I'm building a custom box for my 4-runner - an R150F (excellent shape, 20k miles and clean!!!) with a 4.31 first from a 151 trans. (marginal condition) With the 150's low range of 2.58 or 2.67 and my 5.29 gears on 33" tires, I can get an acceptable crawl ratio for around here with parts I ALREADY HAVE.

Questions - Has anyone done this swap? The internals are supposed to be the same. However the 150 I have has a longer case in front of the intermediate plate than does the 151 - that would lead me to believe things inside are not quite the same, though i suppose the gears could be. Does anyone know if there was a design change during the 88 - 95 150 build run? I noticed on Marlin's page he lists the 150 from 88 - 91 for a rebuild with this 4.31 gear - but nothing after... Suppose I have a 92 or later 150. Any input appreciated.

Brian

I would call Marlin at Marlin Crawler (http://www.marlincrawler.com) he knows Toyata Trannies inside and out and am sure he would give you the 411 :usa:

I'm no expert, but I believe the internals are all the same and what you are doing will work. Even for the 95-up R150's AFAIK, although the input shaft is supposedly a slightly different length on those...

I'd ask Marlin about that 88-91 cutoff. You could even try their new BBS.

The guy you really need to talk to is "JD Ozrunner" (James Douglas) on 4x4wire, not sure if he goes by the same screen name here, but he's on here too somewhere. He's definitely a Toy Tranny guru. :)

G'Day Eric :)

Brian

Sorry mate you have to either swap in all the R151 internals or use the R150 as is.

Except for overdrive the corresponding gears for all ratios, eg 1st 2nd etc are machined on a mainshaft so its not possible to just change one gear as then it will not mesh correctly with its mating machined gear.

This pic was to show the difference in size between a W series and R series shafts etc but you can see what I mean. The gears are part of the shaft and not removeable. First gear is the small one on the far right.

The R151 uses 32/11 gears and the R150 31/12 so if you put a R151 32 gear on the mainshaft it will not mesh with the 12 tooth gear on the layshaft UNLESS you had this gear recut to 11 teeth.

http://home.access1.com.au/~ozrunner/graphics/Gears1.jpg

I wouldn't mind swapping all the internals - but it looks as though they will not fit the 150 case - it is longer than the 151 by a good 1" (25mm) from intermediate plate to the front input shaft beaing. This must be the longer input shaft that has been mentioned(?).

Brian

Ahhhh... problem solved - thanks for the pic, JD. The tranny I have is a W series - sold to me as R151, It came with a 4-Runner I bought. Never inspected it until now.

B

Originally posted by Bjowett
I can get an acceptable crawl ratio for around here with parts I ALREADY HAVE.

Don't kid yourself. The difference between the 3.95? 1st of the R150 and the 4.31 of the R151 isn't going to do much with a 2.57 V6 tcase. Double the tcase then you'll notice. You'll still be burning up clutches. :nuke: Keep the R151 and run the duals.

The 150 has a 3.83 which would give me 52 - 1 ratio, the 4.31 would bring it to 58.

The point is moot now, anyway. I don't have an R151.

Thanks for the input!!

Brian

that sucks, but since it is in very good shape you could sell it for the price of a used 151