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I have searched the Fourm and can't find this, though I am sure it has been asked before....

I am thinking about a new trans for my thing (181) and need it to work well in the following conditions. My question is gearing, as my driving will be 80% on-road 20% off road (though I get kinda crazy off-road).

I will be stuffing a 2.0 914 type 4 in, so this will be to mate with that power plant.

What would be the best R&P and Final Drive would like to squeze the best highway performance without loosing to much off road performance.

With that in mind, what would be the maximum tire size, lets say 15X6 rears. Would like to run the tallest tire I can get away with. I will be running 2X3 (two inches longer, 3 inches wider) trailing arms. Also, will be running a 3" body lift.

So I guess I am looking for a high bred freeway flyer and a nice offroad trans?

Suggestions?

Randy

If you would like me to, I will send you an excel spread sheet that I built to calculate gear gatio for desired tire size, engine rpm, and road speed... Also I will send you a spredsheet of all the stock ratios. I am on the last step of building as near to a built proof thing trans axle as can be built. I suggest that you get your part through Weddle Engineering. They are the nicest folks and have a great stock of high performance parts. Somewhere on this forum is a detailed description of my trans. If needed I will dig out the details and repost them. K-mann

That would be great K-mann.

I will do a search and see if I can fond the older post

Randy

Randy I would say that if your 2L is stock then you should have at least a 4.86 R&P w no more than a 30 inch tire. If you have the engine built then probably a 4.56 will work. Its always a trade off when running street and off-road. If you want to get a taller tire then a 5.37 might be in order. You notice I think in terms of T-2 IRS ratios. My budget allows nothing else. You can easily spend more money on a transaxle than on an engine. Most aftermarket R&P sets are junk so check out well before putting money down.
http://www.geocities.com/lets_rock_1998/transtalk.html
This is some info from Eric Debord. Hes always willing to answer emails and questions regarding transtalk. I do not have links but Marc V. and Bruce are also both very Trans knowlegable. Best of luck. Bob Ingman

Are you thinking about a Type 1 trans, or a Type 2 trans? If it were me, I would only consider the Type 2 trans. Same coin to build, but you end up much stronger in the end with T2.

As for gearing, I would go w/ an 091 6 rib T2 trans which has 4.57 gear ratio. For good combo of hi-way and off road stay with stock 1st thru 4th. You can always change them later if they arent working how you want. Im in the same boat as you and considering a close 3rd(for off road), and a stock 4th(for hwy driving)

You think as I do Mattt. I am going to my third trans in the Thing. The 4.12 was not bad with the 1911cc engine but I did not like fourth gear. When I put a stock 1800 engine in I went with the 5-rib 4.86 and now that I have a 2056 with dual Dell 40s and WebCam I`m going with the 6-rib and the 4.57 for all round use.
Randy your cam will have a lot to do with your gearing and where your power band is. Best of luck. Bob Ingman

Bob, as you know I currently have a 5 rib bus trans(4.86 gear) in mine as well. When I switch over to Subaru power, Ill switch out to an 091 trans as well. Both for the additional strength, and the higher gearing.

The 4.86 is as close to stock gearing as you can get with a 29"-30" tire. If you set up and equation with tire size and gear ratio, you will see what I mean.

The 4.86 is a bit low for fwy driving, high RPMs being the outcome. Ive always wondered how the 75 bus with this trans didnt buzz to the moon-RPMs wise, when on the fwy. What I mean is that with a stock size tire, the high RPMs at fwy speed would even be worse than with my 29" tire. Maybe the T4 engine in the 75 bus is more suited to higher RPMs on fwy.

apple and oranges boyz ...\\

Issues

Trans 091 or 901 5 speed. depends on off-road or freeway flyer

Motor: (priceless) Subaru EJ25 DOHC...... 911 6H, pussy whipped T-4 2K cc hummer

Here inlies the issue.....

What are you trying to create and how much money or time do you have????/

I have a few solutions to all of the choices I have listed.



Each solution has it own advantages and it own list of issuse to resolve.

I just drop in to see what conditon my condition was in....\

K-mann

doesn't the '75 (one year only trans) have the same gearing as the 091 six rib, but had the 002 bellhousing that matched up with a type 1 motor?
Kurt

I built a gear ratio calculator to engineer trans gears to match ring gear and tire size that interface with resultant rpm and road speed. I will pmail the excel spread sheet to anyone who asks. K-mann

Kurt wrote:doesn't the '75 (one year only trans) have the same gearing as the 091 six rib, but had the 002 bellhousing that matched up with a type 1 motor?
Kurt

Nope the 75 bus trans has a unique final drive ratio-4.86. Its a one year only gearing option. Its a 002 trans. Its different from earlier 002 trans. It does have the early style bell housing that will work with the T1 starter. The input shaft is longer on the 75 trans because a 75 bus came with a T4.

68-74 002 bus trans 5.38 ratio
75 002 bus trans 4.86 ratio
76-79 091 bus trans 4.57 ratio

I think the 75 002 also has a mixture of 091 and early 002 gears. I think I remember some of the gears are wider like the 091. Not sure on this though.

Mattt you`re rirght about the 02s (72-73 1/2 3 rib). There were some 5 rib 02s w/5.37( 73 1/2-74) and some pryamid five rib in 75 with 4.86. By 76 we had the 091 6 rib. The pyramid case is sought after by rebuilders as the base for high performance transaxles. I`m using a T-1 starter on mine bit its the auto stick/thing variety without the pilot after the gear.
Last year Vince had a Thing transaxle freshly rebuilt and never installed that had a 4.37 R&P in it . It was available for $275 at that time. I do not know if Mike aquired it or not but if so would be a real good candidate for all round trans. Best of luck. Bob Ingman

Bob,
Are all 5 rib trannys the same, or is it just the '75 model that is sought after?
Kurt

Kurt it is the 75 5 rib PYRAMID that is particularly sought after. Best of luck. Bob Ingman

It would be nice to see pictures of all of these. I have never seen a Pyramid trans before...

Randy