TheSamba.com :: View topic

Tue Mar 19, 2019 3:29 pm

Okay folks I have an issue with my wife/daughter's '73 Automatic Transporter. I have suspected an issue for a few weeks now but was somewhat afraid to look for fear of what I might find. Kind of like being scared to go to the doctors for fear of a diagnosis. And yes, I know both are stupid. I am constantly reminded of this by my wife. We put the bus in the garage until we can figure this out.

Some background- I have a '67 Westy that takes up most of my wrenching time and I feel totally comfortable in doing almost any thing with this bus to include tackling major engine issues. Type-1s are so easy. The Type IV engine on my wife's Bay seems far more complicated (too much going on in there), and it having an auto trans makes it down right intimidating. I do the brake work, electrical, etc. and have sorted out most of the PO's electrical hack job.

We have had this bus for close to 10 years now and it has run well. No issues with power or shifting. About two weeks ago we noticed a strong burning / hot smell after the bus has been driven for several miles. I checked the engine temp with a meat thermometer in the dipstick tube and a laser thermometer on the block. Both read about 218 - 220* which seems about right during a drive @ 55MPH. It does not smell like a hot engine, rather a different smell I am unfamiliar with. No brake issues like rear brake pads rubbing. No fires thank goodness. ATF was low so we refilled it. Smell still there.

After reading several threads concerning auto trans I suspected this may be the issue so I thought I would drain the old ATF and clean the screen, replace the final drive trans fluid. I do believe the ATF has gone into the final drive and explained the low ATF. I purchased a new ATF pan seal.

Issues:

1. I assume you drain the ATF via the bottom of the oil filler tube by removing it. It's on very tight, can not be removed and may be thread locked. Is it reverse threaded? I am afraid of F'n it up.

2. The ATF pan has been sealed with a blue gasket glue and won't budge unless prying it off, but this won't do any good until I can remove the filler tube.

3. Can't find a drain plug on the final drive. Filler plug but no drain plug. Is it under the final drive pan? Do you just drain via the pan?

4. Is the smell likely coming from the auto trans? It drives and shifts fine.

73 Bus, 1700 type IV with original 003 automatic transmission.

Any insight you can provide is greatly appreciated. And if anyone is in the Hampton Roads area that may be able to take a look/ is very appreciated.

Thank.

-Rich

Tue Mar 19, 2019 4:34 pm

I'm confused. The only issue is the smell? Otherwise everything works fine and there are no weird noises?

Are you sure it's not just leaking oil on a hot part somewhere?

Tue Mar 19, 2019 5:17 pm

Well, yes. It drives fine and the transmission shifts smooth so I guess it's just the strong burning smell that's alarming. Almost like a parking brake that has been left on but as far as I can tell there are no rear brake issues. Smell is coming from rear of bus, but not in engine compartment. I have never smelled this strong smell before.

I suspected it was a trans issue because the smell is not a typical hot engine or oil on hot engine smell. There is a typical oil drip after the engine idling for several mins but nothing too crazy. The engine is dirty, but not crazy filthy. The smell is present after driving for a few minutes and just after she is shutdown. Then it eventually goes away. I noticed the ATF was very low but no major Trans leaks from what I can tell. Based on post it seems it is ATF in the final drive causing the low ATF in auto transmission.

By the way, I just reread the lubricant portion of the Bentley green book and see you need to remove the oil pan on the final drive the change the trans fluid in the final drive. Still don't see a ref to the lower auto trans filler tube to empty the ATF.

Tue Mar 19, 2019 6:04 pm

Do you know what hot brake pads smell like? It's a very particular smell. I am not understanding your description of draining the ATF. ATF drains when you take the pan off the transmission. It is filled through the transmission dipstick. The final drive takes hypoid oil. Did you check the ATF level with the engine running and trans in neutral?

Tue Mar 19, 2019 9:42 pm

A tubing wrench of the correct size will loosen the nut on the filler tube for you, not cheap to buy though.

If you are getting ATF leaking from the automatic section into the final drive section the automatic section may be low on ATF, while the final drive section may be puking oil out its vents. Check the gear oil level in the final drive to see if it seems over full or not.

Wed Mar 20, 2019 5:17 am

I do know what a hot brake pads smell like as I have accidentally left a parking brake on a time or two over the years. It is a similar smell, but not exactly and definitely not a hot engine smell. My wife was following behind the bus on the last day it was Driven and she said, "that smell was overwhelming. I could smell it even with the windows up."

Last night I checked the ATF fluids again. Although it is still red in color It looks a little dirty and does not have that new sweet smell, but it does not have a burnt smell. But that is based on novice opinion. We've owned this bus for almost 10 years and never changed the ATF or trans hypoid oil. I would check the ATF occasionally, never noticed it being low until recently, but it had been awhile since I last checked it. The level does not seem low since I topped it off a few weeks ago - but that could be because the final drive is full of ATF. Had it not been for the smell we would have thought nothing about it and continued to drive the bus. Again it drives and shifts fine.

I will check the final drive fluid level when I get home from work this evening.

Wild things, I will look into a tubing wrench. I may be able to get more torque on that nut if the vehicle is raised, but I'm concerned with damaging/cracking the female end on the pan. It really seems it's on there tight and looks like it may be flexing when I apply a lot of pressure. In the meantime I will attempt to drain the ATF by slowly removing the pan, allowing the fluid to slowly drain from one corner. If Im careful I may be able to lower the pan to the floor once empty so I can get to the screen. I'm sure it needs cleaning. Just not sure I can do it with the filler tube still attached.

The Green Bentley Bay manual shows a couple of different styles of auto transmissions and final drives making it a little confusing. That is why I was looking for a drain plug on the trans and final drive.

I'll report what I find out after checking the final drive fluid level.

-Rich

Wed Mar 20, 2019 6:16 am

I have heard of people dropping the pan with the filler tube attached, just remove the one M6 screw that holds the top of the filler tube to the transmission case.

Wed Mar 20, 2019 8:21 am

You should at least drain the final drive section to check the fluid.

If you run it for any length of time with ATF in the final drive you're gonna kill that trans real quick.

It should be pretty clear upon draining the final drive section whether the gear oil is diluted/contaminated with ATF.

Wed Mar 20, 2019 10:43 am

sjbartnik,

correct sir, or at least that is what I gather from reading other auto trans posts.

Funny, but I would have thought nothing was wrong had it not been for the strong burning smell. Even with the low ATF I would have likely just filled it up and continued on, especially since I hadn't checked it for a while. Like I said before, it runs good and shifts smooth. No issues as far as I can tell.

I got a spare auto trans with the bus when we purchased it years ago. Not sure of the condition, not sure if it is a 003 or 010. I believe it may have 'Checked OK' written on the top, but I can't remember now. I will need to dig it out of the garage. It may have the parts to use if the current trans is toast. We'll see tonight when I check the final drive.

-Rich

Wed Mar 20, 2019 12:00 pm

I'm no auto trans expert but I understand that there is a seal between the ATF-filled portion and the final drive. Obviously if the seal has failed you will need to pull the trans, separate the two parts, and replace the seal.

But then you should be good to go after that if you're lucky.

Still not sure what accounts for the burning smell though.

One other thing I could think of is does the trans have a vacuum modulator? Perhaps the diaphragm has failed and ATF is being sucked into the engine & burned. I don't know what burning ATF smells like but I bet it stinks :D

Again, not an auto trans expert so I don't know if this is a possibility, just throwing it out there.

Wed Mar 20, 2019 12:27 pm

wildthings,

That's what I was thinking. Remove the bracket bolt on top of the trans and set everything down on the floor under the bus. PITA to clean the pan on the floor, but unless I can get the filler tube off that is the only way I'll be able to access the screen and inside the pan for a good cleaning. Oh, and get that blue sealant off the pan lip and replace the seal with a new one which I have. Just have to track down a final drive pan seal. I believe GoWesty has them.

We'll see.

-Rich