5 speed conversion with pics

[jodydewey]

Everyone,

I have started to convert my 1968 Chevy C10 shortbed from an automatic back to a stick. The transmission I decided to use was a NV3500 five speed from a 1994 Chevy C1500 pickup. I am going to document all the steps needed and the changes required to install this into my pickup. My truck was originally a 3 speed on the tree truck but had been converted to a TH350. The clutch pedal was hidden beneath the carpet (a nice surprise). When I started having transmission trouble I decided it would be more fun to go back to being a stick.

The first area I chose to change was the clutch linkage. The truck was originally made with mechanical linkage. The NV3500 uses hydraulic linkage. Mechanical cannot be retrofitted because the NV3500 has the clutch fork on the passenger side.

[jodydewey]

I purchased a hydraulic clutch kit from LMC for a 1994 Chevy 1500 truck. It comes with a hydraulic master cylinder, the line, and a slave cylinder. The units are assembled, filled, and bled already so bolting it in is all that is required.

[jodydewey]

The hydraulic master cylinder has to be level to work properly so the clutch rod could not be used in its present form. You may notice that the lever points down at about a 30 degree angle. This would have to change. Basically the "clock" of the lever had to change from 5 oclock to 3 oclock.

[jodydewey]

Basically there are two different thoughts: make a bracket to change the angle or - (the way I am going) cut off the shaft, rotate it, and weld it back on. I wanted it this way so that I could make it look like that was the way it was supposed to be instead of something I cobbled together. Here are the pictures of the clutch pedal before and after welding. The first picture is of the pedal assembly in the truck. Notice the angle of the bracket. The second is of the pedal in my vice. Notice the sharpie mark on the shaft. This is the angle the assembly needs to be at to work with the new hydraulic master cylinder. The next one is the pedal after I cut off the shaft and tack welded it in the correct position. The last two are of the bracket after it was tack welded.

[Huck]

Is the trans manual speedo with cable gear or elec pulsed? that was my problem with a 96' 5speed.

[jodydewey]

It is electric pulse. My plan is to switch the gage cluster to the cyberdyne blue ice gages. The cool thing about the cyberdyne setup is that you turn it on with the parking lights on and it will enter set mode. Then you bring the truck up to 45 mph and hit the set button. Then the speedo is set. No other calibrations needed. I have one in my 1990 Nissan 240sx. I used a handheld GPS to set it. Since it is so easy to set it will work with any tire/gear combination easily.

[jodydewey]

So far I have the clutch pedal finished and painted. I didnt think a picture of it would have been warranted. Hopefully my clock is correct. I am hoping that with the lever changed to straight up and down when I push in the clutch pedal it will have enough throw to completely engage the slave cylinder. Until the lever is installed I really won't know. I am waiting to continue the saga until the front end is pulled off of my truck. My engine is broken and I am pulling the entire front end off to make it easier to take the engine and transmission out and also give me room to work the clutch master cylinder. I also thought while it was off to weld off all the holes, paint the firewall, and put in new inner fenders. I figured while the whole front end is off the pictures will be much easier to work.

For the other questions, an NV3500 will NOT take huge amounts of torque. Maybe 350 lb/ft tops. No dropping the clutch or power shifting. For how I drive though it should be great. I am really stoked about putting it in so I can get overdrive.

[jodydewey]

OK. I finally got the front end off and the engine and transmssion pulled. You do not have to go this far to do the swap. I just did it because my inner fenders were severely rusted along with the radiator core support. Plus having the front end off makes the engine pull soooo much easier.

[jodydewey]

I installed the clutch pedal back into the truck with the updated clock. I found that I had to grind my weld a little better so it would fit. I also had to widen the bolt slot in the end so the clutch lever could fit flush against the shaft instead of 1/8th of an inch deeper. After I got the clutch lever installed I used the master cylinder rod and a level to figure out where to drill the hole. Once the hole was drilled I used the master cylinder to mark the holes for the mounting bracket. I will tell you this up front, I don't like the choice I made for my master cylinder. The bracket's clock is roughly 2 oclock which puts the top bolt into the bracket for the brakes. I would say if you want to move it over about an inch or two add a spacer to the clutch lever. I am also unsure whether this will interfere with a power brake booster since I have not done this conversion yet. I am pretty sure I will be OK. I welded studs to the firewall so I wouldn't have to mess with bolts and nuts later. Here are pictures of the clutch pedal slot, the clutch lever, the rod, and the master cylinder.

[jodydewey]

I tested the clutch pedal - all works as intended so far. I will know more once the clutch is hooked up. I don't anticipate any problems since it looks pretty straightforward. Next I will be fitting the transmission and engine back into the truck to see where the crossmember and hole for the shifter need to be. I have gotten a little sidetracked though with the immense level of corrosion on my radiator core support. As you can see, the only thing holding the core support to the truck was the fenders! It is supposed to be the other way around! Luckily I have a TIG and plenty of will to rebuild it. I am cheap so I don't want to spend $300 to get one from LMC. If I fail in my repair (not likely) I will buy it. I also have some repairs to do on the cab that I wasn't expecting.

[jodydewey]

Can someone go and measure from the firewall to the start of their power brake booster? I need to know if my new clutch master cylinder is going to be a problem. I am thinking now that it probably will be. The only way I can think of to get the master cylinder out of the way is to move it two inches or so to the left (on the firewall side). I can do this by making a spacer and welding it to the clutch lever. You can't just use a spacer between there because it will cause a bind in the linkage when you push the pedal. I am also thinking now that it was a mistake to weld in the bolts. If I am going to leave the master cylinder where it is I am going to drill the head off of the bolt that is in the brake bracket so it can be taken off to paint. Duh!!!!!!

[BUDDY]

Originally Posted by jodydewey

I installed the clutch pedal back into the truck with the updated clock. I found that I had to grind my weld a little better so it would fit. I also had to widen the bolt slot in the end so the clutch lever could fit flush against the shaft instead of 1/8th of an inch deeper. After I got the clutch lever installed I used the master cylinder rod and a level to figure out where to drill the hole. Once the hole was drilled I used the master cylinder to mark the holes for the mounting bracket. I will tell you this up front, I don't like the choice I made for my master cylinder. The bracket's clock is roughly 2 oclock which puts the top bolt into the bracket for the brakes. I would say if you want to move it over about an inch or two add a spacer to the clutch lever. I am also unsure whether this will interfere with a power brake booster since I have not done this conversion yet. I am pretty sure I will be OK. I welded studs to the firewall so I wouldn't have to mess with bolts and nuts later. Here are pictures of the clutch pedal slot, the clutch lever, the rod, and the master cylinder.

I think that you'll have a problem with the booster having the clutch there.

I would recommend, since you have the fab skills, to mount it on the other side of the master. I'm pretty sure you can get it over there above the junction block for the wiring, but you'd obviously have to "re-redo" the clutch linkage.

I'll take measurements & pictures of my master & booster when I get home tonight.

I love the project, & will be following closely as I want to put a NV4500 with hyd clutch in my blazer someday. Or maybe i'll just swap in the Duramax with it's 6-sp. Decisions, Decisions.....

Later,

Buddy

[jodydewey]

I had a friend go and measure his power brake booster to see if I was going to have any issues. His measured 7 5/8 from the top bolt to the top bolt and 8 inches at the bottom bolt to bottom bolt. The clutch master cylinder is 7 inches long. I think I lucked out there. If it doesn't work well I can always move it over a little more. The reason I didn't want to put it on the right side of the brake master cylinder is I believe I would have a problem with getting enough push on the clutch master cylinder without the linkage binding. The clutch pedal itself is on a much bigger arc than the small clutch lever is. I was able to control the up/down movement easier on a smaller arm.

[chevybill]

mdlackey, i am also using a nv3500 and my original 6 cyl crossmember could not be used. I have an auto crossmember which attaches to the rear part of the tranny just like an automatic. The original 6 crossmember does not drop low enough in the middle to this tranny with the original crossmember.

[7387chevys]

How much does the clutch linkage cost?What about an nv4500 would it be the same for the swap?
Shane

[watahyahknow]

Originally Posted by Palf70Step

Do you think you'll need to reinforce the firewall at all around the clutch MC? Once you get pressure int eh system, it would seem like that may put a lot of strain on the sheet metal.

BTW beautiful job on it. Looking forward to the finishing touches.

when i look at my european cars hydraulic cluch i see 2 band steel straps inside the cab running from the bolts of the clutchcylinder to the dash itself to prevent it from moving about .
that should be a pretty eazy solution on youre truck making straps that bolt from the cylinder to the mounting of the steeringcolumb or sumtin simulair

[mdlackey]

Chevybill, which auto x-member did you end up using? Do you have pics of the final install that you could share?

Jody, any new updates on your status?

Thanks,
Dave

[chevybill]

My crossmember came from www.performanceonline.com. I purchased tubular engine mounts and the crossmember at the same time.
I have no pics, truck is still in building stage and I am trying to figure out how I am going to make clutch linkage work.

[jodydewey]

I would love to see pictures of everyone elses conversion so I can see some stuff I haven't done yet. Pictures of interest would be the in the cab shots with the hole for the shifter measurement from the center front of the hump. I also agree about the crossmember. I will be using an automatic crossmember since that is what I have. I didn't even think about the height so thank you for that! I will check the angle with my handy dandy angle finder when I put in the tranny. Hopefully it will be 0 degrees. I also don't know about the driveshaft yet. My NV3500 came with the yoke of the old driveshaft and a piece of the old driveshaft. I haven't checked to see if the TH350 yoke and the NV3500 yoke are the same one. I will be putting the transmission/engine in this week for a test fitting. Hopefully all will go well. I will post some pictures.

[mdlackey]

Any of you, doing this NV3500 conversion, have plans for a speedo connection? Believe that the NV3500 has an electric speedo connection, while our original trannys had mechanical cable connection.

Would like to stay with a "mechanical" connection, since I have parts for a cruise setup, but may be easier to go to an electronic setup ...

Thoughts?

Dave

[jodydewey]

Originally Posted by 7387chevys

How much does the clutch linkage cost?What about an nv4500 would it be the same for the swap?
Shane

The clutch linkage cost me if I remember about $200 from LMC. I bought the hydraulic master, slave, and tubing all as a kit for a 1994 GMC 1500.


As for the NV4500 asked earlier, they are generally the same price I paid for in the junkyard and are more plentiful. If you are looking for an NV4500 look for a 4WD S10 with a 4.3L Chevy. It is the exact one you will need. The NV3500 is for 2WD, NV4500 for 4WD.

[BUDDY]

Originally Posted by jodydewey

If you are looking for an NV4500 look for a 4WD S10 with a 4.3L Chevy.

Where'd you get that information?

No S-10 ever came with the NV4500. The NV4500 is a HD (big) transmission for 3/4 & 1-ton applications. They are the transmissions that replaced the SM465 4-sp from the 3/4 & 1-ton trucks & added an OD gear. They were pu in behind the cummins diesel on dodge trucks & the big block & 6.5 TD in GM products. They can handle about 450 hp & 500 lb-ft in stock trim.

An NV3500 is a good candidate for this swap, but it's limit is about 250 hp/300 lb-ft. They did come in the S-10, but I'm not sure what years.

Also, the NV4500 has a separate bellhousing, whereas the NV3500 has an integral bellhousing.

HTH,

Buddy

[mdlackey]

Hey guys ...

Guess I'm the "guinea pig" ...

I did mount the master cylinder in front of the clutch pedal, instead of where the clutch rod penetrated the firewall. I removed the clutch pedal return spring, and used another bolt/spacer/nut setup to get the geometry close. TONS of leg effort to get about 1.5"-2" of pedal travel and hitting the end of the clutch travel ... nowhere close to the floorboard. See pics to see how it mounted up ... guess it was too easy to be the final setup. Moving the master cylinder higher on the firewall to get it closer to the pedals pivot point .. hence greater leverage and less leg effort will put it too close to the steering shaft, IMHO. Thoughts?

Was there a "clutch return spring" in the '90's NV3500 that made sure it pulled the clutch arm and throwout bearing off of the pressure plate? Noticed that the output shaft on the tranny is turning while in neutral, and stops when I depress the clutch. Would've been in the bellhousing assembly, if it were anywhere.

Currently, I have a single piece of 1/8" wall 1.5" square tubing that is holding the tranny in place. Have it drilled for the transmission mounting bolt. Will probably have another length of it welded to it for additional strength ... don't know if it is REALLY needed ... but just being cautious ... and will have 1/8" right angles welded to each end, then drilled so it can be mounted to the frame rails.

Anybody else have any updates and pics on their conversions?

Looking forward to hearing from all of you ...

Dave

[chevybill]

mdlackey, That looks really good, I have a later transmission that does not have the separate slave cylinder down on the bellhousing. I have to come up with a bracket that holds the actuating cylinder in the same location that you mounted your clutch master cylinder.

Have you driven your truck yet with this clutch setup?

As far as speedometer, I am using an electronic autometer speedo that is supposed to work with this tranny. Autometer 1405 designer black series.

[mdlackey]

Nope, haven't driven it, yet ... really concerned about what I'm going to have to do for the proper clutch articulation. Sounds great, thought, with just headers ...

Had driveshaft shortened, but it may not have been enough ... may need another 1/2" or so. Just too tight, when trying to mount back in to place. The "longer" one was the original, and it was shortened by about 6". The "shorter" one was from the '94 truck, and was TOO short. Plus, you'll see the difference in the end splines, where the intermediate shaft mates up with the rear driveshaft ... 10 spline versus ?? spline (27?) ...

Anybody figured out the "hump" over the tranny yet?

Dave