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Thanks for the info, It will come in handy, BUT, in reading the info out there, I find there are two different types of Trans. used; with some disagreement as to what was used.
(1) Muncie 4 spd. M-21 (68-mid 74)
(2) Warner 4 spd. (mid 74-81) T-10 close ratio.
coded: S6 wide Ratio 1st gear 2.85:1
ZU Wide Ratio 1st gear 2.64:1
ZW Close Ratio 1st gear 2.43:1
are found on left side on top rear of case.
also (74-81) painted 2 digit code Left side below side cover
HS = 2.64:1 Close Ratio
HW = 2.43:1 Wide Ratio
Considering this is a 78 year lets go with the Warner. M21
One other thing to look at the side cove; Muncie used 7 bolts, Warner 9. (it's 9 bolts)
and I can easily look at the side cover area. But do not recall any numbers there.
Last edited by Douglas Brown; Mar 25, 2018 at 02:16 PM.
After looking under the car, It is a Borge Warner, 9 bolt cover.
Casting numbers are 3-15-78
1304 065 903
W.G. DIV.
FpC1 W (this W stamped into casting)
Last edited by Douglas Brown; Mar 25, 2018 at 02:51 PM.
Is your transmission original? check on the driver's side.
Top vertical is your partial vin and below that would be trans info. In this case.
W (warner), D (April)21(day of month), 8 (1978) and 2 (2nd shift).
The Muncie in 78 was delegated to the L48. Rare is a 3.36 with a L82 and if correct it is usually associated with a wide ratio car from my readings. With a L82, 4spd, standard equipment was a 3.70.
Is your transmission original? check on the driver's side.
Top vertical is your partial vin and below that would be trans info. In this case.
W (warner), D (April)21(day of month), 8 (1978) and 2 (2nd shift).
The Muncie in 78 was delegated to the L48. Rare is a 3.36 with a L82
and if correct it is usually associated with a wide ratio car from my readings. With a L82, 4spd, standard equipment was a 3.70.
good information.
here is what I can see:
and from driver side
NO NUMBERS looks like they were taken off, possible a rebuild.?
I went over the paper work I have on this car. I know it was purchased from AZ, taken to Wyoming, where a 350/396 crate motor was installed, then clutch replaced.
Last edited by Douglas Brown; Mar 26, 2018 at 11:22 AM.
Hey Thanks for the info, it will come in handy as learn more about the transmission in the this car.
as a side note:The Cruise control still did not work, got a new lever, it is made poorly and uses thin tubing that bent when trying to install, due to dia. of new lever being larger than orig. just enough to not slid in as it should have. I took it apart and tried to make a new one out of the old lever, any all it does is accelerate will not hold. began removing it.
I think you will find that you will have to go more than 1 tooth. You have over a 10 % error and going from 22 to 23 teeth is only going to make just under a 5% correction.
I think you will find that you will have to go more than 1 tooth. You have over a 10 % error and going from 22 to 23 teeth is only going to make just under a 5% correction.
Considering I was under misinformation and lack of knowledge about the Transmission and rear axel when I started, I can live with that.
I do know that the rear axel is a 3.70:1, it is a BorgWarner trans, T10, M20, M21 model Alum case made 3/15/1978 The Drive Gear is an 8 Tooth Large Blue gear # GM 3708144 and it had a sliver/gray 22 tooth Driven Gear # 3987922.
IF the NEW 23 tooth gear still runs too slow I can add a 24, but first lets see what this does.
IF I reduce speedometer by 5 miles per hr. that will leave me showing faster by 3 mph which is not bad.
AND I am running P255/60 R15 rev. per mile 787.18, Stock is P225/60 R15 rev. per mile 745.85
SO I am picking up 3.5 mph in tire size alone.
IF I were to go back to stock tires then I would have to add the 24 tooth gear??? to make up for the other 5% loss.???
Thanks for the input, it all helps.
DB
Last edited by Douglas Brown; Mar 27, 2018 at 02:46 PM.
Well the 23 tooth gear arrived and I got it installed.
On paper it looks like this:
3:70:1 r-axel
BorgWarner Trans 1.00:1 4th gear
Drive gear 8 tooth
Driven gear 23 tooth
tires P255/60 R15 878.18 Rev. / mile
IF I had stock tires P225/60 R15 the Speedometer would run 10 miles faster than car; BUT with P255/60 R15 (adds 3.5 mph), I run 6.5 mph faster, the speedo will read 6o and I am doing 52.5 mph. With the 23 tooth driven gear, it slows down the speedo by 5 mph, NOW the speedo reads 60 I am now 58.5 mph. OR 1.5 mph off/slower than the speedometer at 60 MPH.
GOOD
Last edited by Douglas Brown; Apr 7, 2018 at 08:03 PM.
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78 C3 Trans. Driven gears
