Brake Issue - Diesel Forum

bcgeorge · 05-09-2007, 04:20 AM

I have 2 questions,

1) Most of the time when brakeing I get a severe jerking sensation like I have a warped drum or rotar, and other times it feels nearly normal. brakes work well, no ABS lights, no other chalanges, just have never been able to put my finger on the cause. Any gusses as to what is going on?

2) Lately on ocassion at 65-70 MPH the tach will jump by a couple hundred RPM like the tranny is going to upshift but there is no need or apparent demand, (running straight and level), and a couple of times lately the tranny has "engaged" more than normal at a stop light or in reverse. the RPM's lug down to nearly 500 (my normal idle speed is 650 or so) I no verry little about auto trannys, any input will be apreciated. Thanks for the help.
Brent

cdnsarguy · 05-09-2007, 06:28 AM

Front rotors do 60% of the braking effect, could be a rear drum out of round coming into play or a front caliper hanging up. How are the front bearings, jack up the front and do a wheel wiggle test.

What is the front end/steering gear like... could it be a brake induced death wobble........Does it happen at all speeds or just high or low.

arthurgoboom · 05-09-2007, 11:58 AM

On your second issue...it sounds like your torque converter is locking and unlocking at times that it's not supposed to, i.e. unlocking at 65-70mph, locking while sitting at a stoplight or in reverse. As for a cause...I dunno, someone else will have to give ideas.

Mr_Roboto · 05-09-2007, 12:11 PM

TCC locking in reverse is caused by pressure leaking from the front pump into the TCC apply circuit.

Truth be told I don't know if the leak is through an O-ring or paper gasket, I would try adding some Trans-X in case the offending part is rubber.

Unfortunately the TCC locking up will eventually be fatal to the transmission, or at the least fatal to the TCC.

bcgeorge · 05-09-2007, 12:26 PM

Did a google search on death wobble, dont think its that as I replaced tierod ends just after I first noticed the jerking W/O change. I also looked at the kingpins at the same time, did'nt find anything to be concerned about, no tire wobble, front tire wear seems normal and good. The jerking can happen at any speed and only occures when braking. I've never had a problem with it after hitting a bump or while turning a corner.

Assuming the trany issue is the TCC locking and unlocking how much time do I have before it gives out all together?
Thanks for the input.
Brent

Mr_Roboto · 05-09-2007, 02:56 PM

[ QUOTE ]

Assuming the trany issue is the TCC locking and unlocking how much time do I have before it gives out all together?
Thanks for the input.
Brent

[/ QUOTE ]

It depends if the clutch material in the fluid kills the trans or not. I had a gasser van that did the same thing, I got in the habit of fueling while going onto reverse to keep the motor from stalling and eventually the TCC clutch just wore out and it quit. The van was a POS so I didn't worry about it. I only drove it for a couple months with the clutch burned out before I got a better van so I have no idea how long the trans would have lasted.

Once the TCC wears out your trans will run A LOT hotter due to the converter slippage.

bcgeorge · 05-15-2007, 10:23 PM

I am considering replacing the E4OD with a manual overdrive trany but not sure which one to be looking for? would like a 5 speed overdrive if its an option. How much work am I looking at to do the swap. Will I have to replace the transfewr case as well? Thanks for the help
Brent

stevebondy2000 · 05-16-2007, 03:04 PM

I just had the same problems with my brakes, it turned out the back drums were worped. When you are driving step on your e-brake and see if you feel the jerk, if so it is the back if not it is the front. Good luck.

dlblack · 05-19-2007, 09:08 PM

On the first question...
When you say jerking sensation does that mean side to side.
When i first got my van it did that just going down the road and you never new when it was going to pull side to side.
I had the original calipers on mine with the plastic pistons in the calipers. I got rid of them when i found out that and put steel pistons calipers on and it has never jerked or pulled side to side ever again.
If you got the plastic piston calipers get rid of them.
Dwight