69 Bus, Trans Question

[Stray Catalyst]

I have a bus, which I had loaned long term to a friend. I got it back yesterday, and it is making a noise like I've never heard before... howling like snow tires with chains, raising pitch with wheel speed but not with engine speed. I suspect the trans, which I'll be poking at this evening. She told me she thought the oil in the trans was low.

I work for a VW shop which has several donor buses and at least a few transaxles that have already been removed from their donors. Assuming I want to swap it out for another, is there a specific sort of trans that's stronger than others? I'm not offroading, towing, etc but I'd like the best one I can get from the ones that are available - this bus is about to be my transport for a round trip of 7-10,000 miles, lasting several months. I have swapped a trans on a split bus, I'm confident I can do it on a baywindow.

[Marc]

It might be quicker to tell us what options you have, and then we can tell you what'll have to be changed to work in a `69 (and what differences you'll have in the gear ratios).
Least amount of effort/correct gearing for a stockish Type I engine will be any `68-`71 trans (with the short input shaft and no upper mount "ears" on the bellhousing). Avoid the early ones with six little acorn nuts on each sidecover. `71 takes the late style release bearing/clutch cover but that's a worthwhile upgrade IMO...or you can just swap bellhousings.
If you use one that came with a Type IV motor it'll have (A) the late TOB like a `71, (B) the "ears" which could be sawed off if you had to use that bellhousing, and (C) a longer input shaft. The latter's not hard to change once the bellhousing's off.
Generally speaking, the later boxes are stronger but also may have taller gearing (some are geared too tall for a small engine)...and you start getting into starter differences, too. Gross identification can be made by the number of transverse ribs across the top of the case.
So I'd suggest that you start by looking at the 3-ribs for the easiest swap, but keep an open mind about the later ones since some could work and would be beefier enough to warrant the extra effort. Pics would be nice, but at least provide the stamped-on codeletters.

http://www.ratwell.com/mirror/sandlizrd ... /gears.htm
The RH column shows the final drive ratio in 4th - that's the most critical IMO when trying to push a big box through the air...but a combo that has too tall of a First could be a PITA if you frequently have to launch on steep hills, something to consider if the R&P is taller than 5.375:1.

Oh, and on the present box if the noise seems to be strictly related to road speed with little change when you are on or off the throttle, look to differential carrier bearings (or even wheel bearings - might not be transaxle at all). If there's a marked difference in the pitch/volume depending upon the load, the pinion bearing or the ring & pinion gears themselves are the likely culprits - and you probably don't have much time. CV joints generally don't make a growling sound, usually it's more popping & snapping until they self-destruct.

[Stray Catalyst]

It looks like I have a 71 donor bus, but no suitable transmissions that don't have to be extracted from the vehicle. The trans I currently have is worse than I had feared. The front looks like it got really, really hot - enough to bake the road dirt. Trans oil was a grey slurry of small metal particles.

So this weekend I get to remove the drivetrain from the donor bus and install the trans in my bus.


Thank you for the link! The bus has a 1600dp with upright cooling, that info will keep me from picking a trans that the engine can't handle.

[Stray Catalyst]

Salvaged a used trans from a rusty wreck...

And it appears that it's a bad trans, which I spent 23 hours of my weekend removing from the old vehicle and installing in my bus.

So, anybody in New England have a 69-71 bus trans, or a later model one that comes with an engine? If the latter, I have a great running 1600DP, a couple of junk transmissions, and a small amount of money to trade. I know how to extract it from the vehicle if it's the only way to get one.

[Marc]

...or a later model one that comes with an engine?...

You really don't want to go through what it takes to put a Type IV into a `69. There's no ready-made rear hanger system so you'd need to engineer & fabricate your own, and the engine would need to be converted to a configuration which'll fit into the "Type I" environment.

[Stray Catalyst]

Thank you for the advice - the last thing I need is yet another problem. With that in mind, what years of engine will fit into that engine compartment with minimal pain? My budget is limited and my timetable even more so.

[Marc]

Any `68-`71 Bus engine is a direct fit (the doghouse shroud on the `71 requires a different piece of firewall tin to accommodate the cooler exhaust duct).

Any Type I engine which has the three rear engine hanger bosses in the case can be configured to fit (depending upon the stage of completion the case was when raided from the Bus engine production line they may need drilling/tapping/HeliCoiling). The firewall tin is the only significant difference; `68-`71 Buses' heater boxes are different than the Beetle version, but it's a trivial operation to alter Bug boxes to work in a Bus. You can even run a Bug muffler if you whack the apron (yecch!) or make tailpipes that clear it.

A Type III longblock can also be configured to fit but there are a few extra modifications needed - I'll not bore you with them unless you're ready to do this.

Cases which lack some or all of the 3-point bosses can be grafted in through the use of a "Mickey Mount" which hangs the engine by the four oil pump studs and rear-lower case through-bolt...very sketchy, to be used only in the event of a propulsion emergency IMO.

When the doghouse shroud was introduced for `71, the left-upper eng-to-trans bolt hole received a threaded steel insert so the bolt could be tightened from the trans side. Access to the engine-side nut used on the earlier engines is extremely limited so it's best to install that insert if you use an earlier case with the doghouse setup, but there are a couple of other ways to deal with it.

The longer 38A generator used on Buses and Things requires different sheetmetal and an obsolete/rare pulley, and uses a different regulator than the 30A Bug unit - you can run the 30A generator with the appropriate pieces...if you upgrade to an alternator, it uses the "30A" sheetmetal and pulley too.

[Stray Catalyst]

At this point I have a universal case type 1 upright, 1600DP that's in great shape, has a mustache bar, etc. I have four or five 1972 buses in the yard, all of which have transmissions but no working motors - I'll be taking a look at them to see if any have earlier model trans, as to not have to deal with the taller gear ratio and the ears I'd have to grind off in order for it to fit.

No Mickey Mount for me - I'm planning to drive from New Hampshire to California and back again, I'd rather not finish the trip on foot due to having the engine come apart. If I give up on sleep entirely I might have time to rebuild a motor for this, but the only upright engine I have available to me that's bigger than 1600 is a thinwall 1835 that's half finished - again, not the engine for a long trip.

I'll also see if I can fix the trans I already have - primum non nocere, it's already dead so I can't make it worse. I have lots of the wrong transmissions available to me - is it possible/wise to salvage ring and pinion gears from a 72 trans? I assume the bearings themselves should be new, of course, if they're the problem.

I've placed an ad on thesamba, hoping to swap a rusty 74 super convertible for the trans I need - the car's worth more than the average trans but I'm willing to take a loss to get the trans in time and within budget for the trip.

[Stray Catalyst]

I pulled the engine again to access the clutch, and found the problem!

There's a tube, upon which the throwout bearing rides. The 69 trans didn't have one, or even a place to attach one, and I didn't look at the donor trans as closely as I should have or I'd have noticed the problem...



The part of that tube that's closest to the engine, looks like it got mashed by a clutch. It's mushroomed, I had to file it down in order to remove the throwout bearing. The tube is still kind of deformed, and it may be the best idea for me to replace it - but at least it looks like the trans itself wasn't the problem!

I haven't checked the part numbers to determine if the 69 had a 69 trans, or even if the 70 had a 70 trans. Is that tube something that I need, or just a part that's sometimes there, sometimes not? I haven't examined enough bus transmissions to have anything to compare it to. It looks like it's there to guide the throwout bearing, to ensure that it's centered enough to work properly. But throwout bearings are able to move around a little, by design, and seem to work just fine without it on other transmissions.

[Marc]

Gee, if only someone had mentioned that....oh, wait

...`71 takes the late style release bearing/clutch cover but that's a worthwhile upgrade IMO...or you can just swap bellhousings...

The late style release bearing MUST use the guide tube since it's only loosely clipped to the arms of the cross-shaft, rather than nestled in cradles in them like the pre`70 setup. In addition, there are two styles of clutch cover and you must run the one that goes with the release bearing arrangement in use. The early cover has a thrust ring in the center, necessary to apply even pressure to the release levers/diaphragm since the TOB swings through an arc. The late cover has no ring since the TOB is kept concentric throughout its travel range by the guide tube.

The I.D. of the thrust ring is smaller than the O.D. of the guide tube, so forcing an engine with the early cover into a late bellhousing will produce the results you see.

There are three ways to make the trans & clutch compatible. Best is to stick with the improved late setup, which means installing a late clutch cover...some covers are "universal" in that the thrust ring is detachable, but just because the ring can be removed does not guarantee compatiblity with the late setup - the I.D. of the "naked" levers/diaphragm must be large enough to clear the guide tube.

It's also possible to remove the guide tube and install a `68-`70 cross-shaft, provided that the diameter is the same. Since Bus transaxles feature a removable bellhousing, it's arguably easier to simply swap the whole thing (but requires a gasket and a gear lube refill).

Should you choose to use one of those `72 transaxles (they're geared fine for a 1600) you'll need to swap the input shaft, which requires removal of the bellhousing. You could lop off its ears, or install the `71 bellhousing (with good guide tube) if you update the clutch cover OR install a `68-`70 bellhousing and retain the early clutch.

[Stray Catalyst]

If I'd known that the trans was from a 71, I'd have been able to make better use of your advice. However, this is fairly new to me - as I indicated, I wasn't sure if that trans was a 70, or simply was the trans that I took out of a 70 bus where it had not originally lived. It appears to be a 71, based on that guide tube.

So I have the clutch from the 69, which is in fine shape. I have a new clutch, which (as far as I know) is suited for the 69 as well. If the thrust ring is removable and the ID of the fingers is larger than the OD of the guide tube on either of them, then I can use the replacement guide tube that's being shipped to me now. Otherwise it sounds like my best bet is to swap bellhousings and cross shaft (and $40 more in gear oil, but it won't hurt it to be changed again) and set it up as a 68-70 throwout bearing.

[Marc]

Sounds like you've got a good grasp of your options. The early setup has the liability of the cradles in the arms wearing out and allowing the bearing to jump free (in extreme cases, the ends of the arms can break off)...if you step on the clutch with the bearing out of place and the engine running, major carnage to the cover and bellhousing may ensue...so I encourage you to retain the late setup if you can.

One style of cover has the thrust ring retained by a spiral lockring on the inside - if you have that kind you must remove the cover to access it.

[Stray Catalyst]

I have the guide tube coming via mail, but the bus is back together and drivable already as I left it on the lift overnight and the mechanic I work with fixed it. I did indeed kill the guide tube and clutch by not paying enough attention to the problem when I installed the 69 motor with the 71 trans - but I had a spare clutch, so it wasn't as expensive a problem as I'd feared. Next time I pull out the engine I'll install the guide tube, as I'd prefer the more robust setup they had on the 71 trans.

Hooray, another learning experience. Thank you for the advice on how to solve this.

[Marc]

Come again? Did he switch bellhousings or cross-shafts in order to run the early TOB & cover? In that case all should be well.

Or does it still have the `71 bellhousing and late TOB & cover, but with no guide tube? ...or is the tube just shortened?

Late TOB with no guide tube won't work for long; with a truncated one you should be OK for the short term but I would avoid depressing the clutch any further than necessary (and it's never good practice to stay in gear with the pedal down at stoplights, but it's an especially bad habit if the guide tube is compromised).

[Stray Catalyst]

I don't know - I came back to the shop and it was together. I plan to remove the engine and install that guide tube before I go - he's not prone to make foolish mods to cars, but I'd rather have the bus as reliable and safe as any 45 year old van can be. I had the previous trans on hand, so he may have switched bellhousing and all.

I shift into neutral any time I need to depress the clutch for more than a handful of seconds - no need to push the crankshaft out of the back of the engine for any longer than needed.