Driving a truck with mismatched ratios

[chvyfan]

Alright, theoretical situation.

Front has 3.42 and rear has 3.08. In normal 2 wheel drive with front driveshaft removed with u-joint still attached on the axle as to keep the pinion up out of the diff. I see no problem with this as a temporary set up for maybe 30 minutes max of driving cumulitivly. Now my knowledge only beginning to grow as far as gears and transfer cases are concerned and figured it couldn't hurt to check.

but I'll most likely be having matched ratios anyways. just as back up knowledge

[Yoda]

do you have locking hubs? if so just disengage them to the internals dont spin and you should be good. im not sure if leaving the u-joint attached will keep the pinion out of the diff or not.

[yotacowboy]

u-joint still attached on the axle as to keep the pinion up out of the diff.

not following here... why is the u-joint still attached?


but the general consensus on miss-matched diff ratio's is no greater than 10% with big tires (larger circumference). on smaller tires (stock, 29, 31), i'd say 5% would be okay.

as long as the transfer case is in 2wd hi range, regardless of whether you have locking hubs or not, the truck doesn't care what ratio's are in the axles.

[CRAWL3R TJ]

I don't believe I would go through the trouble of remving the u-joint from the driveshaft just to leave it installed on the front pinion yoke in hope of keeping the pinion out of the diff. The yoke will do a good enough job on its own, after all it does fine while the driveshaft is connected.

Like said above, if you have manual hubs, just unlock them. If you have auto-hubs or unit bearings that are locked all of the time do not shift into 4wd. If it is a part-time 4wd system then I would remove the driveshaft.

[tsmall07]

I don't understand what the hell you guys are talking about with the "u joint keeping the pinion up out of the diff". The u joint has absolutely nothing to do with the pinion staying in place. If you take the u joint off, the pinion will not fall into the diff housing.

[jonesy]

Alright, theoretical situation.

Front has 3.42 and rear has 3.08. In normal 2 wheel drive with front driveshaft removed with u-joint still attached on the axle as to keep the pinion up out of the diff. I see no problem with this as a temporary set up for maybe 30 minutes max of driving cumulitivly. Now my knowledge only beginning to grow as far as gears and transfer cases are concerned and figured it couldn't hurt to check.

but I'll most likely be having matched ratios anyways. just as back up knowledge

so there is no front driveshaft?

run it forever.

i have 307s out back and 538s up front ... and have had it like that for a month with no front driveshaft, no problems at all so far.

[tsmall07]

I drove my '96 with mismatched gears for almost a year. There will be no issues.

[CRAWL3R TJ]

I don't understand what the hell you guys are talking about with the "u joint keeping the pinion up out of the diff". The u joint has absolutely nothing to do with the pinion staying in place. If you take the u joint off, the pinion will not fall into the diff housing.

Reread my post about how I didn't understand why the OP wanted to go through all of the trouble to remove a u-joint from the driveshaft just to keep the pinion from falling into the diff when the yoke is still there to perform that job.

[Slinkey]

as long as the transfer case is in 2wd hi range, regardless of whether you have locking hubs or not, the truck doesn't care what ratio's are in the axles.

X2

Like said above, if you have manual hubs, just unlock them. If you have auto-hubs or unit bearings that are locked all of the time do not shift into 4wd. If it is a part-time 4wd system then I would remove the driveshaft.

I assume you mean if it is a full-time 4wd system then you need to pull the driveshaft. If it is part-time, which most 4x4's are, there is no need to pull the shaft, just don't engage four wheel drive and the gear ratio in the front axle won't be relevant.

[chvyfan]

the reason I was thinking to remove the driveshaft is cause it still rotates in from the front axle while driving, I had thought possibly that since it goes into the tcase this might present a problem, but I'm guessing now that without 4wheel drive engaged it is idealy "disengaged" completely and won't cause any grinding or what not

[CRAWL3R TJ]

I assume you mean if it is a full-time 4wd system then you need to pull the driveshaft. If it is part-time, which most 4x4's are, there is no need to pull the shaft, just don't engage four wheel drive and the gear ratio in the front axle won't be relevant.

You are correct. Guess I was typing too fast or not typing fast enough to keep up with my thoughts.

[chvyfan]

I assume you mean if it is a full-time 4wd system then you need to pull the driveshaft. If it is part-time, which most 4x4's are, there is no need to pull the shaft, just don't engage four wheel drive and the gear ratio in the front axle won't be relevant.

You are correct. Guess I was typing too fast or not typing fast enough to keep up with my thoughts.

yea, I just need to learn to read better

[Slinkey]

the reason I was thinking to remove the driveshaft is cause it still rotates in from the front axle while driving, I had thought possibly that since it goes into the tcase this might present a problem, but I'm guessing now that without 4wheel drive engaged it is idealy "disengaged" completely and won't cause any grinding or what not

As long as you are in 2WD, the front output of the transfer case is effectively in a neutral, free spinning state. As with my Jeep with unit bearings, they front axle shaft(s) and the front driveshaft are always spinning, but they are not connected to the rear driveline while in 2wd because of the transfer case. It is definitely not a bad idea to pull the driveshaft, it's just not necessary.