Frknswt

I've got a '90 4runner w/3.0 motor and auto tranny. I just got the motor back in after a complete overhaul and it's running good. Since I bought the truck with a severely knocking motor I never had a chance to drive it. This is what I have discovered. Forward gears seem to shift fine but reverse will barely move the truck. If I'm on flat ground it will move okay but a slight grade will cause it to come to a hault. I can give it more gas but the motor just races. I don't know much about automatic transmissions but it feels like the clutch is slipping in reverse.
Does anyone know if there is a fix for this that doesn't involve a complete tranny overhaul?

Thanks,
T

bigarms23

tear into the tranny and make sure the clutch packs are in good shape

Frknswt

Can the clutch packs be accessed with the trans in the vehicle? Are hundreds of little pieces going to go flying if I take this thing apart?

Targetnut

This is usually a sign of low line pressure in the transmission. Reverse requires more pressure.

first, make sure the fluid level is OK, if that's not the problem, then remove the pan and replace the filter.

If this still does not fix it check line pressure in the trans.

More often than not if there is really a problem, it is because of leakage inside the trans and not becuse of worn clutches. However if it has been driven with low pressure then it is likely that the clutches will be worn as well from slipping.

SEAIRESCUE

A transmission shop can check all the previously suggested items plus they can drop the valve body and apply air pressure to each of the clutch pack pressure ports. With that done, they can feeler gage the slack in the packs. If the packs are good and the single band has not lost its lining, then the valve body needs to be evaluated. All of these evaluations will determine if the transmission needs to be removed.

MY $0.02

Frknswt

Thanks for all the replies.

I already changed the fluid and the filter. While the motor was out I pulled off the torque converter and let it drain out. I poured some new fluid directly in the torque converter and put it back on. Once the motor was back in I filled the trans. The total fill quantity was about 8 quarts and the level on the dipstick indicates it's correctly filled.
With that being said I guess it's down to low fluid pressure or worn clutch packs or both.
I'm fairly well mechanically inclined, is there a written procedure anywhere that I can follow to check the line pressure, feeler gauge the clutch packs as well as the pressure testing the different clutch pack ports? Or is all this best left to a certified transmission tech?

keithguts

I thought that the trans being empty took about 13-15 qts. Am I wrong?

Frknswt

I checked the manual again and it looks like the A340H takes 11.9 qts. I beleive mine is a A340F which has the manual 4WD shifter.

fireman1559

frknswt did u ever get your trans fixed i have the same problem. does your reverse work in 4lo mine does just not very fast and hills will stop me dead but it wont roll back down the hill its like its got power but not enough

abecedarian

don't 1st and R run the same clutch packs, but different planetaries? wouldn't it then be a band slippage issue?
I don't have a toy auto trans repair guide in front of me, but...

fireman1559

how would i take care of that problem?

mt_goat

Shortly after that thread he started this thread: https://www.yotatech.com/forums/f116...nykies-143196/

Then after that he gave up and bought my used A340H and swapped it in.

Gato Richy

did you towed your runner? reverse clutches always work, even in neutral. Clutches pack may born out.