The Stovebolt Site Forums The Shop Area Driveline Issues with T5 swap- vibrations, etc᠁

Hi Fellas,

Ever since in installed my T5 I have been plagued with issues᠁

While rebuilding the engine, I had my flywheel re-surfaced and installed a new clutch disc and pressure plate, as well as a new pilot bushing. Transmission is a NWC T5 out of an S-10. I used an aluminum adapter plate.

I have had a little clutch judder in first gear from day one, and also have a high speed vibration that I believe I have traced to the output shaft bushing being worn- with the driveshaft installed, I can move the yoke in the transmission tail up/down/side just a little- I am assuming that there should be zero play in his area?

I did not take a dial indicator and measure around the circumference of the adapter plate or bell housing prior to installing the transmission.

I believe that I have two unrelated issues- clutch judder being caused by trans/bell housing/engine misalignment of some kind, and a high speed vibration being caused by T5 tail housing bushing/yoke play?

After nearly 8 years the truck is nearly finished, and I would like to be able to drive it!

How do I check trans/bell housing/ engine alignment? What do I do if it is misaligned???

Should the driveshaft yoke be tight in the tail housing with no play at all? If play is acceptable there, could it be my trans bearings causing the high speed vibe issue?

Any advice greatly appreciated. I want to get everything right so that I can drive this truck regularly. Restoration is almost complete᠁.

Truck info:

1950 3600 with 261, NWC Chevy T5 (from salvage yard- not rebuilt) and two- piece driveshaft removed, replaced by one piece drive shaft. A Bolt-in crossmember was also installed at the T5 trans mount location (with a rubber mount), and I noticed that the high speed vibration became worse after installing that crossmember. No vibrations at speeds below 45 mph. This was a brand new driveshaft built for the truck by a driveshaft shop and dynamically balanced.

Thank you

Did you have yours rebuilt?

I have a NWC S10 T5 behind my 216 in my 50 3100. I had it rebuilt and had a Jeep 10 spline input shaft installed by the rebuilder. Took just a little (less than 1/2") off the tip of the input shaft (based on a measurement taken off the stock 3 speed) and bolted it directly to the bell housing. I am using a stock 50 clutch. I did not put a mount on the back of the trans.

Sorry I don't have any actual useful information, only what my setup is, which works pretty well.

I did the required trimming of the trans for the swap. I am using the 14 spline input shaft. Trans was NOT rebuilt, so I am contemplating getting a rebuild kit and doing that while the trans is out of the truck.

I have 2 trucks. Both have a T5. Neither has an adapter plate. One drives like a new truck. The other has clutch shudder sometimes and I’m sensing some vibration at higher speeds.

I recommend that you go about solving this systematically.
Make sure the pilot bushing is within spec. New pilot bushings are cheap if there is any doubt.

Use a dial indicator to make sure the flywheel is perpendicular to the crank at 12, 3, 6 and 9 o’clock and that the rear of the bell is also within spec. This DIY that I wrote describes how to do these measurements. T5 installation link

If all that checks out, you should replace the slip yoke bushing inside the tail housing. The wobble should probably be a lot less than what you have now. T5 parts vendor ALSTATEGEAR

The T5 input shaft should not have any endplay. If it moves a little side to side, that’s ok. If there is endplay, then adding the appropriate thickness shim inside the input shaft bearing retainer will solve that.

The driveshaft angle needs to be correct. Typically, an engine crankshaft and transmission main shaft are pointing down 3 degrees towards the earth, front to back, on level ground. The rear axle pinion should have the same angle POINTING UP, rear to front. That way the pinion and tranny main shaft are PARALLEL, but usually NOT pointing straight at each other. It is my understanding that it’s best to avoid angles greater that 6 degrees.

Rebuilding a NWC S10 T5 isn’t very difficult and I can answer questions if you need help.

Don't have a tight u joint perhaps?

Thanks for responding lugnutz- I’m going to read your DIY write-up on checking the bellhousing and check my pilot bushing ID.

I was told by a hotrod shop to add another 2 degrees down to my pinion angle, so that when the truck accelerated the pinion would come up and be at the right angle. I spent a lot of time measuring the angles of the pinion and the trans yoke before welding on the perches᠁.they gave me some really bad advice!! I’m not drag racing᠁ I should have just set it up like you said- equal angles (parallel). I need to find someone who can make me some shims that won’t break the bank!

I should have thought about that a little more before welding on my spring perches. I can fix the angle with axle/leaf spring shims. I still think the tail housing bushing is worn though.

I have to stick with my adapter plate, otherwise I’m going to have to $pend again to build a longer driveshaft. Custom driveshafts have gotten really expensive (like everything else).

BC59-

I’ve got brand new u-joints, and checked this early on- u-joints checked out okay.

I discovered that a rear transmission mount caused noise to telegraph up through the frame and into the cab. Once I removed it (I should add it was a rubber mount) the noise almost went away. In neutral I'll still hear some noise, but I don't believe the transmission has been rebuilt.

I was taught (long ago) to add 1 degree down to the pinion angle for spring wrap. If you have 4 or 500 horsepower or if you are hauling very heavy loads, you may need 2 degrees, but if you have a 235 you won't.

That is interesting about removing the trans mount and having the vibration/noise improve. I may end up removing mine when all is said and done.

I also have “anti-wrap” spring perches that are quite long that I got from ruff stuff specialties (a local shop that makes some very nice axle swap parts). I probably don’t even need to add the 1 degree with those on my axles᠁. Regardless, I’m going to shim it and see if I get improvement at highway speeds.

So Dave, are saying you have front motor mount, side mounts at bellhousing and another crossmember & mount at the rear or the transmission?

Yes- all three. The T5 has such a long tail that it worried me having it unsupported, especially since I have a much longer driveshaft than a 3100

Caster shims should work to pull the axle into alignment. Get one of the magnetic angle finders, they are fairly cheap, and use it to check motor to driveline angle then compare that to driveline to pinion angle. 3 degrees +/- a degree or so on both ends. Having four mounting point may be part of the vibrations and clutch issues, could be not enough flex between the driveline and frame.

If you have an iPhone, you should have an app already on the phone that functions exactly like a magnetic angle finder (see photos). Having a magnetic base on an angle finder is useful during adjustment because it’s hands free, but if the iPhone shows that everything checks out, it may tell you what you need to know without buying a new tool. (I like buying new tools.)

I’ve mentioned this before but in AD trucks the front cab mount pads are usually a noise problem. The old ones are flattened letting the cab rest on the frame. The replacement pads are made from the wrong rubber and consequently go flat rapidly allowing the same problem. Solution is to get pvc shower liner material and a small can of the special adhesive used with it. Cut replacement pieces and cut hole for bolt and glue/laminate until you get the right height to keep the cab at least one eighth inch off the frame. This is the best answer I’ve found and will reduce transmitted noise quite a bit᠁and I ought to add that noise transmitted at the front of the cab can be horrible.

As for the T5 you can run without a rear mount just fine.

I run my T5 hanging off the bellhousing, 1 frt engine mount, 2 mounts on bellhousing.

When you're buying shims for the axle, make sure you are getting solid machined shims not cast iron. The new cast iron ones are coming overseas and are as brittle as glass. I installed a couple in my 49 3600 (when I did my own T5/4.3 swap) and they cracked almost by looking at them. Found some machined ones and carried on.

And it should go without saying but make absolutely certain any shim setup you use preserves the locating pin / hole match.

Good plan removing the tailshaft mount. It was never needed. The original 4 speed in 3/4 ton trucks had no support on the tailshaft. They are cast iron and a whole lot heavier that an aluminum T-5.

Thanks for the advice everyone. Looks like the rear trans mount will be removed permanently. I have a digital angle finder- so I’ll be using that again to get the shim Amit determined. And I will look for machined shims, as well.

My understanding is that when a driveshaft experiences vibration only at higher speeds, it is a dynamic problem, not an angular problem. That said, I am going to fix the angle anyway. I am hoping that I can rent a tail shaft bushing removal tool for a FLaPS. Otherwise, I will be warming up the housing and knocking the old one out (carefully).

It’s going to be a couple of weeks before I can remove the T5, but I am fairly sure I am going to find that the engine/bell housing/ trans has an alignment issue. I read Lugnutz link, and I understand how to measure , but how do you correct an alignment problem? Offset dowel pins? Sounds like a nightmare waiting for me᠁.. I have to get rid of the clutch judder though- I can manage it very well, but my wife cannot.

Offset dowel pins work, make sure your rubber engine/trans mounts are good for clutch grabbing! Driveshaft u-joints need to be phased properly!

Ed

I took a bell off of an inline 230 and found a thin metal shim on one of the bolt holes. I’d say it was as thin as a piece of paper. I imagine they must have had a way to quickly check the bell and then pull any that didn’t meet spec off the production line or the line would come to halt pretty quickly.

Thin paper is about .003” thick, same as your hair!

Ed

I think you mentioned that you shortened the transmission input shaft. That is not necessary when using an adapter plate. It's possible the input shaft is not long enough now to contact the pilot bushing. Measure that distance when you get the transmission removed. Also it's not necessary to warm up the tailshaft housing to remove the bushing. good luck

It was so long ago that I did the swap that I am not sure what I shortened, and am not sure that I shortened anything- it could it have been the tube that the release bearing slides on? If nothing should have been shortened, then that might be the problem right there- I’m going to find out soon. I’ll post my results here in a couple of weeks after I get it pulled. If I have been running it this long without the input shaft inside the pilot bearing, I am going to be flabbergasted.

Jon, as far as the locating pin goes- I’m guessing I weight have to buy (or make) a longer pin when using a shim. I have an axle swap in mine, so my setup is a bit odd compared to stock. I will post pics of that as well in my signature line.

Every T5 swap will have details that are unique to the build, but the general rules don’t change.
When bolting a T5 directly to the bell, you will try to duplicate the length of the original transmission input shaft AND front bearing retainer sleeve. See photo.
When using an adapter plate, you simply duplicate the lengths of the input shaft and front bearing retainer sleeve while the adapter plate is bolted to the front of the T5. If you want to double check before cutting, measure the distance from the pilot bushing to the rear surface of the bell with a piece of coat hanger wire.

The adapter plate usually solves 2 problems (as well as solving a bolt pattern mismatch in some cases) all at once. The S10 14 spline input shaft is too long and the splines are not cut far enough along the shaft to allow proper clutch disc movement. Moving the T5 away from the engine with the adapter plate USUALLY prevents the pilot tip from binding against the rear of the crankshaft INSIDE the pilot bushing. Also, the input shaft splines have been moved back far enough to allow proper clutch disc movement.

The attached photo shows a T5 with a Jeep shaft swap side by side with a factory 3 speed (Muncie?). Since the bolt pattern is the same, I only needed to trim back the bearing retainer sleeve and a little off the Jeep shaft pilot tip to make the T5 match the 3 speed. No adapter plate used because the bolt patterns match and the Jeep shaft splines are cut long enough for proper clutch disc movement.

The last pic shows that the depth of an S10 bell and a factory 1960’s C10 cast iron bell are identical. So the location of the end of the crankshaft in an S10 four or six cylinder engine must be the reason for the longer input shaft.

The S10 T5 transmission was used behind the 2.8 V6 which has a deeper pilot hole in the rear of the crankshaft & longer pilot bushing than Chevy inline & V8 engines.
I shorten the input shaft & front bearing retainer collar, shorten clutch hub on flywheel side.

Looks like I’m going to find some of my mistakes inside that bell housing᠁stay tuned

Hi Dave,
The best scheme is to find which shim you need to accomplish the proper pinion angle and then drill two holes through them...one the diameter of the pin bolt and another larger one to ensure the pin part of the bolt sits straight and not at an angle (which will compromise it). The best shims are already machined like this but the cheap ones aren't. The main thing is to not lose that hole to pin mating situation. You will need to buy new spring bolts...which is not a big deal. Lots of places to get them. Good luck!

I have used adjustable locating pins when installing a Tremic transmission behind a 455 Pontiac. It wasn't too bad getting them inline, toughest part was rotating the engine with the dial indicator on the crank. Once the bell housing was centered, I moved the indicator to face of the housing for the second adjustment. This is were the shim stock comes in handy. Once the second adjustment is correct, the first needs rechecked. The dowel pins worked really good, key is marking each reading at every 45 degrees, then study on it before adjusting. The Pontiac came out dead centered and parallel with the crank after a few hours of work. I used shim washer for the parallel adjustment, https://www.mcmaster.com/products/shim-washers/ring-shim-sets/

Joe

Thanks for that tip, Jon.

Sounds like a lot of work᠁but worth it in the end.

I have removed the transmission and clutch from the truck.

I am going to measure flywheel runout and bell housing alignment tomorrow. I discovered that my throw out bearing has a considerable amount of slop in it- a lot of axial play. I don’t know if this is unusual or not. See short video: Throw out bearing axial play

I measured the input shaft length and the distance to pilot bearing- everything is fine there. I did not trim the shaft or the bearing retainer when I originally installed it. As mentioned before, I have a NWC T-5 with a S-10 14 spline input shaft, installed with an adapter/spacer.

The throw out bearing was brand new when I installed it᠁. I’m wondering if the type of clutch fingers I have on the pressure plate require a throw out bearing with a curved face? My present bearing has a flat face᠁

I will post measurements and pics tomorrow.

Also, my pinion/trans angle is 2.5 degrees exactly- should i shim it all the way back to zero, or leave some amount of downward angle?

Additionally, when installed, my slip yoke sits 1.5 inches out from the transmission tail shaft housing. I think my driveshaft is too short (see pic): Slip yoke installed position 1.5 inches from trans housing

How far into the transmission does the driveshaft go? Leave tail shaft angled down if the pinion is angled up, you want them parallel.

Yes although I've always understood that you want a slight load (1/2 to 1 degree of perfect parallel) on the U-joints, not neutral.

1" travel on the slipyoke should be optimum, 1.5" is probably neither here nor there.

With the flywheel removed I checked both parallelism and clutch housing Pilot bore runout, with a dial indicator per the manual, and both are well within limits.

The flywheel face had .001”run out. Oddly, the face of it is not flat- it is cone-shaped᠁᠁..the inner segment of the flywheel surface is “higher” than the outer segment. It is significant- laying a machinists square on the section where the clutch disc sits reveals that the flywheel surface “cones” upwards towards the center of the flywheel. I’m bringing it back to the machinist tomorrow. Cone shaped flywheel surface

The driveshaft slip yoke is 3.75” long from the back of the casting’ machined face to the end of the yoke. Slip yoke

There is 1.5” of that yoke section exposed when the driveshaft is installed, which leaves 2.25” of slip yoke that sits inside the T5’s tail shaft. This doesn’t seem enough to me. Your thoughts?

You're mainly concerned a) that the yoke stays securely on the tailshaft; and b) that the driveshaft doesn't bottom out against the tailshaft. I've had a few driveshafts made (including for the T5 in my 1949) and when measuring, I was running off a recommended (by the machine shop) 1" minimum travel when the vehicle was standing unloaded on level ground. That's worked well for mine, driveshaft works like a charm. When I say "travel" that's the distance between the end of the tailshaft and the inside end of the driveshaft yoke (or the travel of the separate slipyoke if you have a fixed yoke on the output). 1" frankly doesn't seem like much at all.

If you've got 1.5" of travel and it isn't in any danger of popping off the tailshaft when the suspension is at full travel, I can't see that being much of an issue. "Should be" in no danger of bottoming that against the tailshaft either. If you have a good tight fit on the splines and the lions share of the yoke in contact then it should be darn stable.

All that said, you have to use your judgment on that since it's in front of ya. You can see better than us, if there's something going on that might change that.

My first T5 installation was in my 1965 C10. I had my original DS cut shorter by a DS shop and then the S10 slip yoke was put on with a conversion U-joint. Worked great. It was pretty expensive though.
I used a worksheet supplied online by Denny’s Driveshafts. (Just Google that name).

If I recall, I used worksheet B to get the dimensions for the DS shop to work with. The guy at the shop looked at the sheet and gave me a thumbs up. It was all he needed. Worked out great.

Years later I installed a T5 in my 1963 C10. I had read somewhere that an Astro van DS was the correct length, so I searched through my local salvage yard. Unfortunately, the salvage yard I frequent uses a large forklift to set the vehicles and damages 90% of the driveshafts.

I stumbled upon a DS just laying on the ground that was the correct length. I had no idea what vehicle it came from but it had the correct slip yoke (with a balancer). I bought a new conversion U-joint for the rear of the DS and it bolted right up. That 63 drives like a new truck and I saved a lot of $$$.

Here are pics. Research shows me the DS came from a Chevy Blazer. Not all Blazers will have the correct DS, so the sticker ID is important to match mine. I recently grabbed another DS just like it.

That could be correct. When I had a flywheel resurfaced for my diesel truck, they asked if it was supposed to be flat or tapered (cone shaped). I had checked the specs and on that particular setup the flywheel surface is completely flat.
A cone shaped flywheel would make the disk engage first in the center (on yours), and then compress against the outer edges of the flywheel. That may be done for a smoother engagement.
But I have no idea what the proper specs (flat or coned) would be for your truck. The machinist (if he's worth his salt) should know the proper setup.

Today I took the flywheel back to the machine shop and when I laid his straight edge against the flywheel, it was coned, just as I said. He took the straightedge and laid it across the surface and began sliding feeler gauges under it. He said that it was not coned, but would put it back on the grinder. I picked it up an hour later and when I do my test, it is now flat. Since I didn’t have to pay for it, I was not going to spend any more time talking about it. The flywheel is flat and in my garage now.

The clutch was another matter- I took the clutch back to the place that I got it from (they only manufacture clutches and brakes). The old guy took one look at my disc, and said “see those marks right there? That is where you stabbed the transmission in and the splines weren’t engaged᠁let me put it on the lathe and I’ll check it.” 15 minutes later he comes out from the back and tells me that the disc was warped/bent from pushing against it during installation, and that he see many like this. He straightened it (it was .008” out) and said I was good to go now. I’m not sure what to think, but my impression was that he was being totally honest with me. I don’t recall being aggressive with the trans during install, but who knows- it was over 5 years ago.

My concern about the yoke in the trans housing is that I want to make sure that the yoke goes far enough back into the housing to engage the entire bushing in the tail housing᠁

I’m still Waiting on trans parts- I’m going to rebuild the trans while it’s out.

Thank you for all the info and pics. I think I’m going to reverse my rear springs to get them back to their stock positions ( I had swapped them around to move the axle back to the center of the fender arch), this will move my axle forward and my driveshaft will then be too long-then I can have it cut to the right length. When I had the driveshaft made, my measurement was 1/4” too short. Probably not a big deal, but the yoke feels much tighter in the tail housing when it is pushed in another 1/2”. I only have about 1/2”of travel at the yoke. Pushing the yoke in another 1/2” will give me 1” exposed. The yoke just seems short to me, but I am no expert. I want to,get rid of the high speed vibration that I am having- sliding the yoke back in in the tail housing only another 1/2”gives me much less slop there. The bushing is probably worn, which I am going to resolve during the rebuild. There is plenty of room in the yoke - I can push it all the way back to the housing until it is just about touching the machined edge of the yoke.

Maybe I’m just paranoid, as the other two yokes I have pulled out of transmissions were considerably longer than this one᠁

Lugnutz- the pic of the yoke with your hand on it is the same as my yoke - but I can see that yours had been riding much further inside the tail housing. It is rusty,only about 3/4” at the end- which seems correct to me.

Also, my truck is a 3600, and so I get none of the joy that you guys get when you go looking for driveshafts- there simply aren’t any one piece driveshafts that will fit my longer frame (at least none that I could find in any salvage yard).

When installing a trans. to help engage input shaft with clutch disc, put the trans. in high gear to make it easier to turn the input shaft with one hand on the output U joint while pushing
in with the other. For those with only one hand, get a friend to help.

Ed

Mine's a 3600 as well. I don't have any wreckers left near me so don't even have the option of digging around like we used to before all the regs basically killed the automotive recycling industry up here. Luckily we have a local machine shop that does driveshafts.

With my T5 swap I went to a one-piece driveshaft with a slip yoke (the output on my T5 is a fixed yoke, cobbled together); the slightly longer wheelbase vs. a 1/2 ton is not an issue if you have a driveshaft company nearby. They will balance it too. Definitely more $$$