The Stovebolt Site Forums The Shop Area Driveline 1958 apache trans or s10 T5 trans

Looking for advice....again. This forum is awesome I don't know where I would be without it. Many thanks to everyone.

Anyways, I have a 1950 3100 and will be installing a 1957 261 engine. I will be changing out the stock rear end to a 2nd gen camaro for improved cruising speeds but was wondering which transmission would be the best selection? Would the 1958 apache trans get the improvement I'm looking for and is it easier to install to the engines or do I really need the T5?

bumping up the rear to more freeway gears will give you increased top end with your 58 Apache trans (assuming it is the SM420). You need to do the math with the new gear ratio and tire diameter and figure out your rpm at cruising speed. You also need to figure out how you are going to use your truck. Your T5 may be a bit faster shifting since the internals are a bit smaller and lighter but, the SM420 is a workhorse, used in 1/2 ton up through 2-ton trucks. The T5 will probably have more evenly spaced gears, (SM420 has a big jump between 3rd and 4th).

My vote is the SM420 but, since that is what I run, I may be a bit biased!

I have a 59 3100 with a 261. I replaced the original 3 speed with a world class T-5 from a Camaro. Only modification to the trans was to enlarge the 4 mounting bolt holes to 1/2 inch. Changed the clutch disc to match the splines on the output shaft. It made a world of difference when driving on the highway, lowered the rpm's about 1,000 rpm's at 60 mph. I have the original 3:90 rear end in the truck.

Smoother less sloppy shifting with the T5. Fuel mileage may improve and driveability might also improve with the T5. If you want period correct then the SM420 will have to do.

I would guess that the T5 would make it seem like a modern truck with 5 gears. It would be nice and easy to shift. I have a sm420 in my '59 and most women and kids can't even drive it. I like it. I like winding it out in third and I like the granny gear. I really like the super low reverse. The T5 would definitely be an upgrade but so would a new Silverado. I guess I just like the old everything. I bet that didn't help you a bit.
Ps. If your original transmission is a three speed, almost anything would be a tremendous upgrade!

I installed a T5 with a tall shifter handle and short-throw spacer. I've only driven it around the neighborhood (below 45mph). I really like it so far. It was an easy conversion.

Not having been on the freeway yet, I have begun to ponder whether this 4 leaf spring truck should really be given the gears to go faster than the manufacture ever intended..... I have yet to experience what it will be like at say, 80 mph (the flow of commute traffic in the first 2 lanes where I live!). Will it be a handful?

Tommy, I have read where a T5 from anything other than an S10 truck will have issues with clearing the bench seat. How well did the Camaro T5 fit. Because of this I have limited my search to S10 trucks and its been difficult to locate ones with mechanical speedometer. The closest I have found so far is a T5 for a 4x4 but it has a torsion box that I dont need and I have no idea if it would have fitting issues.

Genewiseman, Thanks for the info about explaining the ease of use between the two trannies. I have promised my daughter she could drive it sometimes......still cant believe I agreed to that, but it needs to be relatively easy to operate.

Norcal Dave, Can you tell me what type of vehicle your T5 came out of?



Thanks everyone for the information! I think i have been convinced to go for a T5.

I am not sure what is so hard about driving an SM420. My wife drove the one in our 59 Suburban for 20 years with no issues. I had a 79 Blazer rear in it with 3.40 gears, (also changed out front end, added power disc brakes , and different leaf springs) and I could cruise at 90mph all day long with no issues. True, an OD may be nice to drop rpm at that speed and maybe pick up some gas mileage but, again, it depends on how you are going to use the truck!

Dongray, I would see if there is someone close to you that has a truck with an SM420 in it that will let you drive it. You may find that it is not a big deal and you like the granny gear!

I have a '62 C10 with a 327, SM420, and a stock 3rd member 3.90:1 rear end.

I have no trouble running down the freeway at 65-70mph all day long, with occasional bursts of 75-80mph. Both my wife and daughter can drive and shift the SM420. Granted, it is easier for me, but I have a lot more experience with it.

My wife used to drive a Chevette with a 4 speed, so she has experience with a manual, but it's been a while. My daughter learned to drive in the '62, but prefers her Harley.

If you plan to use your truck as "a truck", then keep the SM420, it's bullet proof. If you plan to use it as a freeway driver, then I would consider upgrading.

Dongray,
I specialize in T5 transmissions. I like to help folks figure out how to get them working in older Chevy trucks.
Your dilemma is a good one. I have a few bits of advice. The advice given so far is good stuff.

1. Figure out what rear axle gear you have. (The 2nd generation Camaro rear if you have settled on that).
2. Use THIS RPM CALCULATOR to figure out what RPMs will be for 65 MPH. You'll need to know the rear tire diameter. Use 0.73 for the transmission ratio because that's a common T5 OD gear.
3. If your Camaro rear axle gear is higher than 3.42 (lower numerically) then a 0.73 OD gear will not work very well. You'd probably be happier with the SM420.

Multiple factors need to be considered before deciding to use a T5. A T5 from 1992 and earlier will bolt right up to a bell housing with a Muncie bolt pattern. The 1993 and earlier S10 T5 has a Muncie bolt pattern as does the 1992 and earlier Camaro T5. Later model T5 trannys have a FORD case pattern.
As you are aware, the S10 T5 with a cable speedometer connection is very hard to find these days. I used to find one or two a year but not any more. So if you want a working cable driven speedometer on your dash, the SM420 is the easier answer.

First things first . . . . what is the rear axle gear in the Camaro rear?

Don, my T5 came out of an S-10 and has a mechanical speedo drive.

Mike, yeah I think that swapping in a different front end is probably a good idea if you intend to go faster...I have the stock front suspension.

Lugnutz,
I reviewed your T5 transmission page and immediately book marked it. It is a treasure trove of information thanks for putting it together. In regards to the rear end the one I am currently looking at is a 3.73 from a 78 Camaro. Im not too sure about tire size as of yet and tend to like between 26 to 29 in. dia.


I found a 1985 S10 T5 with mechanical speedo and a 0.73 ratio on craigslist and they are wanting 700! Sounds pricey to me and I wouldnt be able to inspect it since it is several states away. It seems that the T5 with electric speedo can be found for around 300. If I have to spend that much for one with a mechanical speedo I could buy a newer model and the digital converter for the same price. Thoughts?

I have to admit I had no idea how much each component, rear end, trans, and tire diameter were so intertwined in making this decision. I have to thank everyone for educating me on this.

Dongray,

I forgot about that,sorry. Yes the camaro transmission has the shifter at the rear of the tail shaft housing, the S10 is at the front. I did swap the housing to move the shifter wasn't hard to do.The trans I used I believe was a 1992 v8 version ,so the input shaft did Not need to be shortened.It is an electric speedometer ,but I just use a gps to see how fast I'm going.