The Stovebolt Site Forums The Shop Area Driveline Getting ready for a T5 purchase, have a few questions

I've decided to ditch the Saginaw tranny and go forward with a T5 for my '47. I have an 8.5" with 3.42's and am going to use 235/75-15 tires (29"). The engine is either going to be a stock 250 inline 6 or a mildly modified 250 with flat tops, a small cam, headers, and 4 bbl intake & carb. The one that I have needs a rebuild, and if I go with that one, it will get the above mods. I'm trying, though, to convince a good friend out of the bone stock one that runs perfect from his '72 Nova. He already told me I can have it when he puts a smallblock in it, but he's a bit of a procrastinator for his own stuff since he has two shops that he runs (plus has 2 drag cars).

Anyway, I've read tons about the swap and have printed off lots of info with tag numbers and so forth. My question is this: is there any T5 that can bolt to a GM bellhhousing (which I already have from a 250) without an adapter plate? I'd like to just bolt on and be good, but am still unsure which one I can do that with and which one needs modified or needs an adapter. I will be using a new stock flywheel for a 250 and a stock bellhousing for a 250. I've gotten some parts recently from a local (large) salvage yard, and they have a bunch (15-20) T5's on the shelves for sale (around $250-275?) from various S10s. I've done the RPM calculator many times, and I'm thinking that any of the ratios would work with the 3.42's. I just wanted to have the process of bolting up to be as easy and simple as possible. Any thoughts are appreciated.
Thank you.

Wayne

BTW, I saw Lugnutz recent (and very imformative) post about this subject, so if there are multiple T5's to choose from, which would be the best (most economic) one to start with?

A few build pics:
Truck pics

I think a pre '86 T-5. You may have to grind the splines on the input shaft a little farther back. I believe that the Astro Van clutch disc works for the swap.

Thanks Don.

Wayne S,
I believe I have your answer. I have gone through the same decision making with my own truck.

My truck has a 250 from a '71 C10 and it's all stock. I'll be using a 1965 C10 3.73 rear diff. I have considered using a 3.42 rear that's leftover from my 1966 C10 parts truck, so I have done the calculations for that one as well.

I will be using my factory 1965 cast iron bell and clutch linkage too.

Please allow me to be so bold as to tell you what to do rather than simply list your options. I'll try to convince you I know what I'm talking about later. LOL!

Your 250ci and 29" tires will work best with a 0.86 OD gear if you keep the 3.42 rear. Plain and simple. That means you need a 1993 or earlier T5 from an S10 or S15 truck and it should have a 0.86 OD gear (I do NOT trust the charts that list TAG#s and gearing and I can prove that many are wrong - so beware of this and check the T5 gearing before you buy). Neither the Camaro or Astro vans have the 0.86 OD gear.

If you have a 3.73 rear and 29" tires then you can use a 0.72 OD gear but not anything taller like the 0.63 in the V8 Camaro T5.

I say this because my forum friend Ryan has a '67-'72 model C10 and a 3.42 rear with his 250ci and he says that his 0.72 5th gear will bog the engine on hills (usually).

First, I'm going to assume that you will not be driving your truck over 70MPH that much. That's just my assumption so I could be wrong.

Calculations show that a 29" tire and a 3.42 rear with a 0.72 OD will have the engine doing only 1854 RPMs at 65 MPH. That's not too bad but if traffic or a hill slows you down to 55 MPH then you will only have 1569 RPMs and will need to downshift. So you will only have a sweet spot for OD from 60-70 MPH.

I think OD should allow you to use the truck at highway speeds from 55 thru 70 without downshifting. A 0.86 OD gear with a 3.42 is right in the sweet spot for a 29" tire. That combo gives 1874 RPMs at 55 MPH, 2045 RPMs at 60 MPH, 2215 at 65 MPH, and 2385 at 70 MPH.


Here's a list of what will bolt up to your bell without any modification.

Astro van or Safari van T5 (all of them are non-WC) will bolt right up. Astro/Safari T5s come with a 4.03 or a 3.50 first gear and a 0.72 or 0.73 OD gear.

The V8 Camaro or V8 Firebird T5 from 1982 thru 1992 will bolt right up as well because the IS is the correct length. If you want to keep your bench seat then you will need to remove the Camaro tail housing and do the S10 tail housing modification. You can see how I did mine on my website. One other problem here is that many of the V8 Camaro T5s have a 0.63 OD gear which will definitely bog unless you have enough torque at low RPMs to carry it. A good thing about the Camaro T5 is that just about every V8 Camaro T5 from 1982 thru 1992 has a cable speedo drive. If you ditch the bench seat and bring the shifter up through the truck floor in the Camaro position then no modification would be needed and you could keep the cable drive speedometer.

I CANNOT confirm what I am about to say next. I have a V6 Camaro T5 and the splines on the input shaft seem to be cut along most of the length of the input shaft. Simply cutting off about 3/4" from the end should (I want to emphasize SHOULD) allow it to bolt right up without an adapter plate. So theoretically, a V6 Camaro T5 might only need a bit nipped off the IS and then no adapter plate. It will also need the S10 tail housing swap if you use a bench seat.

In summary, I think you would like the drivability of a 0.86 OD gear with a 3.42 rear and 29" tire. There are ways to get around the $160 adapter plate but I have no personal experience. The toughest thing about using an S10 T5 is finding one with a cable speedo output. If you have upgraded to a newer electrical impulse style gauge, then shopping for and finding a decent T5 should be fairly easy and more economical.

I have a passion for the T5. Please feel free to PM me and I will be happy to help if I can.

Wow! Good info there. Thanks Lugnutz. I'll address some of the main points in order:

-I was actually leaning towards a 0.86 OD trans...it seems to be the best one.

-I will be on the interstate with the truck on occasion...being close to I81 and a 70mph posted speed limit. But I don't think that would hurt the 250 buzzing along around 2500-2600 rpms (73-76mph). I have a new Speedway Mustang II front suspension with tubular arms, dropped spindles, and cut 425 # springs, and 3" lowered S10 leaf springs in the rear with a new pair of 40# coilovers from a Dodge Caravan since I don't have much room for suspension travel (plus I get them for $20). So the suspension should allow the truck to be stable at interstate speeds.

-I think finding an Astro T5 is probably like finding a needle in haystack. I've never even seen one before. But you're right, it would be a good one to find, even with the .72 5th.

-I've seen a couple of F-body T5's around for sale, but I've avoided them because of the seat issue. I'm not using the stock bench seat, but I am using a split (40/20/40) bench seat out of a 2004 Cadillac DeVille. It has the integrated seat belts in it, and it also has power adjusters, heated, memory, and is a darkblue leather. the center seat has an under-seat compartment, flip out cup holders, and the back folds down as an arm rest and also has compartsments. I was looking for a LeSabre split bench, but this one is the same size and has the neat extras. Oh, and I got it all with all the wiring and switches for $100. After, I prep a few spots in the floor, I'll be making the base frame so I can attach the seat points to it...that's the only challenge, as the seat mounting points are a little odd and different from the inside to the outside and front to back.

-That's not to say I couldn't swap tail shafts, but I'm not sure what's the better route, use an S10 box with an adapter, or an F-body box and swap tail housings...decisions...

-I think I'll be using new style gauges from New Vintage USA, Woodward line, that has an electronic speed sending unit. They seem to fit my build.
New Vintage USA Woodward gauges http://www.summitracing.com/parts/nvu-37253-02/overview/

-As far as the V6 Camaro T5, was that still a pre '93? I would assume since what I've read is that anything after that has the Ford bolt pattern.

I might head back to that salvage yard soon and see if they'll let me look over the ones they have on their shelf and check all the tags and verify by spinning the shafts.

Lug, I really appreciate the time you took to write down all of that info. We'll keep in touch about this topic.

Wayne

Wayne, not about the T5 swap, but you will like the Woodward gauges, I have them in my T bucket and love them and how they work, very accurate to boot.

Good to know. I want to have the tach built in and there are only a handful of companies that make the dual 3-in-1 type of gauge. More are coming out all of the time, but when I found these, I liked the style, how and where it's made, and the price. I also like New Vintage USA's 1940 Series line...like this - 1940 Series in black

I have a collection of T5s. My V6 Camaro T5 is WC and has essentially the same gearing as a T5 from a V6 S10 truck. It has a 4.03 first gear and a 0.76 OD. My custom V8 Camaro T5 has a 0.73 OD but a more favorable 1st gear of 2.95.

I have never heard anyone complain too much about a 4.03 first gear and that's what you will find in most S10 trucks.

Assuming that you end up getting a T5 from an S10, be it a 0.72 or 0.86 OD, I think the adapter plate is the way to go. My friend in Atlanta used an adapter plate with his and is pleased. The extra $$$ spent on the plate can be recouped if you ever swap to a different tranny.

Here's an interesting thought. Swap the S10 input shaft out and install a V6 Camaro input shaft. The longer splines on the Camaro shaft theoretically will relieve the need for an adapter plate. Just need to shorten the IS length a bit.

Another modification is doing the same with an Astro IS, but it's already the correct length.

As you can tell, I enjoy thinking about all the possible minor modifications.

I have the names of a few shops that can probably ship you a nice T5 that's ready to install and matches your needs. Let me know if I can help.

Thank you, I'll keep that in mind.

Lugnutz, the end of the shaft that needs cutting, is that the skinny part that goes in the pilot bushing?

52Carl,
I hesitate to give advice on cutting the end off the input shaft, but the answer is yes. I have never done it. Many I have talked to have done it successfully. I have a junk S10 input shaft and I intend to cut it and see how well it would work.

What I say below is heresay, not first hand experience. I don't want to tell you things and then have you go and ruin an otherwise good transmission.

Tom Langdon sold an S10 T5 to a friend of mine and just before handing it over, he went and cut off about 3/4" from the end of the IS. So I guess Tom Langdon knows what he's doing. He also told my friend that he'd need to partially grind down some of the clutch disc inner splines to improve the travel. You see, the IS splines are not cut along the length of the shaft far enough for this application. Some people I've talked to have hand ground extra length to the IS splines.

A V8 Camaro and Astro van have the correct length IS and splines so no adapter plate is needed.

The S10 T5 has an IS that's too long. Some correct this with the adapter plate and just bolt it up that way.

Others cut and grind and get by without the adapter plate.

I intend to add write-ups on the process for each modification, but for now I need to keep working on finishing my truck build.

Lugnutz; Do you know if the Camaro and Astro van are the only two with the correct IS spline count and length? Also do you know many bolt patterns there are for the bellhousing end of the T5 and what will fit a 228 bell housing.

I know about the S10 85/96 box, is supposed to the holy grail, and I'll keep my eye out for one, but I'm in the UK, so if there is any chance I can widen the net, all the better.

Even if it's hacking boxes to up to make one that fits.

thank you muchly

A direct bolt on requires a V8 Camaro/Firebird T5 or an Astro/Safari van T5. Those transmissions have the correct length input shaft and that is why they do not need an adapter plate. The V8 Camaro has a 26 spline IS and the Astro has a 14 spline. I have heard that you can take a 10 spline Jeep T5 IS and put it in an S10 (as long as the gears are the same) and that will allow you to keep a 10 spline clutch disc. I do not know if the Jeep IS is the correct length or not.

An S10/S15 truck T5 has an input shaft that is about 3/4" longer than the V8 Camaro and Astro examples above. Some people cut off the 3/4" and modify the input shaft splines or the clutch disc splines, or both. Other folks just buy an adapter plate that moves the T5 back about 1/2" to 5/8" and that corrects the situation.

I know nothing about a 228 bell housing, so I can't comment on that.

As far as bolt patterns go, the T5 has a Muncie pattern from 1982-92 for the Camaro and 1982-93 for the S10. I just learned today that some Astro T5 transmissions have a Ford pattern case. Mine has a Muncie pattern.

The 1993 and up Camaro T5 uses a FORD pattern case
The 1994 and up S10 T5 also uses a FORD pattern case.

Just this week I was looking at some photos and found something interesting. I talked to the owner of the bell housing in the photo below. He said the bell was from a Camaro with a T5. The bell clearly has the markings of a FORD case pattern T5 on it. The bell also has a small block Chevy pattern where it bolts to the block. So I am thinking you could use a 1993 and up Camaro T5 (FORD pattern case) with an older truck as long as you use this style bell. The bell has another set of holes that probably match a Muncie pattern.

Camaro bell with a FORD pattern - mates with a FORD case V8 Camaro T5

I am virtually certain that a V6 Camaro T5 can be made to work without an adapter plate as well. The splines in the V6 Camaro input shaft are cut much more along the length of the input shaft. Cutting off 3/4" would make the shaft the correct length. The input shaft should not need any other modifications.

Here are a few photos to compare.

S10 and V8 shafts. This photo shows that the S10 shaft is LONGER and that the splines are not cut long enough for the necessary clutch disc travel like they are on the V8 shaft.

Here's an Astro T5 IS. The notes are from the owner and I cannot verify accuracy but they look correct. This has the correct length IS and does not need an adapter plate.

This is a V6 Camaro input shaft. Other than being 3/4" longer than the Astro shaft, it is identical. The splines are cut along the length enough that cutting it shorter should be the only modification needed.


Lastly, the 82-92 Camaro T5 has a cable style speedometer drive but the shifter is at the wrong place to use in a bench seat truck. It can be used OK with bucket seats. The 1982-86 or possibly 1987 S10 and S15 has a cable style speedometer and these are getting very hard to find. If you find one, then the tail housing can be used on any other T5 and a small modification can be done to make the T5 have a cable style output. The 1987 and later S10 has an electric pulse speedo output which will work fine if you use modern style speedometer gauges that read a pulse.

1983 S10 Tail Housing with cable speedo output.

1985 S10 T5 This is a 1985 S10 T5 I bought last month. I was lucky to find it. It has a cable speedo output and you can see it also has a removable ratio adapter (Stuart Warner 0.733333) that slows down the speed of the cable for speed correction.

Lugnutz,

I have an 86 Astro t5 that has the ford bolt pattern,The # 's are 1352-164. I also grabbed the bellhousing when I got the trans.,It is off of a 4.3 v6. The gears are 3.50, 2.14, 1.39, 1.00, and 0.73 for the overdrive, it has the electric speedometer connection.

Just to alert you that the astro vans did come with the ford pattern in addition to the gm pattern transmissions.

Who do you get your build kits from?

Tommy

Tommy,
Thanks for the heads up about your T5. I'm still scratching my head. I learn stuff every day. It is humbling to say the least.
Since Borg Warner was making a Mustang T5 in 1985, I guess they could have chosen to use a Ford case for an Astro. It seems odd for them to do that since they were already making a Chevy pattern case since 1982, but I guess they can do anything they want.

I am curious, is your Astro T5 a world class unit?

My 1989 Safari van T5 was in a 4 cylinder van. It has a 4.03 1st gear and 0.72 5th.

Check out my website and find the rebuild page. You can see the rebuild kit as well as my step by step rebuild there. I got my kit from Tranparts Warehouse.

Since you're talking swapping input shafts, how does one do that on a T-5? I've got one, but never worked on it yet, enjoying reading the thoughts/comments so far. Does the input shaft just pull straight out if you pull hard enough?

lefty1,

You don't want to just pull it out. You would have to remove the bearing retainer first, but if you just pull it out, there are bearings that will fall out. Don't want that to happen. Look at Jays page and info, it is explained very well how to do it .

lefty1,
Like Tommy says, don't remove the input shaft unless you follow the proper steps. Otherwise the roller bearings will drop down into the case.

This next photo shows the design of the IS. It has a partial cutaway to allow clearance of the cluster gear during installation onto the mainshaft.

The cutaway portion is seen at the lower section of the IS piece in my hand and is slid into place with the orientation I show in this photo. Of course, this photos has everything outside the case for clarity.

IS with cutout area lined up with cluster gear.

As far as swapping the IS goes, you must match the tooth count for each. If the original S10 IS has 21 gear teeth (we're talking teeth here - not splines) then you would need to swap in another IS with the same tooth count. You might think that it might just be as simple as swapping in an IS from a V8 Camaro or Astro van, but that does NOT work unless the gear teeth count is exactly the same.

If I could swap a Jeep IS into an S10 T5 and eliminate the adaptor plate and wouldn't need to cut the shaft or lengthen the IS splines, then I guess I'd do it.

If I'd still have to cut the Jeep IS short or use an adapter plate, then I see very little benefit to swapping. Sure, you could keep your 10 spline clutch disc and original pressure plate, but that's all.

This next photo shows the IS in my hand with the cutaway near the bottom. The gear visible through the hole in the case will mesh with the IS. The cutaway must be lined up with that gear for clearance during installation. Removal requires removal of the bearing retainer and then lining the cutaway up with the cluster gear. Then it can come out. The roller bearings inside the IS may or may not fall into the case during removal, so having the case lid off is recommended.

Line up IS cutaway with cluster gear.

Disclaimer: I don't know why, but I have a passion for the T5. I'm not an expert. I learn new stuff all the time. Before I rebuilt my T5, I watched professional videos about how to rebuild them and was given professional advice. I'm confident that I understood and did each step correctly. I welcome you to visit my website T5 PAGE which has a large section devoted to the Chevy version of the T5. I have gathered a lot of good information there and I hope to add more as my knowledge increases.

Jay

Hi Lugnutz,
You mentioned you knew of some shops that would be willing to ship a good T5 transmission. I'd need one with the mid-shift setup plus the shifter and preferably the driveshaft yoke. Do you think any of them would have this? I have a 1952 1/2 ton with a 235. If you want to discuss off-forum my email is [email protected]
Best regards,
Jon

It's got a Muncie 4 speed (SM420 I think) fitted. So....




(Loads of info to digest Cheers)

Jon,
Dave Reed passed suddenly last year, but his shop is still going. I think the family still runs the shop. I have a forum friend who is very happy with the custom built T5 from Dave's shop.

Reed's Classic 4 Speeds
(I think his family still has the tranny shop going)
81 Ridgeland Circle
Wallingford, CT 06492-2120
203-265-6888

Tom Langdon has a waiting list but he supplies them and I know 2 happy customers.

Here's Tom's website. You'll need to call and ask about getting one and he probably has a waiting list.
Tom Langdon's website.

I know a fellow with a transmission shop in Atlanta, Ga who builds a lot of T5s for the Mustang crowd. He can build a Chevy T5 for you. He helped a friend of mine and was very professional. His name is Stan. Tell him I sent you.

Website for Stan at Pro-Force Performance

Jay

Shox Dr,
If your bell housing will link up a Muncie 4 speed, then I am certain a T5 will bolt up. The bearing retainer on a T5 is about 4 + 5/8" where it indexes with the bell and I'm not sure what the index hole size is for your bell.

IS bearing retainer measurments

My 1965 cast iron bell

Bell on the engine.

T5 trial installation

Jay

Thanks much Jay,
I'll do that. I've talked to Tom Langdon in the past but gee...it has been a few years now. He's a friendly guy as I recall. I think I'll start with him. Any suggestions of what you'd look for to mate with a 235 (1959 year engine)? The rear end is a 12 bolt out of a 1969 Chevy pickup (3.07 ratio). I have a Saginaw 4 speed here (first gear ratio is 3.11). I replaced the front & rear seals, o-rings and the gears look very good in it, but while I'm doing all this I'd go for a T5 if a good one could be had and sell the 4 speed. For what it is worth we've owned the truck since 1977 and it has always had the stock 3 speed and closed rear end. It has not been lowered, altered, or anything like that and it does not see hard work.
Jon

I think your engine will need the 0.86 OD with a 3.07 rear. I have a friend with a 67-72 truck and 250ci and a 3.42 rear and his engine tends to bog on hills with his 0.72 OD gear.

I would reconsider using a different gear ratio. With a 3:08 you will have a hard time maintaining your speed on a flat road with either OD ratio T-5. A 3:42 would be a minimum that I would use and a 3:73 would be the perfect choice in my opinion.

I think 0.86 OD would be the only option with a 3.08 rear. Depending on driving conditions and engine performance, you are correct, it might bog the engine.
Calculations show 2066 RPMs at 65MPH with a 28" tire and 3.08 rear. That should work, theoretically. A 29" tire would give 1995 RPMs.

I'd recommend swapping the tranny first. Drive and see how well the combo works. If 5th gear bogs, then just drive it like a 4 speed and get a 3.42 rear later.

Thanks for your ideas.
In the 1959 235, the max torque (217 ft pounds) was reached at 2000 rpm. In some year's models, the max torque of the 235 wasn't reached until 2400 rpm or maybe a bit above that. I'm rebuilding the engine at this point, also. I've been thinking anything around 2000 rpm or slightly above should be reasonable. Were you folks thinking otherwise and if so, why? To this point I've been concentrating more on the overall 1st gear ratio. Most people have told me anything over 9 for an engine like the 235 should be ok...higher if you plan on pulling trailers or carrying loads. Do you agree on this?
Jon

The 4.03 1st gear would give you around 12. The Camaro 2.95 X 3.08 would barely make 9. The tire size will make a little difference too. I would think the S10 4.03 would not be too low.

For example: With 28" tires and a 3.08 rear, then you could reach a speed of 20 MPH before shifting. RPMs would be at 2979 at 20 MPH in 1st gear.

One more thing Jon,
Consider this fact. Right now, with 28" tire, 3.08 rear and a 1:1 final gear (3 speed or 4 speed), you should have 2402 RPMs at 65 MPH.

If you swap in an S10 T5 and your engine bogs with the 0.86 OD gear, then swapping the rear to a 3.42 would prevent bogging BUT the end result will be almost zero gain (a drop of only 108 RPMs compared to your current setup).

Here's why.

1.0 final gear with 3.08 rear at 65 MPH = 2402 RPMs

0.86 final gear with 3.42 rear at 65 MPH = 2294 RPMs

I'd hate for you go to all the work and expense of swapping and not have a better driving truck.

The way I see it, if the 0.86 and 3.08 rear combination doesn't work well, then don't bother putting in the 3.42 rear. You wouldn't gain much.

That is actually a very good point, Jay. 108 RPM isn't going to make any difference, is it? I took another look at the rear end this afternoon, and it is in fact a 14:43 ratio (or 3.07). So at least the GM code book had it right.

I think the best thing is to see how it does with the 3.07 rear and the 4 speed and then take it from there. After all, 3.07 v 4.11 is a hair over a 25% reduction. As long as I've owned the truck, I've felt it was at the absolute least 20% over geared.

Thanks again for your help.
Jon