How easy is it to swap an 88 Pontiac Fierro MT1 isuzu differential into a 96 cavalier isuzu transmission? I am looking to change the final drive ratio in my cavalier which is 3.58 to the ratio that is in the Fierro which is 3.35.
How easy is it to swap an 88 Pontiac Fierro MT1 isuzu differential into a 96 cavalier isuzu transmission? I am looking to change the final drive ratio in my cavalier which is 3.58 to the ratio that is in the Fierro which is 3.35.
Anyone? Help would be greatly appreciated! I'm just trying to get my car to have the gear ratio's I want.
The whole carrier assembly *should* drop right in. Remember though, you need to have the pinion pulled off your output shaft, and the new one pressed back on.
Ok. I know what the inside of the transmission looks like and the whole differential assembly but what exactly is the pinion that needs to be pulled off the output shaft? Is that the shaft in the middle of the primary shaft and the differential? Have any diagrams or anything? Thanks!
You need to replace both of these pieces to swap FDRs, which entails pressing the bearings and gears off of the output shaft. You will need at least an arbor press to do it, and a bearing and seal kit would be a good idea. This is actually a 3.58 set from a Storm.
Also, why do you want to go that low? Your car will be slow as sin.
Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
Thanks! And that is the secondary shaft correct? The middle shaft between the differential and primary. On a cavalier the bottom gear is a lot bigger than that. It is really small on the primary shaft.
Also, I want to do this because it is the only gear ratio that will work where all i have to do is switch tires to run at two different oval tracks.
Thanks!
It is possible I may be able to get the correct gear ratio with all of the fierro gears. Would a fierro transmission bolt up to a cavalier?..
Yes it's the secondary shaft. Both of those gear look exactly the same as every isuzu gear set Ive seen, they just have different tooth counts. So I don't know what you're talking about saying the cav "bottom" gear is bigger than what is in the picture.
Wouldn't you want to run a higher FDR so you can accelerate faster?
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Yes, sorry you are right about the small gear. My bad.
And as for the FDR. I want to run in the same gear and not have to shift all the way down the straight. I need to be running around a total of 7.5. For example in the stock transmission the FDR is 3.58 x 2nd gear which is 2.18 = 7.8. And then i can change my tire sizes anywhere from 70 inches in circumferance to 84 inches in circumferance to acccomplish different ratios. I need to be able to have the pull of the corner but not hit the rev limiter to early. If I have a FDR of 3.35 in the same second gear which is 2.18, I have a total of 7.3. this means I will be slower off the corner but be able to go further. Now on the track where I hit the revlimiter too early I will have more to be able to make it down the track with the biggest tires I have. And the track where I run normally at I can just go down in tire size and still hit the revlimiter in the same spot.
Why not just change 2nd gear to the storm/impulse 2.04?
"The FACTS are always subject to CHANGE once the TRUTH is applied"
"In the entire history of man the only stupid questions are the ones that don't get asked"
I didn't actually know which one would be easier. After knowing what all goes into changing the FDR, that sounds easier. Just have to press the gear off the primary shaft and put that one in? And the fierro has that same 2nd gear of 2.04.
You'll just have to find a trans. with that 2nd gear ratio. I've not been able to find an isuzu trans. around here with a 3.58 FDR (pretty sure they all have a 2.04 2nd. ). I've got a 3.83 FDR trans. here with a 2.15 2nd. I had to buy the 3.58 gear and shaft from Transporter that's in those pictures in order to do my trans.
"The FACTS are always subject to CHANGE once the TRUTH is applied"
"In the entire history of man the only stupid questions are the ones that don't get asked"
You also have to change two gears (one on both the primary and secondary shaft) if you want to swap 2nd gear, but I would say it would be easier than an FDR swap.
Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
Transporter7220 wrote:You also have to change two gears (one on both the primary and secondary shaft) if you want to swap 2nd gear, but I would say it would be easier than an FDR swap.
^ This ^
"The FACTS are always subject to CHANGE once the TRUTH is applied"
"In the entire history of man the only stupid questions are the ones that don't get asked"
Ok. So how can you tell what 2nd gear it has? Not all 90-93 geo storms have a 2nd gear of 2.04?
john317(AKA Gary the Old guy) wrote:You'll just have to find a trans. with that 2nd gear ratio. I've not been able to find an isuzu trans. around here with a 3.58 FDR (pretty sure they all have a 2.04 2nd. ). I've got a 3.83 FDR trans. here with a 2.15 2nd. I had to buy the 3.58 gear and shaft from Transporter that's in those pictures in order to do my trans.
I'm running that 2.04 second gear, only because I wanted to swap to one piece synchros though. But I've gotten to like it, especially after turning my torque management off. It's nice to be able to make it to 60 with just two gears.
You'll have to be careful which tranny you get (1 piece or 3 piece synchro version) if you're going to look for the 2.04 second, the synchro race is a different diameter between the two, and it's impossible to get apart and pressed back on without warping the race. The guy at drivetrain.com told me the only way to know which one you got was to open it up and look.
One piece on the right, three piece on the left...
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Joe Shmidt wrote:Ok. So how can you tell what 2nd gear it has? Not all 90-93 geo storms have a 2nd gear of 2.04?
Buy a tranny, take it apart, count the teeth.
I suppose you could pop it in second at the junkyard, and spin the input by hand, and then keep track of the number of input revolutions it took to spin the diff once. That would be pretty tricky though.
Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
So do all stock geo storm transmissions have the 2.04 2nd gear? I can use my FDR from my cavalier that is the 3.58 and just change the 2 gears for second on my primary and secondary shafts? Also which synchro race do I want? The one or three piece? They will both work for the cavalier but one is impossible to press back on?
Thank you guys! Sorry if I ask too many questions!
tim, didnt you need to machine some material off something to get that setup to work?
If it takes forever.... I will die trying. Underdog Racing
I had to machine the reverse gear, but I still don't know why I needed to, and what had changed that made me need to.
Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
Tim, did you check your output shaft and diff. shims? I borrowed a set of Kent-Moore J-33373 Shim Selectors from a GM Tech buddy of mine. I just my own set off e-bay for $35 shipped.
All these transmissions I've torn apart have different thickness shims in both places.
Jim, It's kind of hit and miss what year and style car are have which gear ratios. Here's a site that might help
http://www.robietherobot.com/storm/geo_storm_spec.htm
"The FACTS are always subject to CHANGE once the TRUTH is applied"
"In the entire history of man the only stupid questions are the ones that don't get asked"
We spent some time messing with shims, everything was measuring up to be in the same place but we just couldn't figure it out. I think I only took about .050" off of the back of reverse, it was juuuuuuust barely scuffing.
But you're probably right, one of the shims probably needed to be about .010-.020 thicker. It's working fine now though.
Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
