- This topic has 5 replies, 3 voices, and was last updated 10 years, 2 months ago by
.
-
Topic
-
The problem vehicle is a 94 Ranger 4.0 4WD Automatic. It has about 114K on it. I owned this truck for about 7 years, and never experienced this issue. My uncle owns the truck now as his backup vehicle. He’s old and retired, so he doesn’t travel far. Or fast for that matter. Yesterday my brother had to borrow the Ranger, as his Blazer is in the shop. He has a about a half hour – 45 minute highway drive to work. It’s mostly uphill since the highway travels up a mountain. He reported to me that the truck started shaking while on the highway at around 65 mph.
I looked underneath the front end tonight and everything seems in place. I took it for a drive and I could not replicate the shaking. Even on the highway at 65-75 mph it didn’t shake, so I ruled out unbalanced tires. Then I took his route up the mountain. The truck seems to stutter while it’s in its highest gear, around 1500-2000 RPM, about 55+ mph, but ONLY when going up a fairly steep consistent grade. If I give it more gas to make it downshift and bump it up to 3000 or more RPMs, the shaking goes away. The shaking feels like a cylinder is misfiring. I have no check engine light when this happens.
So this problem kept getting worse. It was beginning to act up in 3rd gear as well, and the bucking got really really bad in 4th. I changed the coil, plug wires, and spark plugs, and fuel filter. One of the plugs (number 6 I think – the one nearest the heater core) porcelain was broken near the bottom of the electrode. After changing these the truck does run better, but still feels like it is misfiring in 4th gear. It’s not as bad now, but still very noticable. I still don’t have any check engine lights. Any more ideas? Injectors? Transmission issues? I’m stumped. Thanks for any help.
-
Replies
-
One of the first automatic transmissions I ever rebuilt was an A4LD which is what I believe you have. They had a very high failure rate and based on your description I believe you may be experiencing a transmission issue. That being said if you’re looking to save money and you do determine that it is indeed a transmission problem, I would suggest replacing it with a rebuild unit for best results. More info on transmission issues here.
http://www.ericthecarguy.com/faq/solving-transmission-problems
Good luck and keep us posted.
Thanks for the quick reply Eric. When I first encountered this problem I feared it was a transmission issue. Then someone recommended trying the tune up that I mentioned above. As I said the condition DID improve, so I was hoping maybe I was on the right track, but still missing something. I’ll continue to dig into it as time allows and update this post with any new info. Thanks again!
Had someone call into a local ‘car talk’ show with an issue like this. Turned out to be the TCC (Torque Converter Clutch) pressure was weak–so when under a bit of load the TCC was applying–but not with enough pressure to hold the clutch tight. So it would slip and cause a chattering effect much like a “Stutter” would seem like.
Eric knows I have the A4LD in my Bronco II. And yes, they are a handful to maintain. I’m on the fence with this.
Let’s try this for size. Take the truck out for for a test drive. Manually shift the truck up to “3”. Or “D” depending on what your shift selector says. (Could have a “D” with a circle around it. Do NOT select that. Just the normal “D” or “3”.) Trick is to have the truck in 3’rd gear and not overdrive. Take it out for the drive up a good size hill—Further load the engine a bit by applying the brakes a bit. You want to make the engine get under a load–much like if the truck was in 4th gear (overdrive). If doing this test–the engine doesn’t start to stumble/shake/stutter/etc.. And it remains rock solid? Good chance the overdrive in the transmission has a slipping clutch pack. Which is sadly common for these.
Please do not do that test for an extended amount of time. It will heat the transmission and brakes up quite a bit. Suggest maybe 10 seconds at a time with a cooling off period so as not to ‘bake’ anything.
When was the last time the transmission had a fluid and filter change? I’m not suggesting to do one at this time yet–With older transmissions changing fluid and filter ‘can’ actually do more harm then good. As the old fluid causes varnishes to build up–and that’s what is holding the transmission together. New fluid has new detergents that ‘can’ remove that build up–and then you’ll have line pressure issues. It’s a 50/50 that it helps—or does more harm then good. I’ve always suggested to people to change the fluid every few years or 40-50k intervals.
S-
I’m aware that changing the transmission fluid after a long time can be harmful. Sadly, my uncle was not. He had it done last year. When I had the truck, I had no idea how long it had been so I left it alone. I have tried putting the transmission in “D” and driving like that. It doesn’t seem to stutter at all, but I have only driven it up moderate hills in D. Though before doing the tune up, it DID start to stutter in 3rd gear. Afterward, I couldn’t feel it. I’ll try your test and get back to you.
- You must be logged in to reply to this topic.