oldsmobum

So I was out on a date the other night and the transmission quit on me. I had just pulled out into traffic and was accelerating normally, when It suddenly lost drive. It was like it had popped into neutral. I am not sure if it was during a shift (it could have been). It will not move hardly in any ranges, including reverse, however shifting from neutral to any drive range you can definitely feel the gear engage... And in gear it will barely move, at 2500+ rpm.

Is there anything I should specifically be looking for? Or maybe something from experience any of you guys have seen? I just hope I haven't broken a band or something of that nature...

d2_willys

Check the fluid level and color of fluid first. Next check the linkage to see if the shift lever is not loose. If these all look ok, then it is time to check the mainline pressure. There should be a pipe plug between the band adjustments that an oil pressure gauge would connect to. This will tell you if you have any mainline pressure. If little or no pressure, then front pump, pressure regulator, and valve body is where I would start. Since you have no drive or reverse, it seems to be more pressure related than any of the bands, clutches or hard parts. A possible test of the front pump would be to have someone push the car using another vehicle, then release, and see if the car will respond at that speed. This will use the rear pump to generate pressure in place of the front pump. If still no drive then the pressure test is where I would start.

oldsmobum

Thanks for the reply. I have a gauge that should work so I will check that one out tomorrow and let you know what I come up with. If no pressure I'll drop the pan and poke around a bit. Thanks again for the reply

oldsmobum

So I checked the pressure and even though it wasn't accurate (leak in the fitting) I got 60 psi at the gauge in drive and 160 at least in reverse... which according to the manual sounds like I could be within spec. Should I get ready to pull it and check out the hard parts?

d2_willys

The pressure check sounds like the front pump is good. So I would do the following:
1) Pull the side pan and check the shift linkage to see if the linkage inside is good to the valve body. Make sure that the detent wheel moves and that there are 5 distinct shift positions. If this is good, then replace side pan and :
2) Remove pressure regulator plug (driver side near top of transmission at bell housing) and pull out spring and plunger. Start engine and run for 15-30 seconds with a drain pan underneath to catch oil. Shut off engine and replace pressure regulator components. Try to drive. If still no drive then:
3) Drop the main pan and check for bottom of pan for anything that should not be there. Check to see if the front band is broken, as the front band would cause no drive or reverse. If all looks good then:
4) Remove and clean valve body.
It seems that the problem is common to all driving ranges. This would point toward commonly used components. Kind of weird question: Could the driveshaft or rear end be bad and the transmission is fine???

Let me know what you find out. I will check my manuals for other things to looks for .

oldsmobum

I will pull that pressure regulator. I checked the shift linkage yesterday and it seems okay. There were indeed 5 distinct positions, and it does crawl forward and reverse under higher rpm in the appropriate positions on the linkage.

I will also drop the pan if no results and pull the valve body.

You are not the first person to ask about the rear end. It was recently rebuilt for what its worth... but the car is easy to push back and forth, which to me is an indication nothing is locked up there... I guess I can crawl under there and watch the drive shaft and see if it is keeping up with the engine rpm.

Thanks again for all of your help.

d2_willys

I will check my book to find out if the pressure regulator is before or after the pressure tap. My gut feeling is that the front planetary is broken at the ring or planet carrier. Since that is used for all ranges, it seems to point in that direction. Hopefully it is something hydraulic instead.

The front planetary drives the drive torus at either reduced (1st & 3rd) or 1:1 (2nd & 4th). Front pump drives via the torus cover, so you could have pressure, but no coupling to rear planetary if the front planetary is defective.


Another test is after pulling side and bottom pan, along with valve body, is to apply compressed air to front band release port and observe the band. This can also be used to apply air to front clutch apply and release ports and observe the front clutch.

These ports are at the valve body matiing surface.

oldsmobum

So a lot has been going on lately and I haven't had a lot of time for the olds... But I finally got that pan off today. The front band is clearly broken. It will come out for a rebuild, and hopefully I can make a thread about it. I have a freshly rebuilt motor and trans for it (59 394 with a GMC hydro) That I will install when I have the funds for the nickel and dime stuff. Thanks for all the help I might need more when I crack that trans apart,

d2_willys

Is the 59 Hydro like the 55 hydramatic (side cover) or is it the dual coupling type that was coupled originally to the 394? The dual coupling hydramatic is not as performance minded as the 55 hydramatic is. I would suggest that if the later hydramatic is indeed a dual coupling type, then have the older hydramatic rebuilt and then bolt it to the 394. You will need a pilot bearing installed in the 394, and then have the older flywheel balanced, as the 394 is externally balanced. The two locating dowels for the bell housing to block will need to be updated to being installed in the block instead of the bell housing like the newer engine does. I have done this conversion many years ago using a 60 371 bolted up to a 54 Olds hydramatic.

oldsmobum

It has an iron case, and looks like it might even be the earlier type than my 55 with both bands externally adjustable... I noticed on mine only the rear is. I'm assuming this motor and trans came from a GMC truck, because the trans has a 59 date code on it if I read it right. Am I mistaken assuming the jetaway had an aluminum case?

d2_willys

The Jetaway had aluminum bell and tail housings, but I believe the main case was still cast iron.

However you have two band adjustments, so this transmission is probably older than 54, but might not be. If you can give me the tab id on the side of the trans, I can look it up. It definitely is not a Jetaway. And it is not my 371 with hydro, as mine was a 54 with single band adjust screw. Would have been really funny if you had my old engine and trans, as 371's of 59 and 60 look just like a 394.

The good news is that that transmission is hooked to some engine, Oldsmobile 394 doesn't sound right for stock trucks. If it is indeed a 394 you should be able to look at the code on the left head and provide that.

If it is a 394 with the hydro, you are in excellent shape. That would be great to be able to hook to the 55. Send some pics and I can look at them and tell you if there is anything else you need to be aware of.

oldsmobum

Thank you for all of your help. I will take detailed pictures tomorrow. As provided by the seller: eng. no. D696129, trans no. 053-17428X. The engine number doesn't sound right, I will have to check it out myself when I can. Both units were rebuilt, so unless someone messed up that process I should be sitting pretty.