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:confused:When I separated my transmission from the clutch housing today I discovered there is no gasket. Is this normal? If so, where can a new one be had?:confused:

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And all along I thought was my rear seal. I do not have a gasket between the bell housing and the transmission. I am curious where would the gear oil leak out? I also noticed someone posted that you could split the gasket (most likely at the top) so that you could move the transmission away enough to slip the gasket over the input shaft, position the gasket and tighten up the transmission. If anyone has done it this way please let me know.

Thanks,

Hank :)

Trans_3-Speed.jpg

It won't take long. Just disconnect the drive shaft (at the differential is easiest for me) Remove each of the the two top bolts replacing them one at a time with the special hanger pins. Please note how the illustration does not show a gasket between the bell housing and the transmission.

DSCN1573.jpg

Edited by HanksB3B

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Truck 3 speeds don't need the Trans to bell housing gasket. The truck 3 speed is with out the open shift rail hole that does require a gasket.

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Hank,

Your trans could leak from a leaky front bearing retainer gasket. Or also a loose mainshaft in the front of the trans case. The mainshaft when installed to the front of the case should be a very tight press fit. I have seen quite a few get loose in the case and yes oil can leak from the shaft in the front of the case. A trans case to bell housing gasket will seal it as long as the case hole is 100% covered by a gasket.

Bob

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Hank,

Your trans could leak from a leaky front bearing retainer gasket. Or also a loose mainshaft in the front of the trans case. The mainshaft when installed to the front of the case should be a very tight press fit. I have seen quite a few get loose in the case and yes oil can leak from the shaft in the front of the case. A trans case to bell housing gasket will seal it as long as the case hole is 100% covered by a gasket.

Bob

In the diagram, which part # is the front bearing retainer gasket? A loose mainshaft (maybe but the transmission was recently rebuilt by a pro but I realize this may not mean anything). Which shaft in front of the case (p/n?). What area do you mean by the "case hole"

Thanks,

Hank :confused:

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Brg retainer gsk - 21-09-33

Mainshaft (gear) -21-09-2

Countershaft - 21-24-2

Diagram #s from previosly posted. Brg on the mainshaft should be sealed on the outside. Parts diagram shows a hole low on the front side of the case where the countershaft sits. May leak at that point also.

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I recently worked on a small leak from the front of my gearbox Hank. I pulled the retainer (21-09-29) off and made sure the seal inside was in good order. The gasket (21-09-33) was new and appeared fine but showed traces of oil from the 4 bolt holes. I used a sealing compound on the 4 bolts as the bolt holes continue through into the gearbox case. I haven't road-tested the truck yet but may do so on Monday if the rain holds up. The retainer (21-09-29) has a small groove at the bottom which lines up with an oil-flow hole in the center-bottom area of the main shaft hole of gearbox case, so I would imagine that it is best to make sure it goes back on the way it comes off and the groove and hole are aligned.

Desotodav

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In the diagram, which part # is the front bearing retainer gasket? A loose mainshaft (maybe but the transmission was recently rebuilt by a pro but I realize this may not mean anything). Which shaft in front of the case (p/n?). What area do you mean by the "case hole"

Thanks,

Hank :confused:

I meant to state countershaft-NOT mainshaft. Sorry for the confusion. Desotodav is right on on his info too!

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The retainer (21-09-29) has a small groove at the bottom which lines up with an oil-flow hole in the center-bottom area of the main shaft hole of gearbox case, so I would imagine that it is best to make sure it goes back on the way it comes off and the groove and hole are aligned. Desotodav

I'm not sure I paid attention to that when (about 4 months ago) I replaced part #21 09 29 with an undamaged spare I happened to have. Well to let you guys know, it is warming up so some of you snow birds will get to working on your trucks again.

Thanks to both of you for your excellent advice,

Hank :)

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All this talk of transmission leaks has caused me to revisit my minor transmission leak again.

I was visiting an Engineer mate yesterday and he raised an interesting point. He has recently used his lathe to cut a slot at either end of the transmission 'countershaft' (21-24-2) in order to insert rubber 'O' rings at either end to prevent leakage. I presently have a transmission leak from the point at the front of the transmission where the countershaft mounts into the hole at the lower front of the 'case' (21-03-1). 'O' rings which could be positioned at either end of the countershaft to press against the inside edge of the case would prevent any possibility of oil leakage from this area. It's a pity that I hadn't talked him at the stage that I was rebuilding my 51 truck gearbox, but maybe I'll consider this option for building my 55 truck.

Just a thought for those out there who are experiencing a similar problem!

Desotodav

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I really cant see the need for a gasket in that position, there should be no oil in that area, other then front input shaft and if thats leaking then the front to bell gasket wouldnt help anyway as the retainer plate sticks past. Souns like something to fight with while already trying to install the trans

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for a Solution to this problem. Want to use Amsoil Synthetic Gear Oil but with the way mine leaks using $9.00/qt oil doesn't make any sense so I'm back to drip pans and $3.99 gear oil.

Hank :(

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for a Solution to this problem. Want to use Amsoil Synthetic Gear Oil but with the way mine leaks using $9.00/qt oil doesn't make any sense so I'm back to drip pans and $3.99 gear oil.

Hank :(

Did you pull the trans and replace the front retainer seal and housing gasket? I just used ultra black on the housing/trans mount...then a new seal on that same piece where the input shaft comes through...only way to stop the leak...unless you get some ATP trans stop leak...but slim chance it would fix anymore then a weep

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Let me get this straight. Yes I replaced both gaskets 21-09-33 between case 21-03-1 and retainer 21-09-29. Are you saying that you used Ultra-Black between the bell housing and the transmission case 21-03-1?

Trans_3-Speed.jpg

DSCN1573.jpg

Thanks,

Hank :)

Edited by HanksB3B

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21-09-33 I used ultra black instead, but I'm just realizing on the diagram above there is no input shaft seal??? How is that even possible...I was refering to my T-5..I should have been more clear...but the retainer 21-09-29 should have a seal in it no??? What would stop the oil from just leaking down the shaft past the bearing...unless the bearing on this model of trans has a seal built into it?

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I believe it is a sealed bearing. I think the leak has to do with the holes in the front of the transmission. I know the retainer has only four bolts but it looks like the transmission has 5 (at least in the scan).

Hank :)

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my tranny is weeping front and rear from the big plates and the bolts a liittle bit. I drained the tranny and put the black onthe bolts and that reduced the ammount that comes out, but I still get a little weep from the plates. As someone said before, it might not be possible to truely seal these old beasts up.

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my tranny is weeping front and rear from the big plates and the bolts a liittle bit. I drained the tranny and put the black onthe bolts and that reduced the ammount that comes out, but I still get a little weep from the plates. As someone said before, it might not be possible to truely seal these old beasts up.

That's funny...the 4 speed I just removed from my 50 1 ton was dry as a bone, and it was right full of fluid...well not now..it went all over the shop floor when it tipped off the jack :P

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That's funny...the 4 speed I just removed from my 50 1 ton was dry as a bone, and it was right full of fluid...well not now..it went all over the shop floor when it tipped off the jack :P

well ok then! when the time comes to change the fluid I'm gonna look into the seals a bit more on mine....I can deal with a little leak for now.

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if anyone does the following, I'll do the latter part:

1. If someone has a 3 speed that is currently out of the truck and if someone has a 4 speed out of the truck use a paper bag or other suitable piece of paper and with a pencil (those flat carpenters pencils work best) do a rubbing to make a pattern, PM me and I'll give you my mailing address so you can fold it put it in a $0.44 cent envelope and mail it to me.

2. I will then make an overlay pattern and attach the .pdf format drawing that you can then print out, tape to the gasket material of your choice, cut out and use on your truck.

In another thread somewhere one of us split the gasket halfway (the upper half) up to the large hole where the retainer is, making it possible to pull the trans (my cut cut bolts with the slotted head would easily make this possible) away from the bellhousing just enough to slip the gasket in without removing the transmission. I'd like to try this method first as it should only take an hour more or less.

So is anyone is "down for this" (de) please let me know.

Hank :)

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The 3 speed car transmissions required the bell housing gasket for sure-trucks no. Gasket wouldn't hurt though. No input shaft seals used on the older 3 speed and NP 420 4 speeds.

Bob

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Good job gents. I'm thinking of pulling my transmission out again, but I'll probably just make a gasket to suit whilst it's out. I seem to have a small amount of fluid leaking from the countershaft hole at the front of the case, and the other leak appears to be from the retainer area. From memory, the retainer had a rubber seal ring on the inside of it and mine appeared to have a break in it.

Desotodav

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I had to visit an old thread to seek information on my latest venture.

I thought that I would work on the only remaining oil leak from my 3 speed transmission whilst it (and motor) is out of my 52 truck. I seem to have developed an oil leak from the casket between the mounting bracket for the handbrake drum and the back of the gearbox case (photo 1). I pulled the gasket out and found that it was actually in quite good shape - but I will make a new one (or 2?) and install it anyway.

My question/s to those in the know: do you think that a new gasket with some sealer should stem the oil leak from that area? Any idea why there would be 2 'gaskets 21-23-17' shown in the truck manual (photo 2) and is that where my problem is because I only have 1 installed? All of the bolts were checked and tight prior to removing the bracket. I'm thinking that maybe the gasket became saturated with gearbox oil which allowed it to seep through. Please see attached photos. All advice appreciated.

post-3915-0-74163600-1369533834_thumb.jpg

post-3915-0-75152200-1369533848_thumb.jpg

post-3915-0-85285700-1369533857_thumb.jpg

post-3915-0-27394700-1369533866_thumb.jpg

post-3915-0-15485400-1369533875_thumb.jpg

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