Tranny Woes
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bradey bunch
- Posts: 189
- Joined: Tue Aug 04, 2009 9:13 pm
Tranny Woes
Hi there! I am the proud new owner of a vw 412 4 speed, and would like some help diagnosing a tranny problem. I have done a fair bit of research on the net and in books, but the only book I could lay my hands on that had anything to do with the 412 was a MOTORS repair manual sitting upstairs at the shop I work at. Anyways, the tranny started popping out of gear last week, very occasionally at first, and now more and more. It only happens in first gear. When this happens, if I press on the clutch and try to put it in gear quickly, it will grind, and then go in, but to avoid this, I have been able to just hold it in gear until I shift. Once in second, It is fine, but occasionally, when I pull it out of second to shift to third, it almost automatically pops out; as soon as I push lightley forwards on the shift knob, there is a popping sound as it goes to neutral, but once again, it has never popped out on its own. I looked under the car while someone shifted and noticed a few things: the motor mounts near the back of the car are fairly soft, but the tranny mounts nearer the front seem OK. Also, the tranny moves a bit when shifting. Lastly, I slipped off the boot that hides the shift linkage that is near the nose cone of the tranny. Where it couples, there seems to be a fair amount of slop, but I am not surehow much there should be. Also, it appears that I could adjust the linkage to make it go further into first gear, but I dont know that that would really help (and could possibly make it pop out of second and fourth instead...) so I did nothing. Any ideas of what it could be? Has anyone had this problem? I have pretty much resigned myself into believing that I need a tranny (and if anyone has one for sale near BC, Canada, feel free to let me know: I will be at the gcvws in coquitlam the 14th to the 16th) Thanks in advance!
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raygreenwood
- Posts: 11907
- Joined: Wed Jan 22, 2003 12:01 am
I have a lot of experience with this. I have a lot of posts on this that may help if you do some searching.
(1) The detents that keep the shift rods in the correct postion might be worn. They are removable externally. Get some thin gasket paper first to be ready...but there is a black plate on the pasenger side about 20mm wide with three screws. Clean around it and remove it. There are three springs under it and three detent plungers. Remove them, clean them and check for worn tips.
(2) Gear shifter adjustment is critcial on these cars. It is in the Haynes manual. Befoe you can adjust the shifter all of the bushings and the drive train alignment must be set right. The tranny and engine are fully suspended from the two bushings that are attached to the ears of the transmission where it mates to the engine . Almost no load is to be put on the rear hange bar bushings and no load at all on the tail cone bushing of the transmission. It is a bumper only that keeps the transmission tail centered so movement does not affect the shifter or put torsional load on the case with will destroy the main input shaft.
It is usually the tail cone bushing being bad that pops you out of gear on this transmission. When it is shot....it allows the transmission to move up and down and side to side. There should be no more tha nabout 3-5mm of movement available in any direction on the tail cone of the transmission before the bumper comes up against the sides of that tube shaped socket in the rear suspension crossmember.
At rest...the bushing should be centered and not touching the sides of that socket. This adjustment is acomplished tilt-wise....by the two vertical bolts that are at the ends of the rear hanger bar. If these adjusting bolts cannot correct the adjustment of the rear tail cone bushing in the vertical axis.....then you need to re-combinate the steel shims that are between the upper transmission mounts right above where the engine mates to the tranny. You will notcie that there are two vertical bolts that hold each bushings bracket to the body. Under each bushing are 3-5 shims.
Basically you put the rear outer adjusting bolts in the middle of their adjustment....start with 3-shims under each upper transmission hanger bushing and then try to readjust the rear outer hanger vertical from that point.
Once you get vertical adjusted......the horizontal is done from the rear hanger bar as well. The two horizontal bolts in each end of the rear hanger bar allow about 13mm side to side adjustment....which pivots the drive train package about the upper transmission bushings...and moves the tail cone bushing side to side for centering purpose.
The rear tail cone bushing must be excellent. If you cannot find one....you can repair yours by removing the rubber from teh bushing bracket...and taking an aftermarket urethane VW fox or rabbit front engine mount...drilling through the center...and slipping it onto the bracket for your tranmission. Ther are several other ways to make this part....but start with teh rabbit golf dfront engine mount method and look at it. You will see what I mean.
(3) if the rear hange bar bushings are heavily oiled and soft...they must be replaced or non of this adjustment can be done. Start by first setting all bushings correct. Then check alignment, It is usually off. It can destroy your tranmission.
The only book out there that decribes this adjustment and the gauges needed to cehck it...is the Clymer manual. in reality....you can adjust without the gauges just as easily...if you use and inspection mirror to be sure that the tail cone bushing is centered. Ray
(1) The detents that keep the shift rods in the correct postion might be worn. They are removable externally. Get some thin gasket paper first to be ready...but there is a black plate on the pasenger side about 20mm wide with three screws. Clean around it and remove it. There are three springs under it and three detent plungers. Remove them, clean them and check for worn tips.
(2) Gear shifter adjustment is critcial on these cars. It is in the Haynes manual. Befoe you can adjust the shifter all of the bushings and the drive train alignment must be set right. The tranny and engine are fully suspended from the two bushings that are attached to the ears of the transmission where it mates to the engine . Almost no load is to be put on the rear hange bar bushings and no load at all on the tail cone bushing of the transmission. It is a bumper only that keeps the transmission tail centered so movement does not affect the shifter or put torsional load on the case with will destroy the main input shaft.
It is usually the tail cone bushing being bad that pops you out of gear on this transmission. When it is shot....it allows the transmission to move up and down and side to side. There should be no more tha nabout 3-5mm of movement available in any direction on the tail cone of the transmission before the bumper comes up against the sides of that tube shaped socket in the rear suspension crossmember.
At rest...the bushing should be centered and not touching the sides of that socket. This adjustment is acomplished tilt-wise....by the two vertical bolts that are at the ends of the rear hanger bar. If these adjusting bolts cannot correct the adjustment of the rear tail cone bushing in the vertical axis.....then you need to re-combinate the steel shims that are between the upper transmission mounts right above where the engine mates to the tranny. You will notcie that there are two vertical bolts that hold each bushings bracket to the body. Under each bushing are 3-5 shims.
Basically you put the rear outer adjusting bolts in the middle of their adjustment....start with 3-shims under each upper transmission hanger bushing and then try to readjust the rear outer hanger vertical from that point.
Once you get vertical adjusted......the horizontal is done from the rear hanger bar as well. The two horizontal bolts in each end of the rear hanger bar allow about 13mm side to side adjustment....which pivots the drive train package about the upper transmission bushings...and moves the tail cone bushing side to side for centering purpose.
The rear tail cone bushing must be excellent. If you cannot find one....you can repair yours by removing the rubber from teh bushing bracket...and taking an aftermarket urethane VW fox or rabbit front engine mount...drilling through the center...and slipping it onto the bracket for your tranmission. Ther are several other ways to make this part....but start with teh rabbit golf dfront engine mount method and look at it. You will see what I mean.
(3) if the rear hange bar bushings are heavily oiled and soft...they must be replaced or non of this adjustment can be done. Start by first setting all bushings correct. Then check alignment, It is usually off. It can destroy your tranmission.
The only book out there that decribes this adjustment and the gauges needed to cehck it...is the Clymer manual. in reality....you can adjust without the gauges just as easily...if you use and inspection mirror to be sure that the tail cone bushing is centered. Ray