Switching to 4wd while driving

By accident ,I was driving about 40 mph and switched to 4wd. Can that damage the trans?

 

Nope. Shift on the fly 4wd has been a thing for many decades. Visor label or owners manual will describe the proper operation of the 4wd system in your truck. Up to 55mph or so it is safe to engage the 4wd system. 4hi that is. You will have to come to a stop to engage the 4Lo. You can drive in 4hi at higher speeds than 55mph, but you cannot (should not) change from 4hi to 2hi or 2hi to 4hi above 55mph.

 

As long as you shifted it back and didn't make any sharp turns on the pavement, and you don't hear/feel any binding or noises, you should be all good.

 

The truck will start beeping and refuse to shift if you're outside the allowable parameters too

 

Do yourself a favor and read through the manual.

https://www.toyota.com/owners/warranty-owners-manuals/

 

Manual states that 62mph is the limit for switching from 2WD to 4H or 4H to 2WD. My experience is the alarm will sound and prevent switching from 2WD to 4H if over 62 but system will let you switch from 4H to 2WD if over 62.

 

Thanks , you make me feel much better. I know they say you can switch to 4 wheel drive driving but I never did it. It seems wrong to me, but what do I know. It’s all good now