01' Suburban slow to shift into reverse

[311Hemi]

Any thoughts on what would cause my Suburban to be slow in shifting into reverse this morning (~10 sec). It seemed to go into drive just fine. It's probably one the coldest mornings I have driven it so far. After driving a mile and then using reverse again it seemed to work just fine with no delay.

[SkunkedAgain]

First step would always be to check the tranny fluid to make sure that it's at the right level. In general though, transmissions can shift slower when cold but 10 seconds is a long time. Before you even think about anything else more difficult or expensive, check the fluid level.

[311Hemi]

Tranny fluid level was good when I checked it 3 weeks ago (when I bought it), but I will double check again! I was told the tranny fluid was changed in the past 6 months.

[Macgyver55]

Delayed or no reverse is sometimes/often a sign of a cracked "sunshell". Unfortunately it isn't something that can be repaired easily and is somewhat common in the earlier 4L60E transmissions. Its not always the case, and hopefully its something less, but if you bought the vehicle from a dealer I would inquire about it early on in case they will help you with it if it turns out to be the problem.

Some will remain cracked and go a long time, others will continue to crack until they break and cause further internal damage.

[311Hemi]

Checked the fluid tonight and it was right at the lowest yet still acceptable mark....right on the line. After driving a mile or two the it goes in and out of gear in both directions just fine. I will try adding a little fluid to see if that helps.

Truck was purchased from a private party so I am stuck with whatever is going on.

Does the tranny need to come out to check the sunshell if it comes to that? I think I also read somewhere that it could be a certain valve if line pressure is good.

Quote:

Secondly, put a line pressure gauge ($55 shipped on hsolist, or visit a local trans shop) on the pressure test port and go for a drive to verify proper line pressure. Base pressure at idle in P,N,OD should be around 70psi and around 140psi in R. Max line pressure should be at least 190psi at WOT in 1st or 2nd, 225psi is optimum. If base pressure is low, trans or pump is worn out. If max pressure is low, check EPC solenoid. If reverse is slow to engage, and line pressure does not come up to at least 130psi in reverse, replace the boost valve with a Transgo 0.500" boost valve (easy fix in pan).

[Macgyver55]

First off I'm sorry if I alarmed you with the possibility of a cracked sunshell. That's the last thing a guy wants to hear when he just bought a "new to him" vehicle. I only mentioned it because it was somewhat common for that vintage transmission. The other things mentioned are also good possibilities and should be looked into first as the sunshell is internal and would require the removal of the transmission. Myself? I would drop the pan as I would with any used vehicle I buy, inspect for debris in the pan, and replace with the recommended fluid and a good filter. That will give you a good indication and a known starting point for future maintenance.

Checking line pressures if you have the necessary gauges is also a great way to determine if there is an issue with low pump pressure or a valve body problem.