All about 1950 and the life of my 1950 Chevy Styleline Sled

T-5 Tranny for 47-54 6cyl trucks

from stovebolt: http://www.stovebolt.com/techtips/t5tranny.htm

I see so many questions on installing S-10 T-5 transmissions into old trucks I thought I’d write down my experience and offer it as tech reference. Instructions are for installing in a Advance Design model truck (’47 to ’53) but I think would be very similar for other years. This is not a straight forward install, particularly the clutch — beginners may not want to tackle this swap.

The tricky parts of this swap are putting together a clutch package and finding the right ratio’s tranny for your purpose. These trannys don’t have a great reputation with muscle car enthusiasts who run them with V-8′s, but they seem to be adequate for a 6. Mine has worked fine for 15 K now behind a 235.

Application sources

The T-5 was used in many applications: from 5.0 Mustangs to Jeeps to Vegas. They have the poorest reputation from the first two applications. The one you want for your truck should be from a 2 WD S-10 as the shifter in these variants is located nearest the front. It’ll make you as happy as finding a great cheap car insurance deal. It will locate the shifter about seven inches behind the stock 4-speed in AD trucks. Other variants will locate the shifter in the bench seat. You can use another variant and change the shifter location by bolting the tail shaft housing from an S-10 to it. The shifter is part of this housing so it will be located in the S-10 position. This seems to be your only option if you want a close ratio box from a V-8.

Ratios

The close ratio uses a 2.95 first gear and is best if you want performance set up. 2.95 is what the stock three-speed uses for first in the ’50. The info I got from the Chevy dealer shows 2 ratios available from ’85 to ’90 in the S-10 though there may be others: ML2 code in the glove box is 4.03 first and 2.37 second; ML3 is 3.76 first and 2.18 second.

I use an S-10 box with a 4.03 first. 4.03 is great for occasional steep driveways or creeping in a field but I usually start off in 2nd gear, which is 2.37. This will require some slipping the clutch at takeoff but works good for me. However, it will not give you a great launch if you want to do stoplight competition.

Another option is a box with 3.55 first gear. To me, this seems to be in-between the two and a compromise but I have heard some say they like it with a 3.73 rear. I prefer a 3.90 rear which will cruise 65 at 2100 RPM but will also pull hills OK in OD at 50. Also watch your OD ratios. I ended up with one early model box that had a .9 OD ratio. Hardly worth shifting into OD. Most are .72 but best to mark the input and output shafts and count revolutions.

An early box with mechanical speedo is a plus. I hear it’s very expensive to change from electronic to mechanical speedo drive. I find S-10 box’s plentiful for $50 to $100 at swaps, but the V-8 variants with 2.95 first seem to run more, around $200. Junkyards are very expensive places to get these. If time is on your side, shop around. Penny Saver-type papers are also a good source.

Before you install it…

After, or preferably before you purchase, it’s good to take a peak inside before you install. You can’t just pop a cover off to inspect these, you must pull off the tail shaft housing and shifter to get the top cover off. As long as you’re doing this you may as well at least re-shim the end play off the main shaft. They use tapered roller bearings and any end play will result in sloppy bearing clearance as in sideways play. One might consider bearings and synchro’s at this time also. Instructions are in Chilton’s at your local library. Also good time to change the speedo drive gear if necessary. You might not have to do this if you’re using a 3.73 or taller rear but I did with the 3.90. The S-10 used only one drive gear (9 teeth I think) but I found the Camaro T-5 had the right gear. I used GM P/N 14071731 (7 teeth drive gear) and 14077086 (driven gear) for my ratio of 3.90 and tire size of 28.8 inches. This will vary for different applications.

Also remove the C-clip from the rear of the output shaft. I don’t know the purpose of it but found it interfered when I used a particular drive shaft; could not slide it far enough forward to install. Some simple mods will need to be done to the tranny. Ream or drill the 4 mounting holes to open them up from the metric size to half inch. You will notice the input shaft, the pilot part of the shaft and the front bearing retainer are longer than the stock tranny’s. I cut about 1/4 of an inch off the pilot to match the stock one. This still leaves the overall length of the shaft a little long but was not a problem. You can drive the pilot bushing in further if it does interfere. I also cut the bearing retainer to match one from a stock tranny.

And now, the Tricky Part…

I found the tricky part was putting a clutch package together. Notice the splines are shorter than your stock tranny. They are also different size and number. S-10′s are likely 1-inch, 14 teeth, V-8 boxes are fine spline. Mine was 1-inch 14 so I used a 11-inch flywheel and an ’85 Astro Van 11- inch disc with a pressure plate from a small block. Used a throw out bearing from an SB but for a cast iron fork. Use the stock fork and clutch linkage. This setup put me within about .100 of running out of clutch splines on the input shaft. Enough to dis-engage but barely. I think if I ran out of splines I would have ground down the clutch disc hub a little. This is a gray area and I recommend setting everything up without a pressure plate installed so you can see what’s going on for clearance. I found some Astro Van discs very different from others. Any other make disc could work as long as it matches your input shaft and is the right thickness.

The gearbox is a couple inches longer than the stock one so you will need a shorter drive shaft. For my ’50 with the ’55 rear I found an Astro Van shaft fit perfectly with a Napa 348 cross over U joint for the rear. Again, this may vary for your application. Also needed a longer speedo cable. I’ve run the T-5′s and Saginaws with no trans mount several thousand miles with no problems, the trucks mount on the bell housing. It did however make me nervous with aluminum case sticking so far out in space so I fabricated a cross member from the original truck’s cross member. I cut and welded a recessed pocket in it, also cut and welded in tubes where the bolts pass through the vertical part of the cross. I bolted the mount to the tranny first and then slid the cross under it and bolted it on. Again perhaps not necessary but makes me feel better.

Fools the best of ‘em

Most people at shows think I have a stock 4 speed. I used a 4-speed shifter welded onto the S-10 shifter. This does make for a long throw but I’ve heard of people reoperating the shifter pivot to address this. I acquired a Hurst after-market shifter with a short throw I plan on installing.

With the T-5 I can cruise 65 mph at 2100 rpm and still pull hills at 50mph without having to shift out of OD. I don’t hesitate to drive to a show or vacation hundreds of miles away. 65 to 70 is about all I feel comfortable doing in the truck and I still prefer a state highway to the interstate. Ratios are a gray area of this article. I make recommendations based on what I like and others may prefer different ratios depending on geographic location, engine, cam, how you plan on driving, towing, importance of gas mileage vs. performance.

4 responses

  1. netsfr1

    http://www.transmissionadapters.com/Chev%20235%20six%20cylinder%20to%20Chev%20V8%20Style.htm

    TRANSMISSION ADAPTERS

    216/235 /261 Chev 6 Cyl To Chev V8 style automatic transmission

    Installation Instructions

    These instructions assume that the installer has more than a small amount of mechanical skill and know how.

    While performing this installation, please remember a few simple rules.

    (1) Install all bolts in a particular sequence before tightening any.

    (2) Never force anything.

    (3) Lubricate bolt threads.

    (4) Trial fit everything to make sure it will fit. See rule #2.

    Kit contents

    1. Block adapter plate w/starter mount

    2. Custom 168 tooth flywheel

    3. Bolt kit (6x 7/16x14x1 inch flathead screws and 6x 7/16x20x3/4 inch flywheel bolts)

    4. Stagger bolt starter-same as starter for 168 tooth flywheel from 350 Chev engine.

    This kit will fit all Chevrolet straight 6 engines built 1962 and older with a 6 bolt crankshaft. 1963 and newer straight 6 engines do not need any adapter. The 1955 thru 1997 Chev V8 transmissions will already bolt right onto the 1963 and newer 230/250/292 straight 6 engines.

    With your transmission removed, clean the back of the block where the adapter will contact it. Make sure both alignment dowels are in place. If you have three alignment dowels remove the one on top. Bolt the adapter plate to the block with the 5 flathead screws. Due to the differences in engines over the years, it may be necessary to fit the plate to the block. They weren’t all made exactly the same. You may need to grind the block slightly where the weld on the starter bracket contacts the block. Also check where the starter bracket touches the oil pan. Some pans hit the bracket. If this is the case, grind either the bracket or the pan rail. This is a tight fit. This is so there will be a rock solid starter mount. Now install the provided flywheel using the 6 flywheel bolts provided. It only goes on one way and is a tight fit. This flywheel has an O degree mark on it for timing. You should now be able to bolt any Chev automatic transmission to the back of this motor. This kit is for use on motors with a 6 bolt crank only. GMC takes a different kit. This kit is designed to use a stagger bolt Chev starter from most V8s from the late 60s to the early 80s. Just as long as it is for a 168 tooth flywheel. Chev only had 2 different flywheel patterns for many years. A 153 and a 168.

    Important! Check to make sure that the pilot on the torque converter you plan to use will fit into the crankshaft. Many of the 216/235/261 engines had an inside crankshaft diameter of 1.686. The standard torque converter pilot on a GM converter is 1.702. You will have to remove some material on the converter pilot to get it to fit if this is the case.

    Bendtsen’s Transmission Center Inc. 763 767-4480

    13603 Johnson St NE, Ham Lake, MN. 55304
    bob@transmissionadapters.com

    November 11, 2010 at 6:17 am

  2. netsfr1

    BUFFALO
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    (360) 652-7684

    Transmission Adapters:

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    235/261 to Powerglide, Turbo 350 & 400, Scattershield
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    GMC 228/302 to Powerglide, Turbo 350 & 400, Scattershield
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    November 11, 2010 at 6:18 am

  3. netsfr1

    That adapter is for an auto tranny. You need an adapter that bolts an S-10 5 speed tranny to your bell housing. One place to find the adapter is Buffalo Enterprises in Washington State. I believe there are other places to find the same type of adapter. The early Nova or Camaro is a good choice for the correct fit rear. The 55 to 57 Chevy rears are also good choices. Some may suggest changing your stock bell housing for a truck bell. The easiest way is to find the correct adapter and keep your stock bell housing. All in all a good swap if you want the 5 speed.

    November 11, 2010 at 6:19 am

  4. netsfr1

    http://www.adchevy.com/techtips/t5swap/

    Home :: Tech Tips for Classic Trucks :: T5 Transmission Swaps for Stovebolt 216, 235, and 261 Chevy Inline Six Engines
    T5 Transmission Swaps for Stovebolt 216, 235, and 261 Chevy Inline Six Engines

    View all Tech Tips…

    On of the most popular upgrades for Advance Design trucks, is the installation of a late-model 5-speed T5 transmission in place of the original 3 or 4 speed gearboxes.
    Choose your T5

    The Borg-Warner T5 transmission was widely used by various auto manufacturers over the years, but we are primarily interested in those used in the Chevy S10 trucks and Astro vans from the mid 80′s. These particular gearboxes use the same bolt pattern as your Chevy Stovebolt engine, and have manual speedometer outputs capable of driving your original (or aftermarket) speedo.

    The main thing to consider in choosing your T5 is gear ratios. If you are changing the gearing in your rear, you will want to keep that in mind. Use a calculator to find the best ratios for you, while taking engine RPMs, differential ratios, and tire size into consideration.

    Please see our T5 Information Page for information on gear ratios and Borg-Warner part numbers.

    T5 transmissions can be found at junkyards, but you may get find a better deal in the local classifieds or an online auction.
    Get Ready

    The Chevy T5 gearboxes will bolt right up to your Stovebolt, but you will need to do a little massaging to get everything to mesh. Firstly, you will need to find a clutch disc with the correct diameter and the right number of splines to fit the input shaft of your T5. Most T5′s use a 27-spline input shaft, and you can buy clutch discs to fit this from most local auto parts stores (Napa, Advance, etc…). Measure your original clutch disc and try to find something of the same diameter.

    The input shaft on your T5 will be slightly longer than the original transmission. Use a feeler gauge to precisely measure the difference. You can either trim the extra length off the end of the input shaft, or create a simple spacer to fit between the transmission and bellhousing.

    Finally, remove the T5 bellhousing from the transmission (if you have it) and drill out the 13mm holes in the transmission with a 1/2″ drillbit to allow the bellhousing bolts to fit.
    Chevy 216 Stovebolt

    A 1985 Borg-Warner T5 overdrive transmission bolted to bellhousing of a 261 Stovebolt
    Install It

    Your T5 should now bolt up to your Stovebolt bellhousing. You should be able to use the original throwout bearing, clutch fork, and pilot bearing with your T5. With the right preparation and a little luck, the whole thing will go together and you’ll have a working clutch!
    Finishing It Up

    The T5 gearbox is a few inches longer than the original transmission, so you will need to make some modifications to the driveshaft. Many people choose to replace or upgrade the rear axle at the same time and getting a custom driveshaft built to fit, but you may be able to get your existing driveshaft shortened at a driveline shop. You will also need to find a slip yoke for your T5 if you don’t already have one. This may also be a good time to eliminate the Torque Tube if you’re interested.

    November 11, 2010 at 6:20 am

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