47-59 automatic in a 58 apache

[forestb]

What sizes of automatic transmissions will fit in a 1958 half ton without doing any cutting?

[Rickysnickers]

I have a 700r4 in my '57, if that helps. Nothing has been cut.

[forestb]

That does help some. At least it gives me a little confidence.

[G&R's57GMC]

Also a 4L60E , TH350 , 200R4 , Aluminum Power Glide and a cast iron Power Glide .

[mr48chev]

There should be room for any GM trans that will bolt to the engine.

If you don't have side engine mounts on the engine in the truck now it would be extremely wise to install side mounts provided the engine has the pads for them. Reason being, that if you run stock front TF motor mounts at the front of the engine and a rear mount on the transmission you stand a good chance of either breaking the bellhousing or having the front seal in the trans leak due to the tendency for the whole assembly wanting to flex when it is supported that way.

[forestb]

Awesome. Thanks everyone

[_Ogre]

orrieg is the only builder i've seen not to cut out the trans x-member
the trans x-member also supports the front cab mounts
if you cut it out it needs something in place of the factory x-member

this is how i handled it in my apache when i installed a 700r4
the x-member supports the rear trans mount
the diagonals keep the frame from flexing at the cab mounts

[cameo]

Don't forget they cam with an Automatic option, the 4 speed Hydramatic. this was also used in busses and tanks

actually forget that thing it weighs more than the engine, parts are next to impossible to find, needs periodic adjustment, and has no park.

Had to be an a$$
sorry

[G&R's57GMC]

Originally Posted by cameo

Don't forget they cam with an Automatic option, the 4 speed Hydramatic. this was also used in busses and tanks

actually forget that thing it weighs more than the engine, parts are next to impossible to find, needs periodic adjustment, and has no park.

Had to be an a$$
sorry

Ahh but it did have a “park” in consumer vehicles .

Although it didn’t have a park position on the selector .

Remember when this “new fangeled” automatic transmission came out it was customary to put your manual trans in reverse when parked , why because reverse was generally the lowest gear .

So it was a natural thing to put the automatic in reverse when parked .

The 4 speed Hydramatic has a parking pawl that is held off when the engine is running and the transmission is pressurized . When selecting reverse and shutting the engine off the pawl in no longer held off and a spring pushes the pawl into engagement with the components directly connected to the output shaft of the transmission .

Start the engine in neutral and drive away in whatever gear selected .

[cameo]

interesting. the one in my 57 did not have the pawl in it.
There is a guy in Mission BC (Canada) that drag races a 4-speed Hydramatic in a 58 Impala. its a big heavy boat with 348 W-head (could be wrong on displacement, but it isn't a 409) and it looks like it could be on the strip in 1959. and it boogies.

[G&R's57GMC]

Ok it should have had a pawl or if it did maybe the spring was broken or missing .

My ‘56 had one .

I’ve run into several younger owners that didn’t know about putting it in reverse and were jumping out and putting a block under a tire . Once I told them about putting it in reverse and shutting it off they were happy truckers .

[mr48chev]

The hydromantic really isn't a great option unless you are seriously bent on restoring a truck to stone stock. Reasons being that the parts are hard to find and now quite expensive plus finding someone who actually knows what they are doing on one is getting quite hard and again quite expensive.

For me having more comfortable driving by installing an automatic also means having an automatic that I can get serviced at any legit dealer or service shop and can get serviced,repaired or replaced on a road trip in a reasonable amount of time if needs be. That means Turbo 350, 400 or one of the overdrives that are now common.

[forestb]

Thank you guys for all the help but when I asked the question I was looking at buying a 58 with a manual transmission but that isn’t going to happen. Thanks for all the help.

[daveshilling]

No worries, now you know for next time!

[mr48chev]

Better to ask and then decide it is too much work than not ask and find out that it is a lot more work than you thought.

Back in the mid 70's a lot of guys with TF trucks were buying 350's and Turbo 350's out of the wrecking yard and sticking them in the trucks using the stock front mounts, cutting out the middle crossmember with a torch and making a rear crossmember for the trans out of what ever they had be it channel iron tubing or ?? Some times pretty sketchy crossmembers as there was little or no aftermarket stuff available then. Leaky front seals in the trans were pretty common and broken bellhousings happened enough so that you heard about them without any internet. A friend showed me one in his transmission shop when I stopped by to visit.

Those were pretty quick and nasty swaps, I was around one where they drove the truck to a friend's shop in the morning with the engine and trans in the back and backed it out of the shop and drove it home about 9 pm that night and didn't really get in a big hurry doing it. I think their biggest hassle was figuring out how to mount the automatic floor shifter that came out of the donor rig so they could reach it from the seat.

[dennislbrooks]

Maybe just me. Part of my 2wd to 4wd thread using a 350TH with a np208. The transfer case does not make a difference in mine. In other words, I could not place the 350th in the truck with the rear engine xmember in place. I am not sure where their engine placement was to allow them not to cut. Mine is a 59 GMC so there may be frame differences and you may be ok.

https://www.67-72chevytrucks.com/vbo...d.php?t=808297

OK, the link where the guy put a np203 in his 59 -- put engine, trans, and transfer case on a bare frame then set the cab on it. I do not know if he could remove the trans from the finished truck without removing the bellhousing cross member.

I removed mine - had to. The cab mounts still hold the frame at that point and I left the riveted sections in for original strength. It is now like my 67 in that area. Now it also has the trans/transfer case mount and crossmember.





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[dsraven]

hey brooksie, those little nubs leftover from cutting the cross member out also make a great starting point for a new bolt on member to reinforce the frame near the front cab mounts. just something to tie the rails together so the cab doesn't need to do that job all by itself. without the brace sometimes the cab can crack near the mounts. the other thing that can happen with just the front engine mounts and the rear trans mount, without the larger spread of the original bell housing mounts, is the engine torque can cause the mounts to tear under heavy or sudden loads and then the whole thing rotates. some builds have torque limiting straps or chains in place so this doesn't happen. just a thought.

[dennislbrooks]

dsraven, I will have to ponder that.

[dsraven]

For the torque issue some guys would simply use a short length of chain bolted to the block and over to the frame. Both sides in case you do a burn out in reverse, haha.
For the cross member you are just trying to stop the frame from flexing apart or together so a bolt on affair works and is easily removed for pulling the trans etc. It also acts as a trans pan shield if your truck sits low.

[1project2many]

For the cross member you are just trying to stop the frame from flexing apart or together so a bolt on affair works and is easily removed for pulling the trans etc. It also acts as a trans pan shield if your truck sits low.

Hmm... Wondering if a K series THM 350/400/700 with 10MM bolt holes for aluminum torque converter cover and fore-aft braces would allow one to build a bolt in crossmember in similar style to original. Not often thought of and you'd have to find the right transmission.

Hard to see, but these images show the dust cover flange and bolt holes on the 80's K series THM350.

[dennislbrooks]

I do believe this pertains to this thread for an auto trans in a 58/59 Chevy/GMC. ---maybe not----

Result of ponder.

I have a low performance 350sbc in front of a 350TH. The only concern I have is that the crossmember I removed also supported the front springs rear perches...

The pic is somewhat scale from front to rear and measurements are center to center.

The 2nd crossmember back 10" from the front oem is the sbc side mount engine mount support 2" box which goes from frame rail to frame rail.

I will have to fabricate a new cross support that has to be bolt in/out that will reside under the trans dust pan about 4 inches in front (c to c) of removed crossmember. This will not be a straight shot. I cannot use the nubs left from the removed crossmember.

[_Ogre]

Originally Posted by dennislbrooks

Maybe just me. Part of my 2wd to 4wd thread using a 350TH with a np208. The transfer case does not make a difference in mine. In other words, I could not place the 350th in the truck with the rear engine xmember in place. I am not sure where their engine placement was to allow them not to cut. Mine is a 59 GMC so there may be frame differences and you may be ok.

OK, the link where the guy put a np203 in his 59 -- put engine, trans, and transfer case on a bare frame then set the cab on it. I do not know if he could remove the trans from the finished truck without removing the bellhousing cross member.

I removed mine - had to. The cab mounts still hold the frame at that point and I left the riveted sections in for original strength. It is now like my 67 in that area. Now it also has the trans/transfer case mount and crossmember.

fyi, the hydromatic trucks had a bolt-in, drop-out x-member

when i first bought 58truk the po had installed the 350/350 on front mounts and trans mount
the motor moved so much that i couldn't keep exhaust doughnut gaskets in either side
i fabricated and welded in new side mounts without pulling the motor or trans
i bolted on sbc motor mount, bolted a 3/8" pipe nipple in and using cardboard templates, cut triangles from the frame flanges to the pipe nipple
easy peasy

[dennislbrooks]

My front engine mounts are side mounts 10" back from the front oem and goes rail to rail. I think I will not add the extra crossmember and beef the added dropped rear trans/transfer crossmember to stiffen things up instead.