[Steve Barcak]

I've been driving my '78 Y88 with ST-10 now since August with 3.42 rear gear. It has never shifted well/easy as I remember they did. So, perhaps something is worn on the trans. I do not think it is a shifter issue.
So, as much as I do not like the gearing, etc. Am toying with idea of buying a 5 speed. I said I would not do that but, with time and thousands of miles, am thinking about it again.
So- I would like to know if any of the 5 speed OD trans are super simple to swap in? I have enough other projects at this time and do not really want to work much on the Y88 right now but, a smoother shifting trans and an OD would be super nice.
Has anyone done this swap from 4 speed to 5 speed? It appears I would not have to mess with - bellhousing, clutch assy , clutch linkage.
How does it fit under the car?
How about using stock 4spd console?
Is shifter location a problem? it says there are 3 shifter locations
what about drive shaft, cross member, speedo hook up?
anything else I am over looking in this possible swap?
I really want comments from those who have either done the swap, and/or who is driving a 70-81 with a 5 speed.
I know there are different 5 speeds avail The tremec seems the logical choice but, it also seems there are 2-3 different versions of them.
I like the one that has a lower 1st gear than my ST-10 and an OD
thanks for sharing any experience you may have.
Not really looking for opinions of those who have not actually done the swap.
SB

[tom s]

Steve the new one does not require a A body to cut the floor.I have a TKO 600 in my 421 Tempest with the 2 something first gear and like .67 OD with a 3.64.In my 69 bird I have a TKO500 with 3.27 first with 3.31s in the back and the .68 OD.Tom

[nUcLeArEnVoY]

Get the new Tremec TKX. They're purpose-built for restomods and classic car swaps, and switching it over is almost seamless on the 1970-1981 F-body platform.

https://americanpowertrain.com/shop/...d-5-speed-kit/

[Steve Barcak]

Originally Posted by nUcLeArEnVoY

Get the new Tremec TKX. They're purpose-built for restomods and classic car swaps, and switching it over is almost seamless on the 1970-1981 F-body platform.

https://americanpowertrain.com/shop/...d-5-speed-kit/

I am a Pontiac man and , thus, support businesses who support the Pontiac hobby. So, Butler Performance would be my first choice as to where to purchase a trans. Also, I do not need a 'kit' as my car already has a 4 speed. I just would need a trans/shifter
Will check your link though- can always learn something. thanks

[FrankieT/A]

You need a clutch disc that is 26 spline if yours isn't already, a cross member, a Ford C6 trans yoke and shorten the drive shaft a a minimum.

[tom s]

Steve,Butler is not the trans place Amercian Powertrain is a good one.I think my last one came from I think Hurst Drive line.Pretty straigh forward if you get the new one.As said,shorten drive shaft,26 spline disk and ford spline input yoke.make sure you chose the shifter location for your body style.The speed will go in from the drivers side.Move trans Xmember.Tom

[Steve Barcak]

My TA, as all others from the era, uses a 26 spline input so, that should be simple. It looks like the Tremec TKX is the trans I would want. Just wondering if anyone here has one in their 70-81 Firebird? and how it fits

[FrankieT/A]

I have a TKX in mine, just put it in last month. Before that I had the Keisler 700. And before that a Muncie. So going to the TKX was a little easier for me since the Keisler is more similar to the TKX than a Muncie. It fits good but still needed a little adjustment of the shifter porch, but the tunnel itself clears. When I did the Keisler I went to a 3.5" drive shaft and 1350 U joints at the same time back then.

You're basic choices now are using the TKX in stock form and an offset shifter or companies like SST that remachine the tail-housing and use their proprietary shifter that puts the shifter to the side. The TKX (and the Keisler 700) has the shifter in the middle of the trans and the Muncie bolts to the side, that difference has to be made up somehow especially if you have a console. I have had both systems and I have mixed emotions about both.

When I had the Keisler with the machined set up I had a problem with the shifter and had to deal with their proprietary parts luckily I was able to fix it but by then Keisler was out of business if it were a worse situation who knows. The offset shifter seems to rattle at certain RPM'S and load conditions, but if the offset shifter fails I can replace it or build one myself if I have to.

[FrankieT/A]

I wouldn't count on moving the cross member...

[Steve Barcak]

Originally Posted by FrankieT/A

I have a TKX in mine, just put it in last month. Before that I had the Keisler 700. And before that a Muncie. So going to the TKX was a little easier for me since the Keisler is more similar to the TKX than a Muncie. It fits good but still needed a little adjustment of the shifter porch, but the tunnel itself clears. When I did the Keisler I went to a 3.5" drive shaft and 1350 U joints at the same time back then.

You're basic choices now are using the TKX in stock form and an offset shifter or companies like SST that remachine the tail-housing and use their proprietary shifter that puts the shifter to the side. The TKX (and the Keisler 700) has the shifter in the middle of the trans and the Muncie bolts to the side, that difference has to be made up somehow especially if you have a console. I have had both systems and I have mixed emotions about both.

When I had the Keisler with the machined set up I had a problem with the shifter and had to deal with their proprietary parts luckily I was able to fix it but by then Keisler was out of business if it were a worse situation who knows. The offset shifter seems to rattle at certain RPM'S and load conditions, but if the offset shifter fails I can replace it or build one myself if I have to.

Thanks for your input. Question on shifter/console. Have stock console that has opening in middle but, using the ST-10 with shifter on the side and a handle that has 2 90degree bends in it. I would want to mae sure I could use my stock console.
do you have a certain shifter handle you would recommened to utilize the stoc console?

[FrankieT/A]

Originally Posted by Steve Barcak

Thanks for your input. Question on shifter/console. Have stock console that has opening in middle but, using the ST-10 with shifter on the side and a handle that has 2 90degree bends in it. I would want to mae sure I could use my stock console.
do you have a certain shifter handle you would recommened to utilize the stoc console?

There's a million different shifter handles you could use. A good base line would be what you would use with a Hurst Competition Plus.

[nUcLeArEnVoY]

Originally Posted by FrankieT/A

I have a TKX in mine, just put it in last month. Before that I had the Keisler 700. And before that a Muncie. So going to the TKX was a little easier for me since the Keisler is more similar to the TKX than a Muncie. It fits good but still needed a little adjustment of the shifter porch, but the tunnel itself clears. When I did the Keisler I went to a 3.5" drive shaft and 1350 U joints at the same time back then.

You're basic choices now are using the TKX in stock form and an offset shifter or companies like SST that remachine the tail-housing and use their proprietary shifter that puts the shifter to the side. The TKX (and the Keisler 700) has the shifter in the middle of the trans and the Muncie bolts to the side, that difference has to be made up somehow especially if you have a console. I have had both systems and I have mixed emotions about both.

When I had the Keisler with the machined set up I had a problem with the shifter and had to deal with their proprietary parts luckily I was able to fix it but by then Keisler was out of business if it were a worse situation who knows. The offset shifter seems to rattle at certain RPM'S and load conditions, but if the offset shifter fails I can replace it or build one myself if I have to.

So what measures would need to be taken to run a TKX without even noticing there is an aftermarket trans when inside the car? In other words, still using the factory shift lever and knob and factory 4-speed console?

[FrankieT/A]

Its right there in your quote.... The middle paragraph.

An original GM shifter regardless of car does not allow the handle to be detached. So, you would use any handle you would normally use when replacing a factory shifter, like if you were to add a Hurst Competition Plus to a Muncie or BW ST 10.

["QUICK-SILVER"]

Originally Posted by FrankieT/A

An original GM shifter regardless of car does not allow the handle to be detached.

I've used a feeler gauge blade, to release the spring clip, and slide the handle out of the shifter on my 79.

Question is... Is the flat part of a factory handle long enough to drill two mounting holes for a aftermarket shifter?

Wouldn't be hard to modify and make it work
Clay

[Steve Barcak]

Originally Posted by FrankieT/A

There's a million different shifter handles you could use. A good base line would be what you would use with a Hurst Competition Plus.

what handle did you use? and would you share a pic of it installed? thanks

[Steve Barcak]

Last week I went ahead and bought one of the new Tremic TKX 5 speeds. It looks like they have been out about 15 months now. Of course, there are different places to purchase but, being a Pontiac guy, I wanted to support Pontiac businesses so, bought from Butler Performance.
It came the other day via fed ex.
Will be making measurements/comparisons between the ST-10 and the Tremec.
Next step is to buy the Ford style slip yoke they use and have a driveshaft shortened.
Not sure how soon I will install but, within the coming weeks. Am really looking forward to the lower 1 st and OD onthe hiways. Hoping it was a good investment.
I opted for the close ratio version with the taller 5th gear.

The stock ST-10 has a 2.43 low.
Here are the ratios of the trans I bought- 2.87, 1.89, 1.28, 1.00, 0.68

https://butlerperformance.com/c-1395...rformance.html

[tom s]

Steve,it will turn out to be the best thing you EVER do to your car!Tom

[Steve Barcak]

Originally Posted by tom s

Steve,it will turn out to be the best thing you EVER do to your car!Tom

thanks Tom. am looking forward to enjoying the TA even more.

[Steve Barcak]

I have learned to really dislike ( will go as far as saying hate ) driving the manual trans in city driving and traffic. Such a pain and miss the auto in my GTO. But, still moving forward with the 5 speed swap. It is just about ready to put in. Bought a shifter handle I think will fit and I will like, Bought a C6 slip joint and brought it to a driveline shop along with another drive shaft. They rebuilt , shortened and balanced it. The speedo adaptor is the last thing and will arrive any day now. I see no reason to replace the crossmember, an uneeded expense. Am sure I will like the lower 1st gear and the OD but, driving a stick in traffic is such a pain in the butt. On the open road, no problem.

[mgarblik]

Steve, please keep us updated with your TKX swap in your TA. I am very interested in the results and your driving impressions. I like the ratio choices you made. I am strongly considering the same swap in my 62 Catalina. It has a non-original Muncie in it now and the new engine I am building for it will probably break the countershaft and case if I drive it very hard. OD would be great on the power tour in the future.