64 Monza Transmission issue

All Models and Years
User avatar
Danny Joe
Posts: 203
Joined: Fri Nov 14, 2014 7:02 pm
Location: Toney, Al (just outside Huntsville)

Re: 64 Monza Transmission issue

Unread post by Danny Joe » Tue Feb 13, 2018 3:11 pm

Have you tested the transmission yet? You can disconnect it from the differential and test it with the input shaft to make sure the output shaft is working.
'64 Spyder Convertible
'63 Rampside (to be Rotisseried)
Toney, Alabama (just outside Huntsville)

66vairguy
Posts: 1485
Joined: Tue Dec 21, 2010 3:44 pm

Re: 64 Monza Transmission issue

Unread post by 66vairguy » Tue Feb 13, 2018 3:35 pm

A picture is worth a thousand words, but here goes -- The input shaft goes from the clutch through the hollow differential ring and pinion shaft into the transmission hollow main shaft and into the clutch gear that turns the counter shaft. Whenever you select a gear the input shaft is coupled to the main shaft via the gears. The hollow main shaft goes into the differential hollow ring and pinion shaft and engages inner splines in that hollow ring and pinion shaft. THOSE SPLINE ARE NOTORIOUS for wearing out. Usually the transmission output shaft will slip inside the ring and pinion shaft when the splines fail. ALTHOUGH usually there is some interference, but I suppose a complete shear is possible.

The other thing that comes to mind is either the clutch gear, counter gear, or main shaft may have a problem. I've also seen a few transmissions where the shifter forks were not properly engaged with the gears.

This is why I stay in good graces with "Dan the Gear Man" in the SCC Los Angeles CA club.

Ron64Convertible
Posts: 23
Joined: Thu Feb 08, 2018 8:14 am
Location: Woodbridge, VA

Re: 64 Monza Transmission issue

Unread post by Ron64Convertible » Tue Feb 13, 2018 5:45 pm

I have not separated the transmission from the differential yet. It looks like the transmission is not transferring power to the differential, maybe the splines are stripped. I will separate the two tomorrow and see if I can tell. I took a video of me shifting the gears and then turning the input shaft in each gear, but couldn't figure out how to attach it. I only know the basics about transmissions. There is one gear in the back of the case below the main forward gears that doe not turn when I place it in gear, is this the reverse gear?

Wagon Master
Posts: 223
Joined: Thu Jul 28, 2011 6:36 pm

Re: 64 Monza Transmission issue

Unread post by Wagon Master » Wed Feb 14, 2018 6:45 am

That is technically called the reverse idler but yes, it moves between the mainshaft and counter gear to cause reverse rotation.

Current bets are,
1. Worn pinion internal splines.
2. Wrong transmission input shaft. Should have 14 splines on small end not 12 if indeed using a 64 trans.
Although either of these would still allow you to shift into reverse with engine running. So something is also hanging up the input shaft.

Ron64Convertible
Posts: 23
Joined: Thu Feb 08, 2018 8:14 am
Location: Woodbridge, VA

Re: 64 Monza Transmission issue

Unread post by Ron64Convertible » Wed Feb 14, 2018 7:25 am

The input shaft has 10 splines at the clutch and 14 on the small end. They appear to be in good condition. I believe the transmission is from a 64 however the differential may be from a 63. I should have them separated later today. Due to the amount of grime and dirt caked on them when I got the car I assume it had been like this for many years.

Ron64Convertible
Posts: 23
Joined: Thu Feb 08, 2018 8:14 am
Location: Woodbridge, VA

Re: 64 Monza Transmission issue

Unread post by Ron64Convertible » Wed Feb 14, 2018 10:51 am

Well, I guess I found the problem. The output shaft, from the transmission, is broken off flush with the transmission case and in about four pieces inside the pinion shaft. I think I can replace the pinion gear and shaft, doesn't look too difficult, but not sure about the output shaft. Any special tools needed to replace the shaft? What would normally cause this shaft to break, the gears move freely in both the trans & diff? Could this be caused by someone driving it too hard?

66vairguy
Posts: 1485
Joined: Tue Dec 21, 2010 3:44 pm

Re: 64 Monza Transmission issue

Unread post by 66vairguy » Wed Feb 14, 2018 12:29 pm

Now you know why it was "parked".

Just a wild guess, but since the differential was replaced with a 63 unit I suspect a major ring and pinion failure from the original (64) differential might have caused the transmission output shaft (main shaft) to have been fractured and later it broke.

You are at a crossroads here, find another used replacement and hope for the best (getting scarce now) or have a "qualified" Corvair transmission person inspect and rebuild the transmisson. While you're at it I'd get the differencial inspected/rebuilt and find a proper 64 case since a fully functioning leaf spring (64 only) rear suspension is considered an asset that will increase the vehicles value.

It comes done to how nice the car is and if you want (or can) spend the money on it.

If it was a solid Western car I'd spend the money, if it has rust issues it may not be worth putting money into.

BTW - the pinion gear can be pressed off and onto a replacement pinon shaft (done it many times) - NEVER MIX RING AND PINION GEARS. Always keep as a set, especially good used ones.

Good luck.

Ron64Convertible
Posts: 23
Joined: Thu Feb 08, 2018 8:14 am
Location: Woodbridge, VA

Re: 64 Monza Transmission issue

Unread post by Ron64Convertible » Wed Feb 14, 2018 1:06 pm

I bought the car for a project 9 months ago and have done lots of work already, about 80% restored. This is going to put me over my budget, but will probably continue. I am looking around for some options now. I really do appreciate all the help I have received from Corvair Forum. Thanks for all the help. I'll let you know how as project proceeds.

Ron64Convertible
Posts: 23
Joined: Thu Feb 08, 2018 8:14 am
Location: Woodbridge, VA

Re: 64 Monza Transmission issue

Unread post by Ron64Convertible » Mon Feb 19, 2018 7:48 am

I am weighing my options to either buy a rebuilt transmission or replace the broken main output shaft in the one I have. I've never rebuilt a trans before and not sure if I will need special tools. After looking over some videos I think I can disassemble it, but not sure if I will need to have a press to remove gears/bearings etc.. It looks like I have two issues. 1 (broken trans output shaft) and 2 ( the clutch doesn't disengage. I installed a new clutch/pressure plate/throw-out bearing) the new clutch hardware was for a 64 however I think I have a 63 differential in my 64 with the 64 recessed flywheel. I did not replace the 1" fork pivot stud, could this be the issue with the clutch not disengaging? I checked the linkage and clutch, which looks to be installed correctly, not backwards. The differential looks to be in good shape other than no mounting bracket for the transverse spring. Are the after market brackets for the spring (for 63 models) still available?

User avatar
bbodie52
Corvair of the Month
Corvair of the Month
Posts: 7608
Joined: Mon Aug 06, 2012 12:33 pm
Location: Lake Chatuge Hayesville, NC
Contact:

Re: 64 Monza Transmission issue

Unread post by bbodie52 » Mon Feb 19, 2018 9:09 am

The attached illustrated guide may give you some idea of the work involved. You might contact a source like The corvair Ranch to discss your needs and get a price for a used serviceable transmission. They have a large inventory of Corvair parts cars, trucks, and vans and should be knowledgeable about the components you need.

:link: http://www.corvairranch.com/
Image

1079 Bon-Ox Road, ​Gettysburg, ​PA. 17325 USA
​Phone: 717-624-2805
fax us by the same number... ask us to hook up the machine
​Email: findit@theranch.today
Our hours are Monday thru Friday 9 to 5, Saturday 9 to 12
or contact us for an appointment.


:chevy:
Attachments
Corvair - Overhauling the 1961 4-speed Transmission.pdf
Corvair - Overhauling the 1961 4-speed Transmission
(3.48 MiB) Downloaded 1 time
1961 Chevrolet Corvair Shop Manual - Section 6d - Manual 4-Speed Transmission.pdf
1961 Chevrolet Corvair Shop Manual - Section 6d - Manual 4-Speed Transmission
(627.42 KiB) Not downloaded yet
1964 Supplement - Chevrolet Corvair Shop Manual - Section 6d - Manual 3 and 4-Speed Transmission.pdf
1964 Supplement - Chevrolet Corvair Shop Manual - Section 6d - Manual 3 and 4-Speed Transmission
(194.42 KiB) Not downloaded yet
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

66vairguy
Posts: 1485
Joined: Tue Dec 21, 2010 3:44 pm

Re: 64 Monza Transmission issue

Unread post by 66vairguy » Mon Feb 19, 2018 9:15 am

Ron - You could dismantle the transmission, but assembly requires some knowledge for good results. A fellow in our Los Angeles, CA club has been rebuilding Corvair transmissions for decades. Just about every year changes were made, some major, some minor. Unlike the later 66-69 units the earlier transmissions require a knowledge of how to use correct spacers for best performance. The 64 is considered the best shifting unit of the bunch if rebuilt correctly.

Yes Clark's sells the leaf spring bracket if you have the correct differential case.

I'd suggest getting on the Corvair Center forum where you'll find more resources. If you weren't on the other side of the country you could have Dan the Gear Man in L.A. fix you trans and he has a spare 64 differential case, but shipping would be expensive.

Hopefully you can find a resource closer to you. - Good luck.
Last edited by 66vairguy on Mon Feb 19, 2018 9:55 am, edited 1 time in total.

Ron64Convertible
Posts: 23
Joined: Thu Feb 08, 2018 8:14 am
Location: Woodbridge, VA

Re: 64 Monza Transmission issue

Unread post by Ron64Convertible » Mon Feb 19, 2018 9:25 am

I was wondering if I got a new 64 differential case if the gears could be transferred from my old one or did the gears also change from 63-64? The bracket I was referring to was the one listed in the add earlier in the posts. Looks like an after market adapter to put a transverse spring on an earlier model differential. Thanks for the info, I will try to find a good mechanic in this area.

66vairguy
Posts: 1485
Joined: Tue Dec 21, 2010 3:44 pm

Re: 64 Monza Transmission issue

Unread post by 66vairguy » Mon Feb 19, 2018 10:04 am

Ron64Convertible wrote:
Mon Feb 19, 2018 9:25 am
I was wondering if I got a new 64 differential case if the gears could be transferred from my old one or did the gears also change from 63-64? The bracket I was referring to was the one listed in the add earlier in the posts. Looks like an after market adapter to put a transverse spring on an earlier model differential. Thanks for the info, I will try to find a good mechanic in this area.
There were some changes made in the EM cars, but you should have no problems moving the 63 parts to a 64 case. One critical area is the pinion shaft bearings. The first to fail and I never re-use them. Setting up ring and pinion clearance is basic, but you need a slip shaft to select the shims. If the original pinion shaft and gear are used then USUALLY the fit is fine. If you install a new pinion shaft (press pinion gear on and off) then a shim fit needs to be checked. BTW - that shim sticks to either the pinion gear or bearing. I've seen more than one were the shim stuck to the bearing and was thrown out by accident!!

Oh - the instructions and pattern illustrations in the shop manual for setting up ring and pinon clearance ARE REVERSED. The Corvair Center forum has the corrections for the manual.

Ron64Convertible
Posts: 23
Joined: Thu Feb 08, 2018 8:14 am
Location: Woodbridge, VA

Re: 64 Monza Transmission issue

Unread post by Ron64Convertible » Mon Feb 19, 2018 11:01 am

Thanks for the additional info.

66vairguy
Posts: 1485
Joined: Tue Dec 21, 2010 3:44 pm

Re: 64 Monza Transmission issue

Unread post by 66vairguy » Wed Feb 21, 2018 10:23 am

If you do decide to rebuild the differential into the correct case yourself - you'll need an inch pound wrench to set the pinion shaft bearing pre-load - it's critical!! You can find inch pound wrenches on-line, they are made to assembly high-end bicycles.

joelsplace
Posts: 23
Joined: Wed Oct 13, 2010 12:51 pm

Re: 64 Monza Transmission issue

Unread post by joelsplace » Thu Feb 22, 2018 5:00 pm

Don't forget that the '64 differential has a dipstick. You can get the tube, fitting and firewall grommet from Clark's but not the dipstick.
The clutch may not have been disengaging because of all the broken parts dragging on the shaft. Also make sure the clutch fork is installed on the pivot ball correctly. The ball goes against the fork and the spring clip behind the shoulder of the ball. In other words the ball goes between the fork and clip.
I would replace the shaft. '64-'65 transmissions are getting harder to find and the parts aren't getting more plentiful. I didn't catch what is wrong with the pinion shaft. Are you just assuming it's bad because of the broken main shaft?
Clark's lists a used main shaft CU907 for $48.00

Post Reply

Return to “Ask your Mechanical Questions here”