• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

727 Issue - 77 W150

69L48Z27

69L48Z27

Well-Known Member
Local time
9:13 PM
Joined
Nov 19, 2015
Messages
3,855
Reaction score
4,211
Location
York, Pa
First, this is not in a B Body. I have a 77 W150 with 318, and full time transfer case. All stock and I’m sure the trans has never been apart.

Fluid is full and looks good.

Symptoms:

- After driving for a while (10+ miles) and the truck is good and hot it will do this, never when cold or the first part of a longer drive. When I sit at a light in gear (more than 30 seconds) and I give it gas to go, it acts like it’s in neutral and then goes into gear. It may get up to 1500RPM. The harder on the gas, the harder it slams. Reminds me of doing a neutral drop. In gear idle is 700RPM.

- Only other issue is cold and reverse. After the truck sits for a week or so it takes a lot of RPM to engage reverse and get the truck to move. Seems like it’s slipping. Once it gets warm or even driven daily it doesn’t do it. I’ve started the truck in neutral and it makes no difference.

Other than that the trans doesn’t slip and it shifts really good, kick down is good too.

So, what am I looking at? Bands, servo, converter, full rebuild? Hoping this is a common symptom of an adjustment needed.

TIA.
 
the bands are slipping. get a service manual, adjust the bands. if that doesn't do it , a rebuild is in order.
 
My old 76 W150 used to do the "neutral drop" thing too. I always thought it was slop in the full time transfer case.
 
if you drop the pan check the low / reverse servo and band auj as said hear . you might be able to remove the servo and check the sealing rings to see why it is losing fluid that is applying and holding the band
 
How about this ‘converter drain back’ thing? I did some more research last night and saw that this came up a lot.

Front pump bushing being bad was the problem.

I’ll be R&R the engine to reseal it this winter. I’ll probably wait until then to service it.
 
69L48Z27 said:
How about this ‘converter drain back’ thing? I did some more research last night and saw that this came up a lot.

Front pump bushing being bad was the problem.

I’ll be R&R the engine to reseal it this winter. I’ll probably wait until then to service it.
Click to expand...


when the engine is running that cant happen as the pump is turning and makes the pressure.
 
493 Mike said:
Sounds like old, hard seals to me. Time for a rebuild.
Mike
Click to expand...

I agree, when it warms up, the fluid thins out and leaks past the seals but a little "miracle in a bottle" might squeeze a few more miles out of it.
 
WP29440SE said:
the bands are slipping. get a service manual, adjust the bands. if that doesn't do it , a rebuild is in order.
Click to expand...
no, no, and no. Bands have nothing to do with this issue. My bet is it's worn out. The torque-Flite uses the forward clutch for 3rd and reverse. It uses the low /reverse band for manual low and reverse. It doesn't need any rear band actuation foe D low. If it bangs in low and slips in reverse that would be 2 separate issues. Its possible the fluid flow is restricted or the pressure is low. The filter may be be partially blocked. But if it is, the debris came from worn parts.
Doug
 
Last edited:
vance.dykes said:
when the engine is running that cant happen as the pump is turning and makes the pressure.
Click to expand...
I guess I was referring to my number 2 issue with cold start and reverse. System needs to ‘pump’ back up.
 
What the heck does one use for transmission fluid these days in the old 727's since you can't get regular Dexron?
 
dvw said:
no, no, and no. Bands have nothing to do with this issue. My bet is it's worn out. The torque-Flite uses the forward clutch for 3rd and reverse. It uses the low /reverse band for manual low and reverse. It doesn't need any rear band actuation foe D low. If it bangs in low and slips in reverse that would be 2 separate issues. Its possible the fluid flow is restricted or the pressure is low. The filter may be be partially blocked. But if it is, the debris came from worn parts.
Doug
Click to expand...
if you say so. thats why I just buy replacements instead of ******* with them. if they start slipping , I toss em in a ditch and get another one.
 
I could count the number of low/reverse bands needing replacement on one hand. Been building Torque-Flites for almost 40 years. The intermediate bands do wear but they apply 2nd gear only. You are correct if the bands have been slipping there is an issue. But seldom do both of them slip. My 9.0 race car has a 65 L/R band that came with a core. Whens the last time you priced a good solid red lined band?
Doug
 
You must log in or register to reply here.

Similar threads

GassMann
727 transmission clunks into drive or reverse
Replies
6
Views
574
GassMann
GassMann
Christian-440
Torque converter issues?
Replies
6
Views
480
Christian-440
Christian-440
3sloppydogs
727 question
Replies
4
Views
661
Dave6T4
Dave6T4
icetech
Bad fresh 727 noises
2 3 4
Replies
63
Views
1K
icetech
icetech
HAHNAGON
REBUILT 727 HARSH SHIFT INTO REVERSE ONLY
2
Replies
32
Views
1K
oldkimmer
O
Auto Transport Service
Back
Top