r151f gearbox probs on a 105 series

[sjp]

does anyone have any gearbox problems with their 105 or 78(i think)series cruisers with the above gearbox,mine(2003 model,diesel) makes a kind of meshing sound ,sort of as if starved for oil in 3rd and 4th when its cold and even after its warmed up,happens mainly when iam coasting with just enough pressure on the pedal to maintain the speed,once i put the foot down it stops, toyo says its just the natural lashing sound of the box and is a bit noisy because of the lack of insulation under the vinyl?? but will take the box apart under warrenty but says he doesent know what hes looking for(i dont want them to say that they found nothing wrong and lose my chance of getting the problem fixed under warrenty which will run out very shortly.

[dow50r]

Start saving now...they usually go in third...to fix it properly, put a 80 series gearbox and transfer behind the motor...the r series box (hilux, prado, supra) is just too weak.
Andrew

[BOB_1]

Dunno if its the same but most of the 105s we have at work do a bearing sort of noise while not under load. They do it from new and Toyota don't really seem to care when its bought up with them. Since they are work cars, we don't chase it much since they don't seem to blow in the 60000 kays we have them.

[slosh]

Start saving now...they usually go in third...to fix it properly, put a 80 series gearbox and transfer behind the motor...the r series box (hilux, prado, supra) is just too weak.
Andrew

Just in case anyone is considering upgrading to a real man's box, I have 80 series auto and transfer that I will swap for r series box and transfer from 79/ 105.

[sjp]

bob that sounds like it ,i'll see if they will change the bearings ,
dow brothers third gear went ,fixed under warrenty,thats wat the mines etc do i guess keep them until the warrenty runs out and then getrid of them

[smithie]

I've got an R151 in my 1990 PZJ70 SWB. I lost 5th gear (another common problem) back on the labour day long weekend.. and also have what i believe to be bearing noise in 3rd - 4th when coasting. It doesnt surprise me as i reckon its a consequence of the 5th gear going.. there is fine mettallic flakes through the oil.
But all that aside, Its held together for 4 months, with a few hardcore 4wd trips in there and i'm running 35's so i cant complain to much

I'd drop a little oil and check for fine silver flakes (bearings) or fine gold flakes (synchros) or metallic chunks (get it to toyota quick) especially while you have warranty.

goes to show that the r151f is 'relatively' strong despites its problems. however i'll be changing to an 80 series box very soon.

hope some of that helps.
dan

[treebruiser]

200,000 kays and a bit of nois in the box, nothing failed there yet, although the transfer gave up the ghost at about 160. Turbo'd and locked so cops lots of abuse. Used for towing on regular occasions.

[ferrit]

our prado is slowly dying with the same box...

Syncro assembly between 3-4th is weak, toyota took too much metal out of them when they were building them to make the gear shift action lighter, and only splined it on the 3rd- so there arent splines the whole way round. End of the splines on each 1/3 become a stress point, and it cracks the whole assembly from inside to outside- you get stuck in 3rd or 4th and you CANT change it out- its a gearbox out job to un-jam it.

Other problem is the spline on the output shaft is weak- thats where your backlash it- its the spline slowly chewing itself to bits- yota used too big splines on them, so they cant spread the torque properly... you eventually shear the splines clean off and loose ALL drive.

Fix for this is to rebuild the output shaft with a fine tooth spline on it and change the input shaft on the transfer case to suit, and replace the synro assembly with a new one thats got ALL the steel left in it and is splined the whole way round on the inside.


The guy who rebuild our prados transfer case and front diff has done about 30 of these boxes for Western mining corp- they come in blown, and he rebuilds them and rectifies the problems while hes there... we were quoted about $1200 to do it IF we got it to him before it blows up... if it looses the Syncro- thats another $500 to fix the damage, if it does the shaft, thats another $400, and if both blow, you wont get out of it with much chang for $2500 for a full rebuild as it damages the input shaft on the transfer case too!

Needless to say, our prado doesnt get driven much any more till we can find the money to rebuild the POS box!

[sjp]

thanks ferrit ,i'll copy that reply and give it to the toyo mech,getting a bit pissed that the vehicle comes with these inherent problems (front diffs,gearboxes ,no towing grunt)so guess what i was looking at getting --yea a prado, wonder if the new ones have the same box,you'd think they would have done something there to handle the torque of the new motor

[ferrit]

i HEARD that they changed the output splines and the syncro on the later year ones, but that could just be heresay...

I'll give you the contact details for the guy who does the work for western mining and also worked on our truck.

4 x 4 Transmissions
9 Katrina Ave Windsor Gardens SA 5087
ph: (08) 8266 6288