1963 Powerglide Option

[Richard P.]

When I bought my '63 Powerglide coupe it had absolutely no paperwork. No way to tell what options it should or shouldn't have. I have always assumed that the Powerglide option included only the trans and its associated linkage, fluid lines, cooler etc.. Is it possible it might have included positraction or was that always something that had to be ordered separately? Thanks!

[Larry M.]

Re: 1963 Powerglide Option

When I bought my '63 Powerglide coupe it had absolutely no paperwork. No way to tell what options it should or shouldn't have. I have always assumed that the Powerglide option included only the trans and its associated linkage, fluid lines, cooler etc.. Is it possible it might have included positraction or was that always something that had to be ordered separately? Thanks!

It DID NOT include posi-traction rear axle. That had to be ordered separately.

Larry

[Bob R.]

Re: 1963 Powerglide Option

I believe all powerglides came with a 336 rear differential but you could order positraction separately

[Richard P.]

Re: 1963 Powerglide Option

Larry/Bob: Thanks for the confirmation.

[Andreas S.]

Re: 1963 Powerglide Option

I believe all powerglides came with a 336 rear differential but you could order positraction separately

I have a 63 with a 327/300 and a powerglide transmission. Would my differential have 3.36 gears or do I need to have someone check the code?
Thank-you

[Joe L.]

Re: 1963 Powerglide Option

I have a 63 with a 327/300 and a powerglide transmission. Would my differential have 3.36 gears or do I need to have someone check the code?
Thank-you

Andreas------

All 1963 Corvettes with Powerglide transmission were originally equipped with a 3.36:1 axle ratio. Of course, this can be changed, with or without change of the carrier housing (i.e. the stamped part). Your car has had 53 years for such a change to occur. So, you never know.

[Andreas S.]

Re: 1963 Powerglide Option

Andreas------

All 1963 Corvettes with Powerglide transmission were originally equipped with a 3.36:1 axle ratio. Of course, this can be changed, with or without change of the carrier housing (i.e. the stamped part). Your car has had 53 years for such a change to occur. So, you never know.

Thank you Joe. I will check the code but was curious and am personally not to get under there. At least I know what the gearing should be and I doubt it has ever been changed. 32 years in my possession. Was told it needs a new pinion gear and think it might be a good idea to do the whole rear end while we are at it?

[Duke W.]

Re: 1963 Powerglide Option

Thank you Joe. I will check the code but was curious and am personally not to get under there. At least I know what the gearing should be and I doubt it has ever been changed. 32 years in my possession. Was told it needs a new pinion gear and think it might be a good idea to do the whole rear end while we are at it?

Differential pinion or drive pinion? There's lots of bad advice offered by commercial repair shops. You'll do yourself a favor by posting whatever symptoms you detect that indicate the axle needs to be overhauled. In addition to checking the numbers there are some basic checks you can do yourself to determine the health of the axle.

[Joe L.]

Re: 1963 Powerglide Option

Thank you Joe. I will check the code but was curious and am personally not to get under there. At least I know what the gearing should be and I doubt it has ever been changed. 32 years in my possession. Was told it needs a new pinion gear and think it might be a good idea to do the whole rear end while we are at it?

Andreas------

You cannot replace just a pinion gear. If, indeed, the pinion gear does need to be replaced, you have to replace the ring gear with it as a set. Of course, if one has the differential out of the car to replace the ring and pinion, one should definitely go through the entire unit.

[Andreas S.]

Re: 1963 Powerglide Option

Differential pinion or drive pinion? There's lots of bad advice offered by commercial repair shops. You'll do yourself a favor by posting whatever symptoms you detect that indicate the axle needs to be overhauled. In addition to checking the numbers there are some basic checks you can do yourself to determine the health of the axle.

Just had my car at an internationallly known restoration shop. No names mentioned. Due to physical limitations, I cannot perform the work and must rely/hire a professional. The problem was suppose to be repaired but now I am left to deal with it. (long story) The car has had a "clunk" when going into gear since I bought it. Transmission was totally gone over (taken out) and no issues. They told me it is the pinion gear.

I don't know the difference between the drive pinion and differential pinion?

The car drives fine but has the clunk which they simply told me was the pinion gear with no adjustment left? I don't know but I really want to get it fixed.

Thank you

[Andreas S.]

Re: 1963 Powerglide Option

Andreas------

You cannot replace just a pinion gear. If, indeed, the pinion gear does need to be replaced, you have to replace the ring gear with it as a set. Of course, if one has the differential out of the car to replace the ring and pinion, one should definitely go through the entire unit.

Fully understand.

[Russ S.]

Re: 1963 Powerglide Option

How bad is the clunk. My 73 with TH400 has always clunked when put into drive especially if the idle is a little high. My 66 PG also does with everything rebuilt.

[Andreas S.]

Re: 1963 Powerglide Option

How bad is the clunk. My 73 with TH400 has always clunked when put into drive especially if the idle is a little high. My 66 PG also does with everything rebuilt.

Thanks for your response.

I have also been told by others that this clunk is not unusual. I'm trying to verify this, as it has been doing this for 32 years and now I'm being told it's the pinion gear. It is more noticeable at high idle, as you say. I will try to get an audio video when I am able which should help to hear it. I have had everything apart under the car but have never had the differential open. I don't want to open it if it's not necessary.

[Duke W.]

Re: 1963 Powerglide Option

Just had my car at an internationallly known restoration shop. No names mentioned. Due to physical limitations, I cannot perform the work and must rely/hire a professional. The problem was suppose to be repaired but now I am left to deal with it. (long story) The car has had a "clunk" when going into gear since I bought it. Transmission was totally gone over (taken out) and no issues. They told me it is the pinion gear.

I don't know the difference between the drive pinion and differential pinion?

The car drives fine but has the clunk which they simply told me was the pinion gear with no adjustment left? I don't know but I really want to get it fixed.

Thank you

If a commercial shop told me that, internationally recognized or whatever, I would certainly question what they meant by such a vague and confusing statement. If the axle is Positraction, clutch wear increases differential pinion gear backlash and yoke end play. This can be easily checked on a frame lift. It's unlikely that ring and pinion backlash has changed unless a drive pinion bearing is spalled in which case you would hear a steady "growling"or "scraping" noise from the axle.

Another source for the "clunk" when you go from Neutral to Drive could be deteriorated from axle mount cushions that allow excess axle movement from torque reaction or even loose bolts that mount the bracket to the axle housing. This is easy to check on a drive-on lift by cycling between Neutral and Drive and watching for excess movement of the bracket relative to the axle housing or frame. These cushions deteriorate over time, especially if the axle has a history of pinion seal leaks as the oil will rapidly increase the rate of deterioration.

I suggest you get at least one other opinion, if not two or three, and a knowledgeable person about these cars who doesn't do commercial work, like someone from your local chapter, would be a good choice because they have no financial interest in any required repairs.

Duke

[Andreas S.]

Re: 1963 Powerglide Option

If a commercial shop told me that, internationally recognized or whatever, I would certainly question what they meant by such a vague and confusing statement. If the axle is Positraction, clutch wear increases differential pinion gear backlash and yoke end play. This can be easily checked on a frame lift. It's unlikely that ring and pinion backlash has changed unless a drive pinion bearing is spalled in which case you would hear a steady "growling"or "scraping" noise from the axle.

Another source for the "clunk" when you go from Neutral to Drive could be deteriorated from axle mount cushions that allow excess axle movement from torque reaction or even loose bolts that mount the bracket to the axle housing. This is easy to check on a drive-on lift by cycling between Neutral and Drive and watching for excess movement of the bracket relative to the axle housing or frame. These cushions deteriorate over time, especially if the axle has a history of pinion seal leaks as the oil will rapidly increase the rate of deterioration.

I suggest you get at least one other opinion, if not two or three, and a knowledgeable person about these cars who doesn't do commercial work, like someone from your local chapter, would be a good choice because they have no financial interest in any required repairs.

Duke

Thank you for your advice and opinion

I will definitely be getting some others to look at it as you say.