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17 replies to this topic

#1 WJM

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Posted 01 November 2003 - 06:36 AM

Ok, this transmission in my GL-10...its not an XT6 transmission. I appears EXACTLY identicle to one tho...the only difference is that it came with the XT/L series crossmember mounts on it.

So...here is the deal...it actually came out of a *unknown year* XT Turbo, a rare one with the Spyder intake. So this IS a FT4WD transmission, i know this, the center diff locks, and there is always some kind of power going to the rear. I really think its an 87...since the place wrote 87 on the trans...

So here is the QUESTION...what is the final drive? 3.70, or 3.90????????????

It seems to have the same RPM at 60 as the RX in HI, 3k. The RX is 3.70.
thats a 400 rpm difference from the 2wd XT turbo trans thats 3.70.
I've got a 3.90 rear diff installed, cuz thats what the specs are on the XT6, 3.90. But if this is a 3.70 trans, I need to know before I drive it even more! Or even think about locking that diff....

To be 3.90, or not to be 3.90? That is the question....

#2 TomRhere

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Posted 01 November 2003 - 07:16 AM

Oneway to check the tranny/front diff/rear diff: Pull your spark plugs, raise all the wheels of the ground, mark tires and body with chalk, tape, whatever, place tranny in gear lock the center diff, turn engine over by hand and check your alignment marks. All should lign back up, or atleast I'm thinking so.

#3 Meeky Moose

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Posted 01 November 2003 - 08:01 AM

i believe toms test would work.. if front diff and rear diff are different ratios one would turn faster than the other making the marks be out of alignment on a revolution or 2 of all 4 tires..

white chalk on the tires would work for the marks and a 8' 2x4 to get them even me thinks would work also..

#4 MilesFox

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Posted 01 November 2003 - 09:17 AM

the xt 6 in butler has the ft4wd single range. by buddy said it has a 3.9 gear! a 3.9 gear dhould do 60 at 3500, while a 3.7 will do 65

#5 WJM

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Posted 01 November 2003 - 10:27 AM

alrighty...thanks all! Anyone got any more info?

#6 WJM

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Posted 01 November 2003 - 06:08 PM

well, i locked the diff and marked the tires on loose gravel, and did a small stright line...the rear tires lag behind. I need a 3.70. I guess I'll go get one monday! I was gonna autocross sunday...But I'll wait until nov 29th and maybe do it with the RX instead.

#7 c150L

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Posted 01 November 2003 - 08:30 PM

I checked today, my 89 XT-6 is tacking 2800@60mph, 3100@ 65mph and 3500rpms brings 75mph. Everything is stock. What gears do I have?

FT4wd, air susp, 5 speed, locking center diff.

#8 WJM

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Posted 02 November 2003 - 08:41 AM

damn, thats the same as what I am getting on the RX and GL-10. The GL-10 is supposed to have 3.70, and the RX definatly has 3.70.

XT6 is supposed to have 3.90 according to all the specs I've seen.

I think the internal gearing is different between the RX/XT/XT6 FT4WD trans, so that same RPM is met at same speeds, but with a different final drive.

#9 calebz

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Posted 02 November 2003 - 09:03 AM

From all that I have seen, XT6 FT4WD is 3.9. XT4 FT4WD is 3.7

#10 WJM

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Posted 02 November 2003 - 12:42 PM

Ok, I'll be getting a 3.70 for sure now.

#11 c150L

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Posted 02 November 2003 - 04:59 PM

Aren't the final gears in manual transmissions direct drive? Input shaft and output shaft turn same speed? I know it was/is on all the old American 3 and 4 speed manual transmissions I have tore apart and rebuilt.

#12 WJM

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Posted 02 November 2003 - 05:52 PM

no. the FT4WD trans have an open center diff. The regular 4wd are direct drive.

#13 bushbasher

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Posted 02 November 2003 - 06:15 PM

he means that top gear on old american transmissions were 1:1, straight through with no gear ratio, whereas with our sube transmissions 5th (or 4th) involves gears, and isn't 1:1.

#14 c150L

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Posted 02 November 2003 - 07:47 PM

Yup. The transmissions I've tore apart, the final gear was not actually a gear, the splined slider in the transmissions just locked the input shaft directly tothe output shafts. Direct drive in that last gear.

Where would one find the individual gear ratios in the different transmissions in our Subes. Appears to me, the front and rear differential ratios may or may not the whole kabootle when one is deciding on which drive line components to use when modding and/or converting their stock set up.

#15 GeneralDisorder

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Posted 02 November 2003 - 08:14 PM

courtesy of McBrat - from a post a long time ago, and on the old board. It's still around here somewhere, but it's so messed up from the conversion, it's nearly impossible to decipher (I fixed it up, so we can read it):


At least for the 1982's from the Factory Service Manual:

1600 transmission:

Gear--4 spd/5 spd
1------3.666/3.666
2------2.157/2.157
3------1.266/1.266
4------0.885/0.885
5----------0.725
Final 3.70

1800 transmission:

Gear--4 spd----5 spd all-----5 spd wg-----4wd Brat----4wd Brat D/R
1------3.307----3.307--------3.307--------3.636--------3.636
2------1.950----1.950--------1.950--------1.950--------1.950
3------1.344----1.266--------1.344--------1.266--------1.266
4------0.942----0.885--------0.942--------0.885--------0.885
5---------------0.725--------0.725
Final 3.70 except Brat which was 3.899 front 3.90 rear

Obviously, these aren't the numbers you are specifically looking for, but it shows that final drive IS NOT 1:1. It also shows how much variation there is - even on a single type of transmission from a single year......

GD

#16 WJM

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Posted 02 November 2003 - 09:37 PM

much info....cool beans

#17 AKIRA

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Posted 02 November 2003 - 09:54 PM

Transmission gear ratios

4spd d/r Gears
1 - 3.636
2 - 1.950
3 - 1.193 (81-82 is 3 - 1.266)
4 - 0.769 (81-82 is 4 - 0.885)
R - 3.583
H – 1:1
L/R - 1.462:1
Final - 3.9

5spd d/r Gears
1 - 3.545
2 - 1.947
3 - 1.366
4 - 0.972
5 - 0.871
R -? 3.416
L/R - 1.592
Final - 3.9

RX Gears
1 - 3.545
2 - 2.110
3 - 1.448
4 - 1.088
5 - 0.871
R -? 3.416
L/R - 1.196
Final 3.7

1600 Gears/4 spd/5 spd
1------3.666/3.666
2------2.157/2.157
3------1.266/1.266
4------0.885/0.885
5----------0.725
Final 3.70

1800 Gears
Gear--4spd-----5spd all-----5spd wg-----4wdBrat----BratD/R
1------3.307----3.307--------3.307--------3.636--------3.636
2------1.950----1.950--------1.950--------1.950--------1.950
3------1.344----1.266--------1.344--------1.266--------1.266
4------0.942----0.885--------0.942--------0.885--------0.885
5----------------0.725--------0.725
Final 3.70 except Brat which was 3.899 front 3.90 rear

#18 c150L

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Posted 03 November 2003 - 11:43 PM

Awsome info! I would have thought there would have been 1:1 in there somewhere.




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