Grinding transmission after engine swap 😫

[jeremypbeasley]

Dear internet,

I’ve just completed my first ever engine swap and rebuild of everything outside the heads and block. Put it all back together, set the timing, and it sounds great. Original transmission with no known issues and fresh oil.

Like a cold bucket of water over a hot shower curtain, when I went to shift into gear I realized my work wasn’t done.

When I press the clutch and shift into any gear, the transmission grinds just like I hadn’t pressed the clutch at all. I immediately assumed it was a bad slave cylinder or that the throwout bearing had come loose during install.

I took the transmission off and checked everything. Throwout bearing was clipped on fine. Slave was operating with the pedal as expected.

I put the transmission back on with the shift linkage connected (without the CVs connected and still on jack stands) and cranked it back up. Shifted in and out of gears just fine. Slave and pedal were operating just fine too.

A few minutes later, I attached the CVs, dropped the jack stands, and cranked it back up.

Grinding! Same as before. Anytime I try to put it in gear.

I’m at a loss.

My only current suspicion is that it has something to do with the shift linkage and somehow the shift lever on the transmission is not moving fully into gear. So I had my friend shift it with the engine off while I watched the shift linkage underneath. It appears to be working just fine, with only a little toughness shifting into second gear.

Any clue what could be wrong?

Thank you forever and ever.

[danfromsyr]

what swap did you do?
a VW inline 4cyl?

did you trim the input shaft on the transaxle.
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[?Waldo?]

Have you tried bleeding the clutch?

[crazyvwvanman]

Did you put a new clutch pilot bearing in the end of the crankshaft?

Mark

[jeremypbeasley]

Haven't tried to bleed the lines. Total shadetree over here. Doing that this afternoon.

Replaced/swapped it with an '85, 1.9 4 cylinder just like it had before.

I've replaced a pilot bearing before but I didn't have one handy when I put the new engine on. With the existing pilot bearing new and spinning nice and easy, I just left it. Foolish, I suppose. Would that really prevent any shift?

[Destructo]

You obviously understand the components you're working with but something must not be lining up correctly.

You say it shifted fine in and out of gears without the CVs on. Did you confirm the axle output flanges turned as well and you're sure you tested it with the engine running before the CVs were attached?

If that is correct, you may need to recheck your 4 bellhousing to engine studs after you lower the vehicle back down. That may be pushing things out of alignment especially if the studs aren't fully tightened.
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1985 Wolfsburg Edition Westfalia Camper Bostig conversion

Dude, where's your van?

[jeremypbeasley]

Right on. I’m also gonna try lifting with the axles still on and see if it persists.

Here’s the slave in action. Does this look like the proper range of motion?

http://drp.mk/i/13w484Lt16

[dobryan]

[?Waldo?]

I don't know that I would be able to tell visually between the range of motion of the clutch lever on a properly working one vs. one that does not quite give the proper range of motion for easy shifting.

It makes sense to me that it would shift without the CVs attached but not afterward. Without the CVs attached, the output side can adjust itself as the gears are meshing. I haven't ever tried to shift with the engine running without CVs attached, but imagine it might be doable without even using the clutch. The added inertia of just the driveshafts and wheels even if off the ground might be enough to prevent it from shifting if the clutch is not decoupling the engine and trans.

I would also mention that I did once have a clutch master cylinder fail in the way that is described. The clutch pedal still felt normal and the lever on the trans moved, but did not move far enough to decouple the engine and trans and allow smooth shifting.

If I were in the OPs situation I would bleed the system first to rule out air in the fluid as the culprit and then if it still will not shift and the slave does not leak, then I would replace the master.

[jeremypbeasley]

Thanks Waldo!

My checklist for tonight:

- Bleed any air out of the slave cylinder (simple bottle/tube method)
- Top off brake fluid if needed (Dot4)
- Recheck 4 bellhousing to engine studs and bolts, torque to spec

If nothing else prevails....

- Replace pilot bearing
- Replace master cylinder

[MarkWard]

I would start it in gear with the clutch pedal depressed. If the van starts and idles, that might indicate that the clutch is working. If something other than that happens, the clutch might have a problem.

If you do pull the transmission make sure the clutch disc slides freely on the input shaft. I will use a “film” of grease so the splines are not dry.
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[Sodo]

Agreed on the attempt to spin the engine with trans in (4th) gear. If the starter can turn the engine at all then the clutch is releasing, but not enough.

Is the engine 100% mated to the tranny?
No gap between the engine & bellhousing? Look for a gap near all four engine studs.
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'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb

[DanHoug]

[jberger]

shift lever bracket installed on the correct side of the transaxle boss?

J

[jeremypbeasley]

Back at it.

Back bled the slave line, no air in the lines. Bolts from engine to bell housing were still torqued to spec. Fluid was and still is just above max in the reservoir.

Starts in gear with the wheels off the ground just fine.

I have no reason to believe that the slave or master are malfunctioning.

My only conclusion is that my pressure plate or clutch disc are damaged from only five miles of driving on my old engine that I ditched for what was ultimately excessive end play on the flywheel. Eternally bummed.

Guess the transmission is coming off again. Any other bright ideas?

[?Waldo?]

Why do you assume it is the clutch/pressure plate as opposed to the clutch master cylinder? It seems to me that the clutch master is more likely to fail than the pressure plate. I don't see how excessive end play would damage the pressure plate and certainly not in 5 miles. I've had a clutch master fail simply from the vehicle sitting. I've never had a pressure plate do so. As a final point of logic, changing the clutch master cylinder is both less expensive and a whole lot less labor than replacing the pressure plate/clutch disc. I'm not saying it IS the clutch master cylinder, but it makes more sense to me to replace the cheaper and easier to change part than to start with the more expensive and harder to change part. I'd rather change the master and find out it was an issue with the clutch pressure plate/disc then find out it was the master cylinder after putting in the labor and expense of changing the pressure plate and disc.

[MarkWard]

The test I described was with the wheels on the ground not in the air. Did you install the clutch disc backwards?
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[jeremypbeasley]

Fair points. I suppose my logic is that I assume anything I touched (clutch kit) is more likely to be the source of the problem than something I didn’t (master cylinder).

I’ll see if I can find someone with the part locally and give it a shot.

[?Waldo?]

[jberger]