We're looking at a 66 gto with a 2 speed Powerglide transmission. Is it a good tranny? How durable will it be?

Question

What I'm saying is, if I want to "have fun" driving it, like the 66 gto should be driven, will i damage the tranny? I guess what I'm asking is, the rundown on the Powerglide tranny in 66 for a gto. Any help would be appreciated.

Thanks.

Answer 1

i had one in a 67 lemans. it was pretty tough. but that 1st gear was geared a little to high. didn't have much bottom end. ofcoarse my 3.08 rear didnt help either. i would yank it out and drop in a 2004-r or a 700r-4. with the 700 you will have to get an adapter. the 200 was availible with the b-o-p bolt pattern. you will also see an improvement in your fuel milage and reduced engine wear with the overdrive. and that tranny you have isnt called a powerglide. its actually a GM type 300. it has a diffrent trans fluid pan than the powerglide.

Answer 2

The powerglide is a good enough tranny, but not recommended on any GTO. If I were you, I would do lots and lots of research and be sure that the car you are looking at buying is not a GTO clone; which is just a tempest with the 396 and catalog order badges. Check the vin with and ask around at car shows and contact clubs to get the low down on what to look for.

The reason the powerglide is not recommended for any GTO is because it is a light duty transmission and with all the torque the 396 puts out in such a small and light car, if you stomp on it, you may learn the hard way how to rebuild a powerglide.

If, however, you plan on just cruising around with your girl and taking it easy and just want a fun car, the powerglide GTO's do not cost as much as the 4-speed (manual) transmission equipped cars.

Either way, 66 was a great year (one of my fav's as the 67 is just too over popular right now), and I wish you the best of luck.

Answer 3

First- Pontiac never used the Powerglide. Pontiac's version of the 2-speed auto was called the Super Turbine 300. Its an OK tranny at best for hard use. Lucky for you, the BOP TH-350 3-speed is a direct swap for it, cheap and will handle the abuse.

Also check the 8.2" 10-bolt rear end closely, as they don't take much abuse either. The 389s were good runners, make sure to run premium gas as the compression was high. You need to make sure its numbers-matching to bring top dollar. Get the Pontiac Historical Society documenation on the car to verify what options it had from the factory. I THINK all GTO vin numbers should start with 242.

good site for GTO info:

www.performanceyears.com

Edit- I beg to differ with the gentleman's comments below in one regard- I have done the ST300 to TH350 swap in my '67 Pontiac. Here's my original post on PY:

The ST to TH350 is almost a direct swap. Get a Lokar TH350 detent cable kit, a TH350, a TransGo shift kit, a new tranny mount, a better converter, and a TH350 yoke for the stock D-shaft and go to town. You'll love it. You may have to mod or replace the shifter if you want Low gear on the TH350. The shifter is only for a 2 speed, so you can only shift into manual 2nd with stock shifter.

Answer 4

The powerglide is the most sought after transmission for drag cars and street racers as well. It is extremely durable and since the transmission only shifts once you make up a few seconds right there. They're easy to install a stall speed as well which will give you more speed coming out of the hole. These transmissions were very sturdy but in the unlikely case you did strip a gear they were very easily repairable and at a modest cost. Car enthusiast still seek the powerglide transmissions. You can hardly find one in a salvage yard anymore. Hang on to it and don't be afraid to run it hard. If for some ungodly reason you do want to get rid of it. PLEASE contact me.

Answer 5

That tranny is not a powerglide it is an M31 super turbine 300. It shares no parts with a powerglide. I have a REAL 65 GTO with ac that still has its original 2 speed super turbine in it. Everyone calls them powerglides but they ARE NOT powerglides. This was a fairly common tranny in goats ordered with ac, and ac cars came stock with 3.08 open rear ends and could only be optioned up to a 3.23. Put a tremec tko600 5 speed manual in it. that will give you a first gear equivalent of a 4 speed with a 4.56 rear end but the .64 overdrive 5th gear will cruise at 70-75 t about 2000 rpm.

Answer 6

In my opinion, electron 6 is giving you the best advice. The 'glide is a decent trans up about 250 HP. from 250 to 350HP it gets dicey. No high RPM neutral drops and your probably OK. The 'glides racers use today only have one thing in common with their production counterparts, two forward speeds. to get them to live behind high horsepower drag cars they utilize re-engineered cases, gears, planetarys, etc. A race glide is an animal like no other. The 3spd, heavier duty automatic electron 6 refers to is generally an easy swap, but is not a direct replacement for the 'glide as he suggests. The overall length of it is longer and requires a shorter driveshaft and a different rear trans mount. To summerize, accelerating hard doesn't really bother a production 'glide. Hard or jack rabbit launches from a dead stop do, especially when the HP gets near 300. You should not construe this to mean that if you launch your 'glide equipped car hard it will break, but rather that the 'glide will not take as many hard launches as the 3 spd will. And a neutral drop (rev the car up in neutral to about 4500 rpm and while holding that RPM move the shift lever into low gear) will 9 out 10 times result in a 'glide grenade.

Answer 7

OK you have alot to read already... NO PG in 66

Factory is a J/NA Turbine 300 (((Junk unless you going to putt around town)))

If someone put in a Power Gluide (Buick or 67 68 69 Pontiac) You need to see if its a All Aluminum case or Steel case if you want to build it.

OR Just Get a TH350 or Step Up and get the 200r4 or Newer 700r4 Built for street strip... And pick a good converter.

Will be a Fun car to Own... GET IT....

Answer 8

66 Gto

Answer 9

I had a 66 caprice and a 67 Beaumont(Pontiac). The power Glide is just about bullet proof. As far as putting your foot to floor, and smoking the rears(stock). A THM 350 would be a better choice. If the car came with a power Glide, it will be worth more at resale.

Answer 10

Does anybody know where to get a cable for the ST300 for a 66 GTO? No one seems to make them anymore for some reason.