up on the gas it pulled the shift rod out of gear into neutral. I guess I should have taken better pictures. I am trying to figure out if this was a bad rebuild. It supposedly only had 2k miles. The German rebuilder said it looked like the synchronizer teeth weren't pushed all the way onto the gear. At least that is what I think he said since it was all in German.

I am also going to check with the US rebuilder and see if I can get any insight.
thanks
marlin

best regards

[john walker's workshop]

the blue stuff is swepco. that was just tongue in cheek. some like it, some don't. i think they shift better with kendall. if the picture of the bits was a closeup, we could figure it out better. gotta come apart anyway.

[marlinaness]

aha, now I know what it looks like.

I can't get any more pictures at this time.

In the 1st picture right in the middle, you can see a 4-5mm gap between the synchronizer teeth? and the 5th gear. I was told by the Germany rebuilder that the synchronizer teeth should be pushed up completely next to the gear and this gap was an error? Any thoughts on that?
thanks again
Marlin

[MBEngineering]

HI Marlin
I have a gearbox in the shop now with the same prob' as yours, just looked at 5th and the dog has started to come off, the prob' with the box I have is the input shaft clamp plate bearing has failed, so the input shaft is loose in the box, this has pushed off 5th gear dog and the dog on 3rd, the parts in the bottom of the box could be from the 3rd gear loose gear bearing, as the box I have hear has damaged the thin thrust washer between 2nd fixed gear and 3rd loose gear, with the 3rd loose gear bearing also damaged and starting to come apart,





if you need any thing please let me know.

regards mike

[marlinaness]

interesting. thanks for the picture. I wonder what causes these problems. On mine it looks like the 5th gear and the synchronizer teeth were not pressed together. There was a couple mm gap. The German mechanic said that was a problem, but I don't know if that was the reason for failure. What do you think? He said they are hard to press together. I will be back in Germany in Sep and I hope to find out for sure.
regards
Marlin