Problems with rebuild on 69 Volvo M40 Transmission

[lelshaddai]

So I am working on the reassembly of the Met but am also working on a 62 Volvo 544. I know it is not a Met but I am searching for any help I can get and you guys give good advice. I rebuilt the transmission and I have some problems. It is a M40 4 speed manual. I rebuilt it because 2nd gear was grinding shifting up or down. It had a damaged syncro and spring that hold in the dog slides.

It is a 1969 Volvo 140 drivetrain, OK, I replaced the clutch and rebuilt the gearbox. Replaced damaged syncro, new dog slides and springs, replaced layshaft. Before rebuilding the gearbox I could shift 1st, 3rd and 4th. It would grind going into second either from 1st to 2nd or down from 3rd to second. It had a damaged three gear syncro. Now, after the rebuild I can shift up in all gears, even at hot rod speeds, but cannot downshift from third to second or if in second cannot shift down to 1st. I can shift down when almost stopped. And usually if I push clutch in and give it a little gas and then shift into first. I have little free play and the clutch engages at about 3/4 way up. I have no more adjustment out on the clutch. I had the flywheel resurfaced. It is a Sachs clutch. I do not know now if it is still a gearbox or clutch problem. If I press the clutch in it disengages and revs engine at the 7/8 up pedal. I replaced the pilot bearing when I replaced the clutch. Do I need more adjustment to make up for the flywheel and new clutch? The box easily shifts through all gears when sitting.

I am looking for any advice before I pull the gearbox again. The clutch is at 1/2" free play. The gearbox fluid is even with the hole. 85-90w weight oil. 100f outside. Shifts correctly when not running, up or down. When running will shift up fine 1-4. Shifts down from 4 to 3 but refuses to shift into 2. Not even a grind. I put it up on stands and ran it through the gears. Again would shift up but not down to 2 or 1 until motion is almost stopped. I learned that when it was in 2nd and running and then I shifted into neutral it would not go back into 2nd without motion stopped. Same for 1st. I need help on this. Even if I pull the box I am not sure what to look for. I have a variety of manuals. This is the first time I have tried work on a gearbox. There are a couple of things that stick in my mind. First on the rear long dog slides does the long end go towards the front or the rear(towards the 1st gear or 2nd) The sources I looked at said rear or towards 1st gear. Second:The shifting bars did not look correct. The notches on them would not line completely up with the ball bearing hole. There was not enough room for them to travel all the way to the third notch. One of the shift rods was not straight up with the fork attached. Could I have a bent fork? I would think the shaft is assemble correctly or it would not shift up while moving. No missing or extra pieces. Looked at pictures of my shaft order. Everything went together will no problems.

 

[mike6024]

Have you seen this online rebuild How To? It's got a few warnings in it, like spring orientation. Not sure if they apply but you might look at it.

 

Important change to article here:
Put the second spring wire into place. Orient it so it's a mirror-image of the first one, with the raised part in the same dog as the first.

 

http://www.vclassics.com/archive/tranreb.htm

http://www.vclassics.com/archive/tranhow.htm

http://advrider.com/index.php?threads/volvo-m40-transmission-rebuild.641530/

 

Sounds like you still have some sort of synchro problem not clutch. Sounds like the clutch must be releasing. Or maybe shift rod. Do the detent balls feel like they are working properly when you shift it stationary?

 

[lelshaddai]

Those are the links I used to rebuild the tranny. The gears do feel right when shifting stationary.  I made sure that both springs where mirror image. I agree I do not think it is the clutch anymore. 

[mike6024]

I have had transmissions apart, but certainly not claiming any expertise.

 

Does this trans have interlock pins? Maybe not.

 

http://www.freeasestudyguides.com/shift-rails.html

 

Shift rails connect the shift lever to the shift fork. When the driver moves the shifter to select a gear, the shift rail moves a shift fork that's attached to a synchronizer. Each synchronizer is capable of changing two speed gears. Most five speed manual transmissions have three shift rails.

Shift rails have detent and interlock notches machined into their sides. A spring loaded ball fits into the detent notch to lock the transmission into gear. If the ball slips out of its notch the vehicle will jump out of gear. The rail should slide easily in its bore, but should not have any lateral up and down or side to side movement. While in the desired gear, the interlock pin prevents the transmission from shifting into another gear. For instance, while the first/second gear shift rail is moved, the third/fourth gear rail is held stationary. Check the ball and spring for wear and tension, because a weak spring or worn ball will result in the transmission jumping out of gear.

Shift forks are attached to the shift rail by roll pins. Before attaching the forks to the shift rail, make sure they slide along the rail smoothly. Not binding, smooth, without side play. Check the forks, gates, and the rails for bends, cracks, and excessive wear. Transfer cases also use shift rails with detent ball springs. They’re used to shift between high and low gear ranges. The notch, check ball and spring are used and inspected like the internal linkage of a manual transmission.

 

Bent shifter fork, bent shift rod, something not right with syncro, are some possibilities. Don't know really. If it shifts OK stationary, and also shifts up OK in motion, then I am inclined to think something about syncro in the downshift direction.

[lelshaddai]

No pins in this tranny. It does have the detent notches, balls and springs. It has two forks. 

[mike6024]

The symptoms you describe are as if 2nd gear is not synchronized. So something is not right, probably with your overhauled synchronizer for that gear.