[engineer9]

My 62 Cat has a "Slim Jim" auto trans that I want to replace and have considered a TH400; however, I am not real excited about having to modify the tunnel to get it to fit. I have heard that a TH350 will fit without modifying the tunnel. I DO NOT intend to race this car and will only drive it for cruises and shows, so a "super robust" tranny is not required. If anyone has installed a TH350 in a '62 B-body, I would appreciate learning what the required modifications to the tunnel (if any), trans mounting member, and driveshaft are.

[Dick Boneske]

I put a TH400 long shaft in my '62 years ago. Not a lot of hammering was required to make it fit in the tunnel. I used the existing cross member for the rear support. It needed to be moved back until the bolt holes on the trans matched.

Do you have a later block in the car that the starter will bolt to? If not, this is a more major problem.

[stevep]

The 350 will work just fine with slight mods during the rebuild. If you aren't rebuilding it, it will probably still be fine as long as you aren't totally hammering it.
You can run it without the kickdown cable if you have to.
The 400 is the better choice.

[Steve Barcak]

I have put 400thms in a couple of my '61 Catalinas ( same floor as your '62). It is not a big deal to fit the floor. I know some guys have had to pound the floor but I never have had to. Not sure why that is.
A 350 turbo trans is a good trans for your application.

I agree with Dick, Pittsburgh and Steve though. The 400 will be a better choice and you don't have to mess with a kickdown cable. Pontiac 400 thms are plentiful too. Either a short or a long tail will work.

Either way, you will like your '62 better.

Steve Barcak www.pontiacheaven.org

"Real Pontiacs only...no corporate nonsense!"

[455HOGT37]

Does the 63 share the same tunnel? Because I had no issues putting a TH400 in mine (63).

[uk61catman]

Hi from the UK.I'm also wanting to replace the Slim Jim in my '61 Catalina Convertible,could one of you guys send me the info regarding the swap and what is needed please.
I believe that I can acquire a brand new and crated,ex US Military TH475 transmission for very little money,is this just a heavier duty 400 ?
I can be reached at colingibbard@btinternet.com thanks

[engineer]

bigger question is what did you all do about the starter mounting?

[PITTSBURGH 64]

And thats the $64,000 question......................

Wil-Cap has the adaptor.
http://www.wilcap.com/pontiac.html

Well worth it to get rid a Jim!

[Jeff Walker]

Originally Posted by uk61catman

I believe that I can acquire a brand new and crated,ex US Military TH475 transmission for very little money,is this just a heavier duty 400 ?

Yes it is. internally the biggest difference is that the TH475 has straight cut planetary gears as opposed to the helical cut planetary gears in a TH400. Depending on the application the TH475 may have a unique output shaft and extension housing as I have seen some in motorhomes that were mounted to the back of the transmission. But the 400 output shaft and extension housing will fit the 475 trans. Also the TH475 will most likely have a Chevy bellhousing pattern, but adapter plates are made to fit the Chevy bellhousing transmission to BOP blocks.

HTH

[uk61catman]

Thanks for the help guys ! I knew that there was more to getting rid of a Jim than people in the UK say.I've been telling them but they don't listen !

[Dick Boneske]

Getting rid of a Slim Jim is worth the effort--whatever it takes. I can't imagine what GM was thinking when they put this trans in the '61-'64 Pontiacs and Olds'. My '62 GP was absolutely terrible to drive with this trans. When it shifts from first to second, it feels like someone bumped into your rear. When they die, which can happen any time you're driving (and will), getting the car towed, finding a trans, installing it, etc., etc. is a REAL hassle. Once you put a TH400 or TH350 in your car, you'll wonder why you didn't do it sooner. Finding a '64 or newer Pontiac block with provision for starter mounting should not be a huge problem, even from the UK.

[stevep]

The Slim-Jim was an Oldsmobile design that looked GREAT on paper. That's why all 1961-1964 Olds' had them but only the short body Pontiacs got them. I guess that PMD had their doubts.

We just rebuilt one in a 62 Starfire conv and it worked out great... but it cost the guy a LOT of money.

Get rid of the Slim-Jim, your car will thank you every time you drive it.

[carcrazy]

In the past, when I had a few automatic 62's, I was on a first name basis with my tranny guy. The slim jims just didn't hold up-even when you weren't pounding on them. One my last one, I changed to a turbo 400. Used the original crossmember but if memory serves me correct some modification was needed. I had a later model 400 motor so didn't have to deal with the starter issue.

[uk61catman]

Thanks everyone for your assistance with this.Will I be able to use my original starter or get one of those mini hi-torque ones ?
A buddy of mine has a completely overhauled 700R4 that he'll let me have for the equivalent of about $90,or a good condition TH400 for $45 from a '77 TransAm that was broken up.I drove the car before it was parted out and it worked okay !
Finally,will I need a different driveshaft or need to get my original altered and balanced ?
Thanks again.

[Dick Boneske]

uk61catman,
You haven't answered the key question: Does your car have a '64 or later block so there will be a place to mount your starter with the newer trans?

[uk61catman]

Ooops,forgot to say that the block in my car is from a '63 Bonneville but I have the original '61 numbers matching one stored in my garage but not fit for recon.The starter motor mounts to the bellhousing on the 3 spd Slim Jim not the block.

[Stuart]

I have heard that some '63 engines had provisions for mounting the starter to the block but I don't know if that's true or not. It wouldn't hurt to check your engine; if it does have the mounting holes it will save you a lot of trouble since you won't need to buy an adapter plate.

If you need one, the adapter plates are available from Bendtsen's at http://www.transmissionadapters.com/ and from Wilcap at http://www.wilcap.com/.

[Engine-Ear]

" know some guys have had to pound the floor but I never have had to. Not sure why that is." -Steve Barcak

Steve, I remember Ed Giolma telling me that the '61 cross-member is different from '62s...the fuzzy/important part: the center is lower on '61s than the '62s (or vise versa)...sorry, that wasn't too helpful (just making conversation!).

I had a short-tail TH400 in my GP for a short while (before going the 4-speed route) and I had to slide the cross member to the front about 3 inches. In my case, the TH400 mount bolted into the '62 cross member's center bracket with only minor hole elongation.

[engineer9]

I appreciate all the discussion on transmission swapping; however, my original query really didn't get answered as the thread kind of veered toward the TH400 swap which I am not interested in. I'll try my original query again: If anyone has installed a TH350 in a '62 B-body, I would appreciate learning what the required modifications to the tunnel (if any), trans mounting member, and driveshaft are. Thanks!

[Fellyn]

While I didn't do the original swap, my 62 Catalina has a TH350 which I recently rebuilt and am putting everything back together. Since the neither the trans or the engine has provision for starter mounting a 1/2" steel plate was made with the bellhousing pattern and starter mount and was sandwiched between the engine and trans. A 1/2" steel crescent spacer was made to move the starter back inline with the flexplate. The torque converter was shimmed out 1/2" to engage the trans properly. A new crossmember was fabricated ( you might be able to modify another). The driveshaft I have in place is a 1310 series shaft prolly taken from the donor car so 1310/3R combo u joints were needed. It had a "custom" shifter which I replaced beautifully with a lokar column shift linkage (The column shift lever has a stud that will need to be drilled out). The kickdown cable is stock with fabbed bracketry. I didn't see any evidence of tunnel massaging.

This post has some pics and i can take some updated ones if anyone is interested. http://forums.maxperformanceinc.com/...d.php?t=533019

The only thing I'm trying to figure out now is the dipstick. The previous owner used bent copper pipe and lots of silicon which isn't gonna cut it. The stock dipstick that came with my donor trans hits the tunnel. so maybe someone can answer this one for both of us. Anyone know a stock application dipstick that will fit nicely in a 62 b body with a TH 350? Or are we stuck with one of those flexible deals?