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Guest Message by DevFuse

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help needed - 5 spd d/r swap into a Brat

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12 replies to this topic

#1 Guest_IsraBrat_*

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Posted 06 August 2003 - 07:30 AM

Hi guys I just talk with a mechanic about a 5 spd d/r tranny swap into my 94 brat.
He told me some changes need to be done:
1.he told me that the 5 spd is actually shorter then the 4 spd one and so the driveshaft is either to be changed or to make the current one longer.
2.the final ratio of my brat is 3.7,some sources say the 5spd is 3.9 and some say it's 3.7, which one is the right ratio?

I know alot of you guys over the board done this swap but the problem is that I live in Israel and no one over here knows s#%t about this mods.
So any of you guys who done this please post your answers.

thank you for your time

Roi - Roiziss@hotmail.co.il

#2 Guest_GeneralDisorder_*

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Posted 06 August 2003 - 10:00 AM

Oh yeah - your the one with the 94 Brat right? 3.7 eh? I think all the manual tranny ones over here were 3.9. I do believe (I'm no expert on newer soobs tho) that there was a 3.7 D/R 5 spd in something? Someone will know.... Or you could just get a 3.9 rear end off something else. The driveshaft off the 5 spd car (two peice) would work, or you could get it lengthened. Problem with that is since it's longer, it will stick down further under the car. With the two peice, you will have to weld up the center carrier to the Brat. Also - the tranny tunnel is a little tight for the 5 spd, and the linkage is different. There is a guy on the board that makes a kit for the linkage and clearance problem, other wise, you can use the boots and consoles from the 5 spd car, and do some banging / cutting of the tranny tunnel. Certainly possible tho.


#3 Guest_edrach_*

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Posted 06 August 2003 - 05:25 PM

3.9 diffs are about $30 at the local Pull a Part. Changing the rear diff is probably easier than finding a 3.7 d/r transmission. Jerry (bratsrus1) did the conversion on my '84 Brat and later replaced the two piece drive shaft with a custom one piece. The conversion is worth every penny of cost and effort. Car runs a little bit quieter with the one-piece drive shaft. I'd suggest Jerry's conversion kit since it leaves all the interior linkage and such looking stock. Also, the '88 d/r gearbox seems to work the best in the conversion. I don't know why, but it seems to be the gearbox of choice.

#4 Guest_IsraBrat_*

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Posted 07 August 2003 - 05:35 AM

Thanks for your answers guys.
but the more important question is HOW can I tell the ratio of the 5 spd tranny I wanna buy so I'll know if I do need to change the rear diff.

#5 Guest_edrach_*

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Posted 07 August 2003 - 06:24 AM

Most 5 speed d/r trannys are 3.900 ratio. To check, set it into 1st gear and turn the input shaft while observing the output shaft. After 3.9 turns, the output shafts should turn once; if slightly more, then it's a 3.700 gearbox. Another way is to check the label for the ratio of the rear diff of the donor car; should be the same ratio as the transmission diff.

#6 Guest_LostWater_*

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Posted 07 August 2003 - 06:40 AM

I must have missed this discussion in the past. How is this done? Does this avoid having weld/bolt a carrier bearing holder underneath an ea-81 car?

This may be what I need to do since if I want to do this conversion on my hatch, it requires a driveshaft shortening anyways.

Thanks and Kindest Regards,

Christiansburg, VA

#7 Guest_edrach_*

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Posted 07 August 2003 - 08:51 AM

The one piece driveshaft eliminates the center bearing. Also, talk to your driveshaft maker about putting zirk fittings on the u-joints.

#8 Guest_ShawnW_*

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Posted 07 August 2003 - 09:22 AM

I think you will need a longer driveshaft.....

Amazing as it sounds, but the 5spd dual range is shorter than the 4spd dual range.

#9 Guest_IsraBrat_*

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Posted 07 August 2003 - 11:14 AM

Edrach thanks for a great tip I'll try this trick tommorow and post the result.

BTW: if any one have any more tips about the swap I'll be happy to hear about it

#10 Guest_subyaddict_*

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Posted 07 August 2003 - 12:48 PM

I just did this to my 1983 ea81 wagon. I used the carrier bearing setup, because it was cheaper that having a driveline custom made. The two-piece driveline from the any ea82 with a mnual is just the right distance. I have a wagon but I beleive the brat has the same measurements. If you are going to go off-roading and you have a lift and such, I would suggest the custom one-piece for durability and strength.
I have rallied the heck out of mine with no problems.
Also the tranny I just happened to end up with was a 3.7 d/r.
I think it came from a loyale because it has the loyale d/r handle. I don't know for sure though. If you want some pictures of how I did it, I can do that.
Good luck man. In my opinion it is worth all the trouble, because 5th gear makes me very happy.
When my car was a 4sp it topped out at about 70 mph at about 5k revs, now it will tack out the speedo (85+ mph).:D
1983 gl wagon d/r 5sp R-LSD, R-Discs, top speed approx.95 mph, Can do perfect cookies all day
Japanese auto motor(higher cam lift)
Going to spfi later this year

#11 Guest_edrach_*

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Posted 07 August 2003 - 03:42 PM

I agree with Nathan that the swap is worth all the trouble. Before the gap between 3 and 4th was immense; going up a long hill on the interstate meant 5000 rpm in 3rd and not enough rpm in 4th to maintain speed. With the 5 speed transmission, the engine will always be within the powerband of 2000 to 3500 rpm regardless of speed--there's always a comfortable gear available.

#12 Guest_IsraBrat_*

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Posted 07 August 2003 - 03:50 PM

Thanks allot guys it sure did helped me to go for the swap ( 700$ over here).
any way I'll have to go for the custom driveshaft because 4wd soobi stuff is hard to get in Israel (unlike the 2wd soobies).
I just hope it's a 3.7 because it's really hard to get rear diff's over here

#13 Guest_edrach_*

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Posted 07 August 2003 - 07:23 PM

If you're desparate for a 3.7 diff, it should be shippable from the states; it seems you're willing to spend the bucks for the shipping and a 3.7 rearend is about $30 here from the local Pull a Part.

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