STANDARD
TRANSMISSION RESTORATION 1957 TO 1981
STANDARD REBUILDS
Rebuilding of a Chevrolet
Corvette Muncie or T-10 transmission involves about the same amount of work to
accomplish.
The three-speed gearbox is
easier to work on. The very early T-10
transmissions are a little harder to find parts for, especially if you are
trying to match numbers.
A lot of new reproduction
parts are being made for all years of the Muncie transmissions, except for
exactly original cases and tail housings.
However, you are now able to buy a real nice reproduction Muncie
aluminum main case replacement it looks slightly different from the
original.
So, all that said, basic
rebuild costs of a standard Corvette four speed transmission for both T10 and
Muncie are about the same assuming you are using quality parts and all that is
required is a standard rebuild. Serious internal damage runs the costs up
accordingly.
PARTS $___________
LABOR
$___________
ADDITIONAL
CONSIDERATIONS
Now, the above parts and
labor sounds pretty reasonable for a standard transmission rebuild. Once in a great while a transmission will be
in such excellent condition all that is required are the standard replacement
parts and a standard rebuild.
However, if even one gear,
such as reverse, is worn out the cost of a rebuild starts to climb. Many times if the transmission is leaking
gear oil from the front it can mean the counter gear shaft is loose in the main
case. The main case can usually be re-bushed with a steel insert or the case
replaced with a reproduction unit. (Non-numbers match case).
Another common problem is
worn out syncro hub assemblies. A real
bad find is when the transmission gears are losing their case hardening and a
whole new set of gears are required.
The only way a transmission
can be properly evaluated is to break it down, clean it up and very carefully
inspect all the individual parts. Then
make the proper decisions on what is required.
If a transmission is in very poor condition there are three
alternatives.
My first choice would be to
go with good quality new reproduction unit.
A second choice would be to use good used parts, when they can be
located.
A third choice, if the
transmission is totally worn out, would be to locate another used transmission.
The third choice is not and easy one, because either we would have tear the
used transmission down to check it out or take a chance and install it as
is.
The above is not meant to
scare the customer, but we just never know what to expect when purchasing a
used transmission. The above can be
especially true when you consider that many of the transmissions we rebuild are
over thirty five years old and can have as much as 200,000 to 300,000 miles on
them.
I often wonder how many
more times a Muncie transmission can be rebuilt. In the last thirty years I have seen a few come back about every
ten years and they are still going strong.
Just remember “rebuilt”
really means “repaired” and does not mean the transmission is brand new again.
After so many miles, for example, the case hardening on the gears will wear
through. Click here for a blow up of the Muncie transmission taken right from
the General Motors illustration book.
PARTS AS REQUIRED
LABOR $_________
SHIFT LINKAGE
While rebuilding the
transmission, freshening up the shift linkage at the same time should also be
considered. The shift linkage is a
fairly simple device, however, in most cases it is probably one of the most
over looked parts on the Corvette.
Unfortunately the shift
linkage is open to the elements. That
is, all the levers and its shift body are not equipped with any kind of cover
to protect it from the weather. The
Corvette shift linkage was greased, installed and adjusted at the factory.
Over the years the linkage
collects a lot of road film and grit, which causes wear and sloppy
adjustment. In order to rebuild the
shift linkage it is first disassembled, cleaned and inspected. The shift linkage parts, levers, rods, body,
clips, t-handle and other required parts are still available either from G.M.
or as reproduction parts from 3rd part vendors.
It’s entirely possible to
build a whole new assembly from new/repro parts if required. In most cases the shift linkage can be
rebuilt with a minimum of required parts.
Frequently the shift lever handle will require a weld to tighten it back
up to original. Once the shift linkage
is rebuilt, it is simply reinstalled in the car and properly adjusted.
PARTS $_______
LABOR $_______
TRANSMISSION AND LINKAGE
RESTORATION
As with all the other parts
on a Corvette the difference between restoring a transmission and it’s shift
linkage lies only in the cost of the time required to do the job.
For example, to make the
transmission case and tail housing look original it requires more time for
clean up and preparation than just hot tanking the parts. Depending on how original the customer wants
his transmission to look, the case might require a special cleaning or tumbling
process to achieve a very original look.
NCRS RESTORATION
NCRS restorations require
special consideration. Cost depends on what kind of condition the case and
housing are in. Also, there are main
case and side cover bolts which will require plating if they are original. Main case, side cover and tail housing
numbers must be checked to make sure they match the Corvette.
If the part numbers don’t
match, correct parts must be located to put the Corvette back to original
condition. The shift linkage must look
original and the shift lever stick will probably need to be plated, especially
if it has been re-welded. The levers,
rods and nuts must look and be original also.
TIME AND MATERIAL AS REQUIRED