Transaxle identy

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olemanjohn

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My 1986 Fiero SE transaxle has this tag "6CDC GM CANADA FJNN
"24-C2 *616 CDC JFJNN
"HYDRA MAX
"8652568 CFD 17

My question is: Is this the same transaxle as the Chevy 200 R?
The reason that I ask is my rpm at 60 mph is 3800rpm. I would like to lower this to 2800 rpm if possible at 60 mph.
 
https://en.wikipedia.org/wiki/Pontiac_Fiero




All automatic-equipped Fieros were equipped with the three-speed TH-125 with torque converter lockup. Automatic transmission final drive ratios:

1984–1986: 3.18 (RPO "F75")
1987–1988: 3.33 (RPO "GX3")
TH-125 Gear Ratios
1st Gear: 2.84
2nd Gear: 1.60
3rd Gear: 1.00
Reverse: 2.067


Manual transmission gear ratios[edit]
Year Style Code Axle 1st 2nd 3rd 4th 5th rev.
1984 econo 4-speed MY8 3.32 3.69 1.95 1.24 0.73 — 3.42
1984 perf 4-speed M19 4.10 3.53 1.95 1.24 0.81 — 3.42
1985 V6/4-speed M17 3.65 3.31 1.95 1.24 0.81 — 3.42
1985 I4/5-speed MT2 3.35 3.73 2.04 1.45 1.03 0.74 3.50
1986 V6 4-speed M17 3.65 3.31 1.95 1.24 0.81 — 3.42
1986 V6 5-speed MG2 3.61 3.50 2.05 1.38 0.94 0.72 3.41
1988 I4/5-speed MT2 3.35 3.73 2.04 1.45 1.03 0.74 3.50
1988 V6/5-speed MG2 3.61 3.50 2.05 1.38 0.94 0.72 3.41
 
there is something wrong with either your speedometer, tachometer, or transmission. The Fiero should have a 25" diameter tire and with an automatic transmission a 3.18:1 rear ratio. Based on those numbers at 60 mph the tachometer should read 2,564.
1. Have you verified your vehicle speed using GPS?
2. Have you verified your tachometer accuracy by attaching a handheld device with RPM capabilities?
3. If both the speedometer and tachometer accuracy are verified as being correct it would appear your transmission is not up shifting into 3rd gear.
 
Transaxle identity

It sounds like you have hit on the problem. I have suspected that the tranny is not up shifting to third gear. I will check it out and get back to you.
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Transaxle identity

I've checked the shifting of the tranny and it is up shifting into 3rd gear. I suspect the RPMs to be correct, but I will check with a manual vibrating tool.

Prior to my acquirement of this Fiero; it was used to street race. Is it possible that the Tranny could have been altered? If so, how and can it be corrected?
 
recommend you read this link and in particular check if the throttle cable is correctly adjusted. The transmission uses a chain with different sprockets that effect the final drive ratio. You would have to find out from the previous owner what if anything was done to the transmission.
http://www.fiero.nl/ogre/th125.htm
 
this link may help you show you what the tag should read. I am thinking like you think that someone swapped the transmission to something different and perhaps modified it as well.
I would just buy a replacement transmission- transaxle for it.

http://www.gafiero.org/bbs/index.php?topic=1065.0
 
Transaxle identity

If the tranny is chain driven and someone changed a gear ratio would they only change one sprocket or both the drive and driven? Can you give me a method to check this out.
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