View Full Version : largest tires on stock tranny & gears

03-21-2010, 10:24 AM
what's the largest tire to "safely" run on a stock 84 bII? i don't really want to have to replace a tranny anytime soon haha..

03-21-2010, 10:29 AM
What gears do you have in your axle? Your tranny wont mind what size tires you run as long as you have the right gears

03-21-2010, 10:38 AM
um, it's a d28. that's all i really know. i'm new to this stuff haha.

03-21-2010, 12:38 PM
there is a sticker inside the drivers door panel and that code will tell you which axle is in it. go to the tech library and it will help you translate it. also, there is (or should be) a tag on the rear axle pumpkin that will also have a code telling which gears are inside. but in any case, you should be fine with up to 235/75x15 tires at least, as long as you at least have the 3.45 or larger gears in it. larger tires would require lower (4.10/4.56/5.13) gears depending on tire size, lift, etc... imho.

03-21-2010, 12:44 PM
yea look on the door sticker there should be a code with ilke 42 or 44 etc, ill copy and paste the codes here from the tech library seems i have ntohing else to do lol

Code -------- Description -------Capacity ----------Ratio
42 ------------ open 7.5" --------- 2640 ---------------3.45
44 ------------ open 7.5" --------- 2640 - -------------3.73
45 ------------- open 7.5" -------- 2640 -------------- 4.10
D2 ------------ L/S 7.5" ----------- 2640 -------------- 3.45
D4 ------------ L/S 7.5" ----------- 2640 -------------- 3.73
D7 ------------ L/S 7.5" ----------- 2640 -------------- 4.10

now match your code up here and way to go you have your gear ratio.

i ran 235/75s with 3.73s and that had plenty of torque to bust shafts, if you have 3.45s id probably still rock some 235/75s but being easy on the gas.
I bust several shafts with 235s and 3.73s

03-21-2010, 01:47 PM
the sticker is missing haha.. i guess ill have to crawl under it tomorrow.. it's raining now

03-21-2010, 01:49 PM
i want to run 33x12.50s on 15x10 rims. i'm adding a leaf & spacers in front for an extra 2" plus i have a 3" body lift i'm going to add. what size gears would i need?

03-21-2010, 01:52 PM
well since you have an 84 BII, you have the D28 front end, which is horribly weak. you should get the Dana35 from an explorer or 90-97 ranger, and it depends what type of driving you will be doing. I would use 4.56s.

03-21-2010, 02:02 PM
i dont really intend on doing a bunch of off roading or anything. it's more for show. can i just switch the gears in the d28? or will i have to change to a d35?

03-21-2010, 02:03 PM
i have an 86 b2. 3.73 gears and i use to have the tk-5 tranny. it held up with 30x9.5's for years. but within the first two month's of my 33x12.5's i blew the tranny. swapped it for an m50d. and things are good. i have heard of ppl breaking things in the front and rear axle of our b2's on 33's. but so far i haven't had any problems. i'd still look into a 8.8 and d35 at least!

if you are gonna use it mildly i think you could get away with 33's on a stock b2, but no promises on how long it will last!

03-21-2010, 02:03 PM
yes you can use a D28. but a D35 is just a bolt in swap

03-21-2010, 02:16 PM
would i need to swap both the front & rear axles?

03-21-2010, 02:17 PM
not unles the d35 has different gear ration, both front and rear ratios must be the same or within a .04 difference

03-21-2010, 02:46 PM
You would be fine I think, I have run 31's for like 3 years now on 3.73's and I even ran 33's for a day. Not one sign of breakage or accelerated wear. For just show I think you would be fine with 31's, but I would recommend 4.10's if you go with them...

trail B2
03-21-2010, 04:09 PM
You can find 4.10 in the front and rear put some 10.5 31s on and it works pretty good.I put on 33's with 4.10 ratio and its perfect for me but thats with a 4.0 but now im on borrowed time with the d28.In order to put in the D35 sitting in my yard with 4.10,, an aussie ,set up kit ,its about $600 dollars witch I think your trying to avoid.To answer your question 31s with 4.10s a stock limited slip in the back a lock right in the front four wheels pretty good I surprised a lot of people with that set up.I'll bet you don't have 4.10s Allen D said they only came on automatics he really has this way of being right.

03-21-2010, 04:14 PM
i have 31x10.5 on my 88 ranger with 3.73 gears and i have had them for about 6 years and i haven't had any tranny problems

03-21-2010, 04:28 PM
all this talk about 31s lost me haha.. i want 33s

03-21-2010, 10:45 PM
so the rear end would be fine? or would i need to change anything in it as well?

03-22-2010, 07:46 PM
both front and rear axles have to have the same gears to use your 4 wheel drive without breaking the transfer case, drive shafts, etc.
i have the stock axles in my '83. d28 up front and ford 7.5 in the rear. i put in 4.56 gears and a detroit locker in the rear and i'm very happy with the performance running 31" tires. my tranny is a 5 spd from an '85 b2. i carry an extra 27 gal of gas in the bed tank and pull a small tent camper. i can easily use my after market cruise control!
just my $.02