dumb auto question
#1
dumb auto question
I have a really basic question. I've never wheeled an auto before and would like to know if this is normal or not.
My truck is an 86 4runner with the auto. Should it have any compression braking in 4 low. I lost my brakes going down hill and almost lost the truck. I know there is no direct connection like on my manuals, but it seems there should be some fluid resistance. I had absolutely none.
I'm also having a problem going up hill. Level ground it works great. As soon as you put it on an angle, I loose all power. The engine spins and spins, but its is not even trying to turn the drive shafts. Fluid is full.
My truck is an 86 4runner with the auto. Should it have any compression braking in 4 low. I lost my brakes going down hill and almost lost the truck. I know there is no direct connection like on my manuals, but it seems there should be some fluid resistance. I had absolutely none.
I'm also having a problem going up hill. Level ground it works great. As soon as you put it on an angle, I loose all power. The engine spins and spins, but its is not even trying to turn the drive shafts. Fluid is full.
#3
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Had this same problem in a bronco i owned a while back. Only owned it for about 3 days before i jumped it and rolled a few times. So i never figured out what the issue was.
#4
Sounds like we have two separate issues at hand.
Intermittent brake system and Automatic Transmission faults.
Brake system fluid level correct..?
Verify no brake system lines/hoses/hydraulics are leaking brake fluid and or damaged.
Verify linings and friction surfaces are in good condition.
Brake pedal assembly damaged..?
Brake booster assembly fault..?
Any other symptoms with automatic transmission assembly..?
Does it pull well during all other ranges..?
The automatic transmission assembly may be "tired" or worn out internaly.
Poor tourqe converter operation..?
Fluid level incorrect..?
Incorrect fluid type..?
Fluid filter..?
Engine throttle body assembly fault..?
Intermittent brake system and Automatic Transmission faults.
Brake system fluid level correct..?
Verify no brake system lines/hoses/hydraulics are leaking brake fluid and or damaged.
Verify linings and friction surfaces are in good condition.
Brake pedal assembly damaged..?
Brake booster assembly fault..?
Any other symptoms with automatic transmission assembly..?
Does it pull well during all other ranges..?
The automatic transmission assembly may be "tired" or worn out internaly.
Poor tourqe converter operation..?
Fluid level incorrect..?
Incorrect fluid type..?
Fluid filter..?
Engine throttle body assembly fault..?
#5
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An auto will compression brake to an extent. Will it slow you down to idle? No. How fast were you going on 4lo? Did you have the transmission locked in 1st? Did it actually hold 1st?
#7
Sounds like we have two separate issues at hand.
Intermittent brake system and Automatic Transmission faults.
Brake system fluid level correct..?
Verify no brake system lines/hoses/hydraulics are leaking brake fluid and or damaged.
Verify linings and friction surfaces are in good condition.
Brake pedal assembly damaged..?
Brake booster assembly fault..?
Any other symptoms with automatic transmission assembly..?
Does it pull well during all other ranges..?
The automatic transmission assembly may be "tired" or worn out internaly.
Poor tourqe converter operation..?
Fluid level incorrect..?
Incorrect fluid type..?
Fluid filter..?
Engine throttle body assembly fault..?
Intermittent brake system and Automatic Transmission faults.
Brake system fluid level correct..?
Verify no brake system lines/hoses/hydraulics are leaking brake fluid and or damaged.
Verify linings and friction surfaces are in good condition.
Brake pedal assembly damaged..?
Brake booster assembly fault..?
Any other symptoms with automatic transmission assembly..?
Does it pull well during all other ranges..?
The automatic transmission assembly may be "tired" or worn out internaly.
Poor tourqe converter operation..?
Fluid level incorrect..?
Incorrect fluid type..?
Fluid filter..?
Engine throttle body assembly fault..?
For the transmission, it is not leaking. It was however a little low on fluid. I also managed to overhead it. I filled it with the correct fluid and it got better, stopped overheating, but still not right. Now that I'm home I'm going to drop the pan on the trans and transfer case. I'll dig in the FSM tomorrow., but any suggestions on things to check? Truck has 245k on it. I don't have the full history on the truck it is entirely possible that the transmission is worn. I just don't have a good baseline on what normal should be.
Last edited by gte718p; 09-21-2014 at 06:00 PM.
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#8
I wasn't really watching, but it was over 30. It was in low, I didn't feel a gear change, but I didn't feel any drag either.
#11
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It sounds like it didn't stay in first gear, but shifted up into the higher gears. Otherwise it's unlikely you could have hit 30mph. 30mph in first gear on an auto tranny in lo range would be over 7000 rpm. You'd have carried the engine home in a basket if you did that.
Are you sure you had it pulled into low gear, or was it still in drive?
I drive a manual for my offroading these days, specifically because I like the better downhill speed control. However, I have wheeled with automatics in the past, and generally found engine braking to be adequate when forced into a low gear, although not nearly as good as with a manual. Where the auto really fails you is if the engine dies. Without the front pump working, it's pretty much into free wheel mode. Couple that with the loss of your power brake assist and it gets exciting real fast on a steep downgrade shelf road with a 1000 ft dropoff off the side and a 3-point hairpin turn coming up.
Are you sure you had it pulled into low gear, or was it still in drive?
I drive a manual for my offroading these days, specifically because I like the better downhill speed control. However, I have wheeled with automatics in the past, and generally found engine braking to be adequate when forced into a low gear, although not nearly as good as with a manual. Where the auto really fails you is if the engine dies. Without the front pump working, it's pretty much into free wheel mode. Couple that with the loss of your power brake assist and it gets exciting real fast on a steep downgrade shelf road with a 1000 ft dropoff off the side and a 3-point hairpin turn coming up.
#12
It sounds like it didn't stay in first gear, but shifted up into the higher gears. Otherwise it's unlikely you could have hit 30mph. 30mph in first gear on an auto tranny in lo range would be over 7000 rpm. You'd have carried the engine home in a basket if you did that.
Are you sure you had it pulled into low gear, or was it still in drive?
I drive a manual for my offroading these days, specifically because I like the better downhill speed control. However, I have wheeled with automatics in the past, and generally found engine braking to be adequate when forced into a low gear, although not nearly as good as with a manual. Where the auto really fails you is if the engine dies. Without the front pump working, it's pretty much into free wheel mode. Couple that with the loss of your power brake assist and it gets exciting real fast on a steep downgrade shelf road with a 1000 ft dropoff off the side and a 3-point hairpin turn coming up.
Are you sure you had it pulled into low gear, or was it still in drive?
I drive a manual for my offroading these days, specifically because I like the better downhill speed control. However, I have wheeled with automatics in the past, and generally found engine braking to be adequate when forced into a low gear, although not nearly as good as with a manual. Where the auto really fails you is if the engine dies. Without the front pump working, it's pretty much into free wheel mode. Couple that with the loss of your power brake assist and it gets exciting real fast on a steep downgrade shelf road with a 1000 ft dropoff off the side and a 3-point hairpin turn coming up.
I prefer manuals. My crawler is a 5 speed with double a double reduction box. I rarely even use the brake on down hills. Unfortunately this truck came with an auto. I built it for the wife and she likes the auto so it is most likely staying.
#13
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Understood. Sounds like you're plenty experienced and know what you're doing on the trails - sorry if I seemed like I assumed otherwise.
I think I'd take it out on a quiet highway, accelerate to about 40 mph in 2wd, and progressively pull the shifter from "D" into "3", "2", and then "1", waiting for it to slow down appropriately for each shift. You should feel significant engine braking each time you downshift. If it refuses to downshift, then you have some troubleshooting to do. There are controls which prevent it from downshifting, even manually, if speed is too high - could be something wrong with that part of the system.
I think I'd take it out on a quiet highway, accelerate to about 40 mph in 2wd, and progressively pull the shifter from "D" into "3", "2", and then "1", waiting for it to slow down appropriately for each shift. You should feel significant engine braking each time you downshift. If it refuses to downshift, then you have some troubleshooting to do. There are controls which prevent it from downshifting, even manually, if speed is too high - could be something wrong with that part of the system.
#14
Understood. Sounds like you're plenty experienced and know what you're doing on the trails - sorry if I seemed like I assumed otherwise.
I think I'd take it out on a quiet highway, accelerate to about 40 mph in 2wd, and progressively pull the shifter from "D" into "3", "2", and then "1", waiting for it to slow down appropriately for each shift. You should feel significant engine braking each time you downshift. If it refuses to downshift, then you have some troubleshooting to do. There are controls which prevent it from downshifting, even manually, if speed is too high - could be something wrong with that part of the system.
I think I'd take it out on a quiet highway, accelerate to about 40 mph in 2wd, and progressively pull the shifter from "D" into "3", "2", and then "1", waiting for it to slow down appropriately for each shift. You should feel significant engine braking each time you downshift. If it refuses to downshift, then you have some troubleshooting to do. There are controls which prevent it from downshifting, even manually, if speed is too high - could be something wrong with that part of the system.
I also tried it in 4 low. There is no difference in 2 High and 4 low which seems to reinforce the idea it is not engaging gears. I'm also getting some god awful noises out of the tranny/transfer case. It is s clicking/creaking sound. It sounds like an auto locker that is clicking when not engaged.
I also checked the fluid. I'm overfilled a little. Color is good, it smells a little burnt, but not horrible. I'm still going to change it and drop the pans this week.
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