VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 1936 Pick-Up info

Hello Everyone,
I met an older gentleman last night at a local car meet with a 1936 Chevrolet pick-up and offered to help him with some lighting issues. (The truck was restored in 2003.)
He also mentioned slight grinding when trying to shift the trans. He has 1 inch of free play at the pedal and the idle appears to be around 400 rpm but I haven't verified that yet. This problem is also happening during all up shifts and down shifts. I asked about gear lube and he has 90w in the trans and 90w in the rear.
(He has a manual but it doesn't show what the rpm at idle should be, any info about the tune-up would be great.)
As far as the clutch issue, I suggested the possibility of the engine, bell housing and transmission mounts might all have to be replaced. (this is info I have read about in '37-'42 forum)
I would really like to help this gentleman, so any info would be great.

Dave,
You didn't mention if the transmission in the 36 pickup is a 3-speed or a 4-speed. If it's a 3-speed, 2nd and 3rd gear are synchromesh and you should be able to shift from 2nd to 3rd or from 3rd to 2nd without grinding. If it's grinding when shifting, it's possible the synchros are badly worn. If the transmission is a 4-speed, there are no synchros in it, and it must be double-clutched to shift without grinding.

With the 4-speed, 1st gear is not generally used for normal, on-road driving. Starts are made with 2nd gear. When shifting up to 3rd gear, as you pass through neutral, with your foot off the gas, let the clutch out, then depress it and move the shifter on into 3rd gear. Use the same procedure for shifting from 3rd gear to 4th gear. You can't be in a hurry when you do this--no speed shifts--especially once the transmission is thoroughly warmed up and the oil is thinned out. Shifting from 2nd to 3rd when starting out on an up hill is difficult to do without grinding, because you want to get into 3rd before the truck loses forward momentum, but if you try to shift too quickly, the gears will grind.

When shifting down, as from 4th to 3rd, or 3rd to 2nd, when you pass through neutral, you have to rev the engine when you let out the clutch so that the transmission input shaft speed matches the output shaft speed. To put it another way, the engine must be revved (in neutral with the clutch pedal out--engaged) so that it is running at the approximate rpm that it would be running if you were driving in the gear that you're shifting to. To complete a bumpless shift, say from 4th to 3rd, when you rev the motor as you pass through neutral, hold the gas pedal to keep the engine revving as you let out the clutch in 3rd gear. If you've matched the engine revs correctly, the truck speed will remain the same, but you'll now be in 3rd instead of 4th, ready to accelerate or decelerate, as needed. This takes a little more practice than up-shifting, but if your throttle linkage is not sloppy and you can hear the engine, it's pretty easy to get the hang of it.

The shop manual for my 37 Chev pickup says to adjust the carburetor idle stop screw so the engine idles at 400 rpm. While the 37 is a slightly different motor, I suspect 400 rpm would be a good idle speed for the 36 as well.

Mark

An excellent explanation of shifting gears in an older Chevrolet. Good job.

Hello Mark,

Thank you for your info. Unfortunately I did not ask if it was a 3 speed or 4 speed. What I can tell you is the owner has had it for along time and from our conversations, I think the shifting problem is relatively new. The pick-up is smaller than my '37 4door MD so I assumed it was a 3 speed. I will be getting together with the owner this weekend to help make a few repairs.
I'll let you know how I make out. Thank you again.

Hello Everyone,

I checked out the '36 Pick-up and the trans is a (3) speed. I found the idle to be 300 rpm's and I adjusted the idle and fuel mixture to achieve 400 rpm. I also checked the clutch adjustment and found it has (1) inch of travel at the pedal.

The trans has trouble engaging without grinding going into reverse and low which sounds like clutch or clutch adjustment. Did find the trans is leaking between the bell housing and transmission but the clutch doesn't chatter so I'm not sure about gear lube on the disk.

I asked in a earlier post about using 85w-140 (he has 90w in there now) in the trans but I think it may have been over looked and I would like your take on making this change in an attempt to cure his engagement problem. (he did say he plans to pull the trans this winter to fix the leaks.)

Thank you for any help you all can provide.

Picking the idle speed up to specs will help. I nearly always adjust the clutch to allow 1/16" freeplay at the outer end of the throw out arm with the pedal held at the top of its travel and throw out bearing against the clutch.I have found this method works on 80% of mechanical linkage and cable type clutches.

Others on this forum have stated that the 90w is a bit thin for those old gearboxes so until they are proved wrong I will follow their advice.

Tony

Dave,
I use 85w-140 in my 37 1/2 ton and my 40 1/2 ton, both with three-speed transmissions, and have had no transmission problems in the dead of winter or in the 100+ heat of summer.

I always shift into neutral at stoplights and let out the clutch pedal to save wear-and-tear on the throwout bearing and the crankshaft thrust bearing. However, especially when the transmission is hot, when shifting back into first gear when the light turns green, the gears will grind unless you first shift momentarily to 2nd or 3rd, then into first. By doing this, the 2nd or 3rd gear synchros will stop the gears from spinning and allow a shift into first (or reverse) without grinding. In fact, you don't even have to shove the shift lever all the way into 2nd or 3rd--you just need to push it far enough to engage the syncro drum and ring, which you can feel by slight resistance in the shift lever.

You should have your friend check the oil level in the transmission. If it's way low, it could affect the shifting. Besides external oil leaks, the transmission oil can leak through the propeller shaft seal at the front end of the torque tube and run back into the rear end. This is a fairly common problem, especially on higher mileage vehicles. There's no external evidence of this, so you need to check your transmission oil level on a regular basis. If the level continues to drop after repeated refilling, with no obvious external oil leaks, then it's fairly certain the oil is leaking out the propeller shaft seal. Further evidence of this condition is that the oil level in the rear end will rise, and if it gets high enough, it can result in leakage at the rear axle seals, which will show up as radial lines of oil on the inside wall of the rear tires if the car is driven regularly, or as a single rivulet of oil leaking down the inside wall of the rear tires at the bottom if the car remains parked most of the time.

Mark

Hi Mark,

I thought I would see the gentleman who owns the '36 Pick-up at tonights local meet but he didn't show. I'm hoping to see him tomorrow night at a larger cruise at the local VIP parts store. I printed the posts from this site for him to read.

Thank you all for your help.

Hello Mark,

The owner of the pick-up tried your suggestion and was mildly surprised. He is no longer embarrassed when leaving cruise night.

As for the gear lube, he plans to make that change when he fixes the leak at the front of the trans.

Thanks for the info.

Dave,

I'm glad the info helped your friend in driving his pickup.
Perhaps now he won't have to endure some smartass kid yelling at him, "Hey Pops, grind a pound for me while your at it!"

Mark